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3rd   International Symposium on Turkey Diseases

Berlin, 14th  - 17th  June 2000

This is the third meeting on turkey diseases organised at the same venue by Prof. Hafez. These are my notes of the presentations, grouped according to some of the subject areas rather than order of presentation. They are offered not as a transcript but as a "best effort" at a personal interpretation of the papers. This document is a very poor substitute for being at the meeting (maybe next time I can arrange a video-clip of the after-dinner entertainment!).

If you are an author and would like to correct any errors I may have made in this text please forward the specific correction by e-mail: (mailto:corrections@poultry-health.com)

The full proceedings will be available in a few months - see contact details at the bottom of this document.

Special congratulations to Dr Jane Cook to whom this meeting was dedicated on the occasion of her retirement. Dr Dick Jones did an excellent job at the beginning of the meeting outlining her many contributions to poultry disease research, and we all enjoyed the cocktail session in her honour.

Many thanks to Prof Hafez for organising this meeting and allowing us to make this available on the Poultry Health Services site. Thanks also to Bayer Animal Health for organising my participation in the meeting.

Paul McMullin

Thirsk, 6th July 2000


Food Safety

Ref Number : 310
19. Kasbohrer, A. New zoonoses directive: Strategies and their consequences for turkey production. TurkBerlin00 2000.
Keywords : zoonoses; turkey; production; Human; Salmonella; control; Antibiotics; resistance; disease; Animal; risk; Chickens; broiler; turkeys; chicken; Birds;
Notes : We are currently working under council directive 92/117/EEC. This covers monitoring and reporting of zoonoses which pose a threat to human health in particular dealing with Salmonella control programmes. Over the past few years the Commission has been preparing a new draft directive and regulation. The directive will deal with monitoring and the regulation will deal with the control. The draft documents are currently being discussed in various working groups. The objectives establish appropriate and sufficient monitoring of zoonoses, collecting relevant information in member states, and analysing these. The directive will have general rules for monitoring - to include pathogens and monitoring of antibiotic resistance. It is intended that the monitoring programme should be coordinated and that epidemiological investigation of foodborne outbreaks of disease be conducted. Regulation - to ensure that appropirate and effective measures are taken to control the zoonoses. this will include adoption of targets to reduce the prevalence of specified zoonoses adoption of specific control programmes adoption of specific rules applied to reduction of zoonoses. adoption of rules concerning intra-community trade and imports form third countries of specified animals Community targets - to reduce the risk to public health posed by zoonoses. The annexe will specify agents, animal populations, dates for achievement, requirements with respect to trade. On Salmonella only serotypes of interest to public health will be included - e.g. S.e. in laying hens, more serotypes in chickens and broilers. Currently turkeys are not mentioned with respect to breeding flocks. Targets to be established by end of 2002 for chicken breeding flocks, 2005 for turkeys - trade effects to start 1 year later. Control programmes provide for the detection of zoonoses and agents thereof Define responsibilities of food business operators Specify the control measures to be taken Identify the means to re-evaluate the programme. The programme must cover feedstuff production, primary production of animals, processing and preparation of foodstuffs of animal origin. General requirements - Aim - occurrence of the zoonoses geographical area list of approved laboratories methods used in the examination of the zoonotic agents, including sampling schemes type of measures if zoonotic agents are detected Current minimum requirements for broilers are to be day old and slaughter, turkeys at slaughter. Originally vaccination of breeding birds was to be banned, currently flexibility on this is to be maintained at the discretion of the commission. Laboratories must be specifically approved and participate in QA schemes operated by national reference laboratories

Ref Number : 311
20. Borck, B., Pedersen, K. and Madsen, M. Campylobacter in Danish turkeys. TurkBerlin00 2000.
Keywords : Campylobacter; turkeys; Human; Denmark; Salmonella; broiler; infections; control; management; Germany; analysis; Meat; risk;
Notes : The author is working on a 3 year study on campylobacter in Danish turkeys. Camplyobacter is a leading cause of diarrhoea in humans - in Denmark campylobacter hs overtaken Salmonella as a cause. There is a constant increase in campylobacter cases since 1980, in Iceland and New Zealand this rise has been particularly dramatic. The Iceland effect has been attributed to cessation of mandatory freezing of broiler carcases. There is a marked annual cycle of Campylobacter infection in both humans and broilers - the cycles match very closely. This project aims to examine the occurrence from "stable to table" It aims to look at risk factors of infection and colonisation and identify critical control points including slaughter and processing. Eventually the project aims to evaluate methods of campylobacter detection and assess their usefulness in process management. Currently about 1 million turkeys are produced in Denmark, imported as poults from Germany and grown on 24 farms and slaughtered in a single plant - standard houses except for a group of farms in Jutland. Material & methods - 10 swabs taken from each batch, placed in BHI broth. In the lab they are pooled in 3 ml of sterile water then streaked onto CCDA plates, incubated in microaerophilic athmosphere for 3 days. Isolates are colony selected and sub-cultured until monocultures are obtained. This is the same method applied for broilers in Denmark. Results to date were presented and show 60-90% positives except for march (20%) and April (5%) - May is up again. The overall average is 50% of batches, 56% of flocks As expected C.jejuni was dominant (90%) among the isolates - 3 C.lari from a single farm in Furhter work will involve analysis of slaughter and meat processing, quantitative studies of occurrence in turkeys

 

Ref Number : 286
2. Horrox, N. Food Microbiology - Issues for Reflection. TurkBerlin00 2000.
Keywords : control; poultry; veterinarian; food microbiology; Salmonella; TVC; quality control; accreditation; legislation; risk;
Notes : Quality control of food testing has progressed significantly in recent years. The author speaks from the point of view of a poultry veterinarian with a UKAS accredited food testing laboratory. Major supermarkets now require independent laboratories to be accreditied by UKAS - a laboratory can be accredited even if only 1 test is accredited - both laboratory and test need to be accredited. Accreditation helps tell us what is happening in our laboratory and relates to how much faith we have in the results. Interpretation of results: Negative - should be replaced by "Not detected" We require a representative number of samples collected and processed appropriatedly. If we are testing a 25 g sample and can detect 1 organism - this equates to 40.000 in a tonne or a million per wagon load! Even non-detection could allow up to 1 million organisms per load. Internal/external challenge testing. The following results refer to the Qm food testing now operating in 30 countries. Assessment of returned scores with respect to expected results uses a Z statistic (perfect = 0, 2 or higher unacceptable). Returned results tend to be normally distributed. Laboratories spend 10-20000 dm/year in order to stay in this scheme. UKAS does not remove labs on the basis of a single bad result - requires continuous improvement of outliers. Different laboratories perform differently on different test. Good laboratories aim for Z stats of 1 or less. In a recent QA test for Salmonella at 10 organisms/gram, 10% of laboratories failed to detect. Recent British legislation tends to take food poisoning out of the category of "absolute offence" - the "due diligence defense". This may be relevant to those of us running laboratories. The features of this defense are: 1. were you aware of the risks? 2. have you taken measures to remove or minimise risks? 3. are you regularly checking the situation 4. Are we analysing results of checks and acting on unacceptable results 5. Do we seek appropriate advice and guidance.

Ref Number : 313
14. Schroeter, A. and Helmuth, R. Resistance of salmonella isolations from turkey in Germany. TurkBerlin00 2000.
Keywords : resistance; Salmonella; turkey; Germany; feed; environment; Animal; turkeys; typhimurium; Incidence; Meat; DT104;
Notes : The authors' organisation examines annually 4-7000 salmonella samples- the range of species involved is fairly similar from year to year. Samples come from feed, food and environment as well as animals. Certain serovars are more common from turkeys typhimurium, saintpaul, blockley, hadar, newport, indiana. There is a moderate incidence group which includes S.e. There are a large number of other isolates which occasionally occur. Heidelberg seems to be a growing problem. For testing a german standard method 58940 disk diffusion method is used. Resistance tends to be high in S.typhimurium, and other high prevalence Salmonellae. Multi-resistance was seen in many isolated, though the percentage of isolations is dropping. The serotypes on meat which are multi-resistant to 6 or more are S.newport and typhiumurium in both years - the same is true for S.anatum, in addition to newport and typhyimurium. Data were also presented on MIC results on a sub-set of strains of S.heidelberg and S.anatum. 21 of 27 S.typhimurium isolates were determined to be DT104.

Ref Number : 312
15. Hafez, H.M. and Mazaheri, M Bacteriological investigation on salmonella in meat turkey flocks. TurkBerlin00 2000.
Keywords : Salmonella; Meat; turkey; consumer; legislation; control; production; E.coli; Campylobacter; disinfection; transport; Female; Male;
Notes : Safe food is a fundamental requirement for all consumers. The expectation of the consumer may involve lack of immediate health hazard, but long term health, correct composition, health benefits and quality become additive demands. The current legislation is not enough and industry must accept a greater share of responsibility. The control must go all the way from initial production through to the consumer. Processing plants are not able to effectively decontaminate products. In this study 7 flocks which were negative on farm, frequently had salmonellae after processing. A similar study demonstrated VTEC E.coli after processing. Campylobacter jejuni can be readily identified on farm but gross contamination in processing also occurs. Cleaning and disinfection in processing plants was found to be highly effective. Effort must be made to reduce contamination prior to dispatch to processing. This needs to include knowledge of which flocks are positive, processing logistics and transport. There is currently no requirement for testing meat turkey flocks for salmonella prior to slaughter. Currently there is debate between producers and consumers. C&D must follow the slaughter of known infected flocks. To date 9 cloacal samples have been taken from each of 540 turkey flocks 3 weeks before processing. - only 9% were positive for Salmonella in 1999, 19% in 2000 to date. The most frequently isolated groups were in groups B,C,D,E, Newport, enteritidis, anatum, agona, heidelberg, bredeny - the rise in 2000 is related to heidelberg. There were 23.4% of farms positive and only 6.2% were repeated positives - most were related to successive depletions of females and males, the remainder were mainly different serotypes. Results - Salmonella of serovars were found - positive flocks were slaughtered at the end of the day and meat use from them was adapted accordingly, hygieneic measures were discussed with the company. Legislation alone will not deal with this - the industry must take a greater responsbility. Measures to reduce contamination pre and post harvest are necessary

 

Ref Number : 314
17. Stephan, B., Reynolds, D.J., Gibson, S.A., Johnson, A.C. and Froyman, R. Direct challenge and floor pen trials assessing the efficacy of Competitive Exclusion (Aviguard) against different Salmonella serovars in turkeys. TurkBerlin00 2000.
Keywords : Salmonella; turkeys; infections; turkey; Birds; typhimurium; DT104; Chickens;
Notes : Since Nurmi and Rantala proposed the principle of competitive exclusion in 1973 it has been widely accepted. Efficacy of the competitive exclusion product Avigaurd for Salmonella in turkeys has been reported in the literature. One trial involved birds challenged with 10^4 S.kedugou and evaluation 7 days later. Results must be assessed using the calculation of the infection factor and from these values for each group a log reduction ratio is calculated. This trial involved 2 groups treated with the product by spray, 2 by oral gavage with product and with adult turkey caecal contents - reductions of 4-7 were achieved, highest in the turkey caecal contents group. In a second floor pen trial seeder birds challenged with S.livingstone and S. typhimurium were used. Reductions achieved were 86% fopr DT104 and about 45% for S.livingstone. Batch comparison data were examined with 2 levels of Salmonella keduguou challenge (10^3 and 10^4) achieved about 5 log reductirons. A dose titration study compared 1/10th and full dose with 10 doses- 1/10th dose achieved little protection in chickens and 2 log reduction in turkeys, compared to 6 in both species at full dose. Overdosing did not boost efficacy. A previous paper (av Dis, 1982 585-595) examined the relative protection of CE in chickens and turkeys. The reviewed literature suggests that CE products based on turkey flora have a wider protective effect than those derived from chickens - Aviguard appears to have higher log reductions in chickens than in turkeys but also it produces better protection in turkey than other products which have been tested.

 

Turkey Enteritis

Ref Number : 306
22. Saif, Y.M. Enteric viral infections of turkey poults. TurkBerlin00 2000.
Keywords : infections; turkey; adenovirus; enteritis; Intestines; histopathology; intestine; bacteria; culture; electron microscopy; reovirus; epidemiology; resistance; virus; anatomy; turkeys; disease; PEMS; growth;
Notes : Experimentally rotavirus, astrovirus, coronavirus, enterovirus, adenovirus and possibly reoviruses can cause enteritis experimentally. Diagnosis: Clinical signs and lesions are not diagnostic but typically poults are affected between 1-3 weeks of age - noisy, diarrhoea, excessive drinking, low mortality, high morbidity. Pathology: Caecae and intestines distended. Gut walls flaccid, transparent and full of liquid contents and gas. Caecae commonly have yellow frothy contents. Histopathology - hypercellularity of small intestine lamina propria, scalloping of surface and vacuolation of epithelium, separation and desquamation of enterocytes, bacteria adherent to villi, villus atrophy. On SEM villi are roughened due to desquamation. Malabsorption/maldigestion is a common sequel and secondary nutritional problems - abnormal feathering, skeletal deformities etc. A major problem is that the viruses involved are difficult or impossible to culture. Direct and immune electron microscopy are useful - use acute and convalescent serum. Genome electopherotyping is useful for rotavirus and reovirus. Immunoflourescence and immunoperoxidase can be useful. Epidemiology - enteritis is common in commercial flocks. Route of transmission is faecal-oral. Combined infections are common. Viruses vary in resistance to environmental conditions. Survey results vary but typically Astro and Rotaviruses are most common in both sick and normal but % prevalence much higher in affected flock. Sampling 4 flocks in detail showed astrovirus in all flocks, from as early as 4 days to 5 weeks. Rotaviruses may be found in the same time frame. Adenoviruses are generally post 5 weeks and are HE virus. Anatomy - villus epithelium - mature nonproliferative cells differentiated for digestion/digestion - crypt cells are proliferating non differentiated and are more involved in secretion. When there is extreme villus atrophy there is secretion with reduced absorption - this is an important mechanism of diarrhoea but not the only one. Different viruses have predeliction for different parts of the gut - mixed infections tend to be additive in effects Rotaviruses - four serogroups - group D is most common. These are the most common cause of early enteritis. Astroviruses - a recognised pathogen in turkeys and some mammalian species Coronaviruses - the cause of what used to be called bluecomb disease. A highly labile virus which is probably the most devastating enteric viral infection in turkeys. Used to be considered species specific, high rates of mutation. Reoviruses - a controversial subject as to whether they do cause enteritis - difficult to reproduce disease. PEMS: An acute transmissible disease of turkey poults 1-4 weeks of age characterised by diarrhoea, anorexia, growth depression, immune dysfunction and high mortality. It has driven many people out of business. It is a mixed viral enteritis. Investigations have shown rotavirus in 72% of flocks, astrovirus (SRV) in 44% and turkey coronavirus in 22% - mixed infections were common. The disease can be readily reproduced by filtered bacteria free gut contents. It causes a rapid onset depression and subsequent scour and weight depression. The turkey coronavirus and astrovirus were additive in weight depression effect. The astrovirus was detected in many tissues including thymus, bursa and spleen. It reduced the lymphoproliferative response to ConA and reduces circulating CD8+ cells. Recent studies suggest that the Small round virus is a newly emerged astrovirus. Bovine coronaviruses are similar to turkey coronavirus - at least one isolate from calves has been shown to cause disease in turkeys but not in chicks.

Ref Number : 307
21. Dobos-Kovacs, M., Dren, C.N., Tovari, J. and Vetesi, F Diagnostic problems of enteritis and growth retardation in turkey poults in Hungary. TurkBerlin00 2000.
Keywords : growth; turkey; electron microscopy; enteritis; virus; disease;
Notes : These are preliminary results on a new problem in Hungary. Diagnosis - definition of the gross and microscopic lesions is still the main criterion. Viruses may be isolated and detected in other ways (electron microscopy, immune electron microscopy). Work in this area is complex and even if the viruses are identified there is the issue of the cause and effect relationship. In principle immunocytochemistry is a possibility. It is surprising that there is little work on the molecular biological techniques which might overcome some of the current problems. Materials and methods. Standard light and thin section electron microscopy - immune electron microscopy - sera provided by Dr Saif. Method followed as per AAAP manual. Samples are prepared by homogenisation and sonication of complete intestinal contents - filtered and pelleted. Results - Indirect immunoflourescence - problem with non-specific reactions from antibody producing cells. Pathology - marked enteritis and frothy caecae. EM: Viral particles seen mainly in cells in the lamina propria, usually in dense intracytoplasmic inclusions - containing 29-33 nm particles. Immune IE shows partial clumping with astrovirus antiserum. It appears that this problem is caused by this virus - work is planned on the attempted reproduction of the disease, hopefully the results will be available for the next meeting.

Ref Number : 281
3. Jodas, S. and Hafez, H.M. Litter management and related diseases in turkeys. TurkBerlin00 2000.
Keywords : management; disease; turkeys; poultry; production; control; nutrition; environment; risk; dust; feed; chemical; bacteria; Air; Birds; Incidence; Haemorrhagic enteritis; enteritis; virus; PEMS; Coccidiosis; Temperature; Antibiotics; infections; resistance;
Notes : For effective poultry production litter management is as important as many other aspects of mangement and health control. Litter dilutes faecal material, insulates from cold floors. Bedding material must be stored in a dry area. Minimum depth should be 5 cm, caked litter should be removed and new litter added as required. Tilling litter may be helpful to achieve moisture of 25-35%. Friable litter helps breakdown. Wet and caked litter can arise over the course of a few days when diarrhoea is severe. Various factors are involved - nutrition, disease, physical environment. Increase ammonia can cause respiratory disease, keratoconjnunctivits, and reduced immune response. High moisture increases risk of a range of diseases. Litter moisture below 20% increases risk of respiratory disease from dust. Fat and nitrogen in faeces can cause contact dermatitis. Feed - any mecanical, chemical, formulation problem can be involved - ingredient quality, and formulation are critical. Deviations in feed coomposition can result in poor feathering as well. Faecal consistency is quite variable - varying wateryness, foamyness and colour. Caecal faeces are mainly present in the morning and 10-12 hours later. Factors increasing water consumption - minerals (potassium, chloride, soidum), raffinose, biogenic amines may be relevant. Water quality is vital - pH 6.8-7.5, free from bacteria, nitrate <50 ppm, nitrite, <0.1ppm, lack of chemical contamination. Drinkers must be appropriate in numbers, working correctly etc. Drinker fialures can directly cause wet litter, reduced weight gain etc. They should be washed daily. Poor water hygiene affects efficacy of vaccination by this route. Target environment RH 60-70%, NH3 <30 ppm, air movement 0.3 m/sec, at bird level,0.5 m at house level. Anderson et al compared ammonia and dust levels with respect to airsacculitis - both factors increased incidence and severity of airsacculitis, but especially dust - there were no interactions confirmed. Exposure to ammonia at 40ppm dramatically increases damage to the tracheal epithelium. House design - must proctect against elements, satisfy bird requirements, provide reasonable comfort. Must also facilitate management, and maintenance and facilitate hygiene. Interactions - many infectious and non-infectious problems can lead to wet litter. Haemorrhagic enteritis virus leads to bloody droppings and severe depression. "PEMS" causes marked diarrhoeas as does coccidiosis. Enteric disease cause significant problems General measures - raise temperature, decrease litter moisture, antibiotics to combat secondary infections, electrolyes, and improved hygiene. Hygiene measures have general effects. Other measures - vaccination for HE, competitive exclusion, coccidiostats, anti-histamonas etc. CE in conjunction with good hygiene has been shown to markedly improve resistance to a range of pathogens. All management practices affect each other and can both promote or inhibit poultry health.

Pneumovirus - Turkey Rhinotracheitis

Ref Number : 303
23. Van de Zande, S., Nauwynck, H. and Pensaert, M. Protection of avian pneumovirus (APV) vaccinated turkeys against an APV-E-coli challenge. TurkBerlin00 2000.
Keywords : pneumovirus; turkeys; vaccine; E.coli; Scoring; bacteria; serology; virus; control; Birds;
Notes : Previous work has suggested good cross-protection between types A and B at 3 weeks post vaccination, and only partial virological protection at 11 weeks post challenge. This study investigates whether a single vaccine could protect against a mixed APV-E-coli challenge. Vaccination was by I/Nasal at 10^2.3 ciliostatic doses with Aviffa and Poulvac. Virulent strains of pneumovirus and E.coli were from clinical cases. Both dual, APV and E-coli only groups were derived from each treatment group. The scoring system ranged from 0 to 7. Poults were antibody negative and vaccinated at 3 weeks. Bacteria were isolated and titrated. Serology was performed throughout using a SN test. The challenge strain was A type. More virus was present in the B-A group than in the A-A group at both 3 and 5 days post challenge (controls were much higher). E.coli was generally not reisolated in the AA group but in the BA had a sudden peak at 5 days - unvaccinated challenged birds had massive E.coli invasion. Serology shows peak antibodies at 5-7 weeks and a dramatic anamnestic response post-challenge. Conclusions - Clincal signs were much worse in non vaccinated birds, and there were 10^3 more virus and 10^7 E.coli. Cross protection showed that protection was somewhat better in the A group for A challenge.

 

Ref Number : 300
26. Bayon-Auboyer, M-H, Arnauld, C., Toquin, D. and Eterradossi, N Nucleotide sequence of the F, L and G protein genes of two non-a/non-B avian pneumoviruses (APV) reveal a novel subgroup of APV. TurkBerlin00 2000.
Keywords : pneumovirus; elisa; sequencing; genes; sub-types;
Notes : The avian pneumovirus the genome is smaller than mammalian pneumovirus genome and some of the genes are in different orders. In both groups the G gene is the main target for sero-neutralizing antibody. Initially groups A and B were identified by antigenic differences, Elisa, Mabs. When sequencing was carried out it was found that there was only 38% amino acid identity. To date a sequence of the American C type is not available. This work was done with non-A/non-B isolates made in 1985. Cross-elisa testing suggests variation in antigenicity which make them separate from both A, B and Colorado. One of the strains F/85/1/APV was replicated in vero cells and was then amplified and sequenced. It was found to have low conservation of the SH-G and G-L intergenic regions - overall nucleotide identitity was only about 56% for both A and B strains though the two strains were nearly identical, only 31% identity for amino acids. This paper should serve as an alert that avian pneumoviruses are much more diverse than previously thought and highlights the need for continuing vigilance of these infections.

Ref Number : 302
27. Worthington, K.J., Sargent, B., Davelaar, F.G. and Jones, R.C. Immunity to TRT in turkeys following in-ovo vaccination. TurkBerlin00 2000.
Keywords : immunity; TRT; turkeys; Animal; Birds; stress; disease; vaccine; elisa; incubation;
Notes : This forms part of a project supported by Fort Dodge Animal Health. Why in-ovo? This provides an accurate individual dose as compared to spray. Possible reduced bird stress, ease of automation and possible earlier immunity. In-ovo administration has been used in a number of diseases. There appear to be no papers on the use of this technique in turkeys. It was planned to evaluate safety and efficacy with Poulvac TRT a live attenuated vaccine of normal spray dose 10^4.2 TCID. To evaluate safety eggs were obtained from antibody negative parents and an overdose (10^1.3) of vaccine was used. Hatchability and poults post hatch were evaluated. A total of 72 eggs were used. Hatchability was satisfactory. Nasal scores were recorded daily. Only 36% of the vaccinated birds showed signs - maximum effect at 6 days post injection. Signs were mild as compared to virulent TRT challenge. Using an in-house Elisa there was a satisfactory response (as compared to previous experience with eye-drop and spray) by 3 weeks of age. The next step was to test efficacy using antibody positive eggs and a low dose of vaccine (10^1 below normal). Injection was at 24 days of incubation. Challenge was conducted at 3 or 6 weeks of age. There was no effect on hatchability in this case. At 3 weeks both groups still had the same level of antibody. On challenge antibody negative eggs given low dose were fully protected, antibody positive eggs showed 77% protection. Further work was shown on the use of eye-drop vaccine at day old to provide protection for both type A and B challenge Summary: Inoculation of a high dose of live attenuated TRT vaccine did not affect hatchability and caused only mild clinical disease in a small proportion of poults. A low dose in antibody positive eggs provided 77% protection from challenge at 3 weeks.

Ref Number : 301
28. Jones, R.C., Worthington, K.J. and Sargent, B.A. Some observations on serological responses to avian pneumovirus in turkeys and chickens. TurkBerlin00 2000.
Keywords : pneumovirus; turkeys; Chickens; sub-types; elisa; vaccine; infections; Birds; immunity;
Notes : In the UK there are sub-types A and B and various commercial test kits based on Elisa. It is generally agreed that there is good cross-protection between types A and B. What do we expect from APV Elisas ? Ability to detect successful uptake of vaccine and seroconversion in response to field infection. We have direct Elisa's and competitive elisas and various antigens are used. There can be any combination of A's and B's in the antigen, vaccine, and field challenge. When birds are vaccinated with one type and challenged with the other there seems to be more consistent reactivity among different test kits. Chickens often do not produce a detectable response after vaccination or after challenge. It has been shown that IgA antibodies can be found in tears but not a lot in trachea. Turkeys are much more reactive than chickens to both attenuated vaccine and challenge. Currently Elisas are probably no good in chickens to determine response to vaccination, also may be misleading in diagnosis.There are differences in response between chickens and turkeys. We could think about double Elisas, bivalent Elisas, viral subunit Elisas or IgM specific Elisa to confirm recent infection. It would also be nice to have a simple test of cell mediated immunity.

Ref Number : 298
29. Engstrom, B. Appearance and disappearance of turkey rhinotracheitis in Swedish turkey farms - a case report. TurkBerlin00 2000.
Keywords : turkey; report; poultry; production; density; broiler; Denmark; elisa; PCR; disease; Newcastle; Newcastle Disease; infections;
Notes : Poultry production in Sweden is relatively low density, however it tends to be located in the south of the country. Two broiler parent flocks were affected in the south west close to Denmark - mild respiratory signs, low mortality - antibody detected by a blocking Elisa. APV type A detected by PCR in four flocks - determined to be type A. The index cases were in 2 different companies and all sera tested were strongly positive. Given that this was a new disease further investigation revealed 4 more infected flocks. A stamping out process was adopted for these 6 flocks and restrictions were put in place as for Newcastle Disease. Serological monitoring continued. It was difficult to find epidemiological links between the first 6 farms. A single turkey farm about 20 km from the broiler parent farms was also found to be positive although clinical signs were minimal - believed to have been affected much earlier - this site was multi-age and had an exhibition and processing plant with no biosecurity. There started to be a large number of farms detected so there was a change in policy - vaccination was allowed in broiler parents. The disease seemed to spread without identifiable contact over large distances. Strict biosecurity failed to prevent this. On some farm spread was very slow. Even though the turkey farm did not vaccinate the infection died out and were antibody negative in 1999. One broiler parent company stopped vaccinating and are antibody negative - the other still vaccinates because of possible new introductions.

Ref Number : 297
31. Nagaraja, K., Shin, H.J. and Halvorson, D.A. Avian pneumovirus of turkeys and its host range. TurkBerlin00 2000.
Keywords : pneumovirus; turkeys; elisa; veterinarian; economics; virus; Temperature; Chickens; Birds; disease; serology; PCR; infections; control; broiler; Ducks; Pigeons;
Notes : Avian pneumovirus has been present in the USA at least since 1997, when it was diagnosed in flocks from Colorado. Development of an Elisa test allowed screening and identification of its presence in Minnesota - some veterinarians believe it started in 1995 or 1996. There are a very large number of affected flocks and its economic effects are much greater than those of low pathogenicitiy AI. Biosecurity as applied has not prevented its spread. This particular virus appears not to affect the trachea to any extent - it is mainly in the turbinates and sinuses. This virus survives freeze-thaw cycles very well and at room temperature for 2 weeks. Even in a conventional freezer it will survive for at least 1 year. This is relatively resistant for a pneumovirus. The first question addressed was what is the host range. Most isolations in the literature are from chickens and turkeys - it has been innoculated into a broad range of species but only reisolated from chickens and turkeys. Antibodies have been found in guinea fowl, ostriches (Zimbabwe) and seagulls (Europe). This project examined mice, rats, waterfowl, wild birds, chickens and other birds - in Minnesota there is no evidence of disease or serology in chickens. Mice - 3, 5 7 week old inoculated with 10^4 TID 50 All age groups were PCR positive at 4,8,14 days post infection and seroconversion occurred by day 14. PCR positivity was found in droppings but not in bedding. When control mice were put in contact there were some lung and rectal swab positives. Similar results were found in rats although virus was present for a shorter period - they also seroconverted. Both rats and mice were laboratory strains Chickens - no infection established in SPF leghorn chicks. When conventional broilers were taken from the field at 14 days and infected orally or oculo-nasally most birds showed signs by 8 days post infection. A similar study on 2 week old ducks. Oculo-nasal challenge resulted in a broad range of PCR positivity between 3 and 21 days PI - blood,lung, trachea etc - similar results by oral challenge. This raised the question as to the role of migratory waterfowl in the transmission of APV - used sentinel ducks. On one pond they were positive within 1 week of placing (only positive from choanal and nasal swabs, not cloacal). (sero-conversion positive at 4 weeks) - now virus isolation completed. In a second site it took 8 weeks for the birds to go positive. Field samples from sparrows, starlings, swallows, pigeon, kill deer, not grasshopper, frogs, rats etc.

Ornithobacterium rhinotracheale

Ref Number : 305
24. Sommer, F. Detection of antibodies against Ornithobacterium rhinotracheale in Austrian turkey flocks by Elisa. TurkBerlin00 2000.
Keywords : Ornithobacterium; Ornithobacterium rhinotracheale; turkey; elisa; management; disease; broiler; layers; ART; ORT; Birds; turkeys;
Notes : Clincal signs are variable - an acute highly contagious, duration and mortality variable. It requires synergism with management faults and viruses. It is difficult to reproduce disease without use of a "primer". This survey includes 6 broiler parent flocks, 16 broiler flocks (all in lay),turkeys and layers (in lay). Half of the broilers were from sick flocks most of the rest was routine monitoring. Positivity: Sera FLock Broiler parents - 95% 100 Broilers 16% 47 Layers 100 In both broilers and layers there were paralel high ART titres. Ort titres and positive was higher in the sick broilers than in the normal birds. In turkeys 56% of flocks were positive in the Biocheck Elisa and 83% in the Idexx system. There were massive differences in reactivity among the 2 test systems. There is not a great correlation between clinical history and response to either test. Between test reproducibility within manufacturer is satisfactory but is very unsatisfactory between manufacturers. Possible causes are the antigen strains, methods of antigen extraction and judgement of suspect sera.

Ref Number : 304
25. Zorman, R.O., Zdovc, I. and Bencina, D. Ornithobacterium rhinotracheale - current situation in Slovenia. TurkBerlin00 2000.
Keywords : Ornithobacterium; Ornithobacterium rhinotracheale; Male; Female; broiler; pneumonia; egg drops; serology; pneumovirus; ORT; turkey; E.coli; enrofloxacin; Birds;
Notes : This paper describes outbreaks Flock 1 - 68 days old clinical signs of depression, weakness, gasping an sneezing. Morbidity was 50% in males, 20% in females - weekly mortality rate was of the order of 1% Flock 2 - 72 day old severe clinical signs in males - 3% mortality Flock 3 - 27 week old broiler breeders - depression, weakness, gasping mortality 1.7% in 10 days - fibrinopurulent pneumonia, aircsacculitis, no egg drop. Bacteriology - lungs, tracheas etc Serology for ND, AI, Pneumovirus, Ort by ElisaM.g. M.s. M.m. Ort was isolate from tracheal lungs and heart of the turkey flocks, E.coli was also commonly isolated. Isolates were sensitive to amocycillin, lincomycin, tetracycline but resistant to enrofloxacin etc. The affected flocks sero-converted to Ort but was also positive for M.s. Another unaffected flock was positive for antibodies to Ort and M.s. but went M.s. negative. A fourth unaffected flock showed low titres for Ort. The broiler parent case occurred in november and it is surmised that the problem was related to M.s., and poor ventilation. Ort antibodies are commonly present in imported broiler parent chicks. Presence of antibody in healthy birds suggests that this is a multifactorial problem.

Avian Influenza

Ref Number : 289
30. Capua, I, Mutinelli, F and Morneo-Martin, A. The 1999-2000 avian influenza H7N1 epidemic in Italy. TurkBerlin00 2000.
Keywords : Avian Influenza; veterinarian; poultry; production; Birds; Meat; turkeys; broiler; turkey; layers; disease; enteritis; feed; Chickens;
Notes : This epidemic has caused a massive amount of work for lab staff, epidmeiologists and field veterinarians. On march 29th 1999 H7N1 LPAI was isolated and notified. This circulated for 9 months in industrial poultry production. The first suspicion of HPAI was on December 13th, confirmed on the 17th. The last outbreak was notified on April 5th. The LPAI infected area was in Veneto and Lombardia, initially in the Verona area. In this area 250 million birds are slaughtered annualy - 10+ hatcheries and processing plants. The great majority of identified LPAI cases were in meat turkeys. Clinical signs - Broiler turkey breeder and layers - fever, depression, drop in egg production (up to 80% in turkey parents). The main PM finding was egg yolk peritonitis. Morbidity was 100%, mortality 2-20%. Abnormal shell colour and shape were common. Meat turkeys - birds under 40 days showed respiratory disease with marked sneezing, coughing, sinusitis, fibrin clots in the sinuses and trachea. In young birds haemorrhagic/necrotic pancreatitis was seen, often followed by enteritis. Mortality up to 97% occurred in young birds - swollen heads and sinusitis. In older meat turkeys and broilers it was milder, with severe loss of appetite, mortaliy generally of about 5% There were 413 outbreaks from December to April - mainly in meat turkeys (177) and layers (121) - the total number of birds affected (deaths/depopulated/preemptive slaughter) was about 17 million. There were a number of outbreaks in other areas, including 1 in Sardinia and 1 in Sicily - related to bird movements. HPAI clinical signs - Severe depression, no feed consumption, cyanosis of comb, occasionally haemorrhages on the shank (chickens), mortality approximating 100%. In caged layers there was slow progression in the house but birds died suddenly. Comments - LPAI should be diagnosed promptly in order to achieve a stamping out policy in a limited number of flocks. Improved biosecurity should be implmented at flock level. EU directive 92/40 which defines AI virulence should be extended to cover LPAI. After all of this everybody was ready for a holiday - now we have ND!

Ref Number : 299
33. Hess, M., Wenzel, R. and Hafez, H.M. epidemiological investigation on avian pneumovirus in poultry flocks using nested RT-PCR. TurkBerlin00 2000.
Keywords : pneumovirus; poultry; virus; serology; Birds; vaccine; PCR; turkey; epidemiology; sub-types; sequencing; genes;
Notes : This virus belongs to paramyxoviridae, pneumovirinae, Metapneumovirus is the proposed genus. Three sub-types have been identified to date. Initially types were based on differing serology. Sequencing of the glycoprotein gene allowed the development of PCR's Type B is currently dominant in the UK and, France, a non-a/non-b virus has been identified in France. The US virus is designated C. In this work samples were taken by practitioners from sick birds. Dried swabs were submitted for examination. Use of Nobilis and Tervac vaccines allowed comparison with field isolates of types A and B, though it was not possible to distinguish vaccine and field challenge. Of the flocks tested 31 samples were type A, This nested PCR detects up to 25 TCID50. TRTC is widespread - 60% of turkey flocks. 50% of non-vaccinated flocks were positive. Subtype A is the predominant strain type (92%)

Ref Number : 295
34. Pittman, M. The current EU legislation to control avian influenza as well at the future approach. TurkBerlin00 2000.
Keywords : control; Avian Influenza; Influenza; Human; disease; risk; infections; poultry; virus; surveillance; inspection; culture; report; Animal; disinfection; review; Birds; density; production; legislation;
Notes : For the adoption of legislation 2 procedures are used. Regulations have to be immediately applied, directives need to be put into national law and there is some leeway in their application. A more complex procedure is the co-decision procedure introduced by the Treaty of Mastricht and simplified by the Treaty of Amsterdam. This is mainly used for public health issues and requires 2 readings through the European Parliament. The standing veterinary committee meet twice monthly on veterinary and human health issues. Control and eradication of AI 92/40/EEC. Harmonisation was required because it is a list A disease, it can cause high losses and can affect trade - i.e. high socio-economic importance. Reduced border controls increase the risk of disease spread - now relies on checks at source rather than at destination. AI is defined as an infection of poultry with an Influenza A virus of IVPI greater than 1.2 or which have multiple basic amino acids at the cleavage site. When this occurs there is a stamping out policy for affected flocks and flocks with epidemiological/proximity links. When there is a limited outbreak a protection zone of at least 3 km is established - and surveillance of at least 10 km. A census is carried out then veterinary inspections, epidemiological enquiry with tracing, - restrictions on movement on poultry eggs, and manure. Movements may be allowed by authorisation. Restricted areas may be extended under the safeguard clause (90/425/EEC) which requires intervention of the SVC when control is not being achieved. The area may be defined on epidemiological and topographic (rather than political) boundaries. This may be applied to third countries and is in line with WTO and SPS requirements. Control measures favour stamping out. Emergency vaccination is allowed but the area affected is considered infected - trade restrictions apply. There are contingency plans to ensure compensation and resources to deal with a reasonable outbreak. Member states have national laboratories and there is a community reference lab which is a source of expertise, knowledge and training. Prompt diagnosis is required with harmonised rules for viral identification. There is characterisation of viruses and maintenance of culture collections and reagents. The Food and Veterinary office is based in Dublin and controls implmentation of EU legislation by member states and third countries. There are on-the-spot missions but concentrates of assessment of effectiveness of veterinary structures and their control functions. Its operations are transparent and reports are published on their web site. Financial support by the community - it is important in order to maintain farmer support - the community covers up to 50% of member states costs for destruction of animals, cleaning and disinfection and destruction of contaminated materials. Future approach - the definition needs to be reviewed on the basis of accumulated experience and taking into account the risk of mutation from low to high pathogenicity. The SVC has been asked to review the adequacy of the current definition, as well as what action is appropriate for low pathogenicity viruses. They have also been asked to review policies on emergency vaccination and surveillance - monitoring programmes and role of wildlife? General conclusions - a well-designed targeted programme with industry support would provide a useful early warning system, Conclusions - the industry needs to reassess the wisdom of producing birds in areas of high bird density. Structures for integrated production need to take into account disease control. A high level of biosecurity is required. Simulation exercises should be run to test readiness of the control systems. Dedication is required from all involved.

Ref Number : 291
35. Ortrud, W., Teifke, J.P. and Starick, E. Comparative studies of the pathogenicity of avian influenza virus isolates in chickens and turkeys. TurkBerlin00 2000.
Keywords : Avian Influenza; virus; Chickens; turkeys; disease; poultry; turkey; Birds; enteritis; genetics; Influenza; Germany;
Notes : Clinical severity of this disease in commercial poultry varies from assymptomatic to 100% mortality. The main factor affecting this is virus pathogenicity. Directive 92/40/EEC defines the disease as caused by an influenza A virus with an IVPI of 1.2 or more, or has multiple basic amino acids at the cleavage sites. It is vital to know the pathogenicity for chickens and turkeys, regardless of the source of the virus. Because SPF chickens are available these are used for IVPI testing. In Germany various isolates of LPAI viruses have been reported - these have IVPI of zero in six week old chickens in spite of high mortality in turkeys. Should the IVPI be done in turkeys? A range of isolates have now been tested by both methods including German and Italian isolates. The multiple basic amino acids were only seen in the 2 HPAI strains from Italy. The tests were done in 5 week old Big 6 turkey poults or SPF 6 week old Lohmann leghorn chickens. The method followed the method laid down in the directive - 0.1 diluted allantoic fluid injected intraveneously. Birds were examined for 10 days and scored normal, sick, very sick or dead (0-3). Results ALl H6 and H9 had an IVPI of zero in chickens - equivalent in turkeys ranged from 0 to 0.18 (3/5 non zero) - minor illness from which they recovered, typically starting at day 4. The most prominent pm lesion at the end was moderate pancreatitis, slight kidney swelling -lesions more severe in turkeys. Enteritis and tracheitis were more evident in the chickens. The LPAI H7 strain from Italy showed zero IVPI in chickens but 0.67 in turkeys, another showewed 0.19 in chickens and 0.63 in turkeys - all diseased turkeys had marked pancreatic enlargement with focal necrotic areas and associated haemorrhage. Kidneys were enlarged and very pale. Lesions were more severe in turkeys than in chickens. The turkeys which died had fibrinous tracheitis. The HPAI strains had very high IVPI in both chickens and turkeys (about 3) - some showed focal mycoarditis, occasional sub-epicardial haemorrhage etc. Conclusions - HPAI gives similar pathogenicity results in both chickens and turkeys. LPAI tend to show increased IVPI in turkeys. Turkeys are clearly more susceptible to influenza virus induced pancreatitis and nephritis, at least in the genetic lines commonly reared.

Ref Number : 294
36. Hafez, H.M., Prusas, C. and Lohren, U. Serological investigation on avian influenza A in meat turkey flocks in Germany. TurkBerlin00 2000.
Keywords : Meat; turkey; elisa; Swine; Influenza; Germany;
Notes : Fowl plague was first described by Perroncito in 1878 in Piemonte, Italy. There have been cases in Australia, England, USA, Ireland, Mexico, Pakistan, USA. After events in Italy the awareness of the turkey industry has increased in many countries. Voluntary investigations are ongoing. The German Turkey Producers association has been testing all meat turkey flocks since the middle of last year. A total of 533 flocks (10 samples/flock) have been tested. A commercial Elisa (IDEXX) has been used - positives are re-tested by HI for H5,H7 25 flocks (4.7%) are Elisa positive (147 samples - 2.8%). All except 1 of the positive flocks were from northern Germany. All positive samples were tested for H5 and H7 by HI and all were negative. 9/12 of the positive flocks were positive for H6. Sera tested and found Elisa positive in other laboraties were H6 positive also. Conclusions are that H5 and H7 are not circulating in Germany. There is some H6 and H1, it is believed that at least some of this is of swine origin.

Ref Number : 293
37. Starick, E. and Ortrud, W. Detection and characterisation of recent German avian influenza virus isolates by molecular biological methods. TurkBerlin00 2000.
Keywords : Avian Influenza; virus; PCR; turkeys; Germany; sequencing;
Notes : H9N2 viruses were isolated in Germany in 1995 and 1996. In the past 2 years most isolates have been various combinations of H6. This project aimed to develop molecular biological methods targeted at the haemagglutinin. PCR products were generated and cloned for sequencing. All isolates originated from turkeys in Germany in 1998 and 1999. Deduced amino acid sequences found greater than 98% homology.

Ref Number : 288
38. Halvorson, D. The control of avian influenza. TurkBerlin00 2000.
Keywords : control; Avian Influenza; chicken; disease; virus; Temperature; poultry; Swine; Birds; turkeys; infections; turkey; production; education; density; vaccine; risk; serology; Influenza;
Notes : We are now in a new era in influenza control. The Hong Kong incident with 18 people infected with HPAI of chicken origin with a 30% mortality rate has led AI to be reclassified as a zoonotic disease. This could raise food safety issues (in HK chicken consumption dropped 70%). It is agreed that the best control is to keep it out - where this is possible. Subtypes refer to the surface antigens, pathotype on pathogenicity - not all H5 and H7 ar HPAI. The virus can survive for a week at ambient temperatures, months in winter. This virus requires a dense population of susceptible hosts. It has a high mutation rate and its segmented genome facilitates natural recombination - potentially 255 combinations from any 2 viruses coinfecting a cell. There are other reservoirs to consider in addition to wildfowl - live poultry markets and swine. Minnesota has 10000 lakes and is the largest brooding area for wild waterfowl in the US. Live bird markets are mainly a problem in the eastern US - e.g. H7 in New York live bird markets for the past few years. The trick is to avoid commercial poultry becomming a reservoir. In Pensylvania in 1980's, Mexico and more recently in Italy when LPAI became established HPAI eventually emerged. All influenza is a serious problem in turkeys and the subtype does not really matter for this. HPAI can emerge (this has not happened in Minnesota). The author has seen 70% mortality in LPAI. There is no uniform control programme for LPAI. The Minnesota industry has decided that it must look for this infection, there must be an immediate and energetic response - don't worry about finding HPAI because federal government will be too slow to act anyway. If HPAI and LPAI are circulating simultaneously it is very complicated. Grower cooperation is key to all control programmes - the producers interest must be kept at heart, programmes should incentivate control. Since 1978 there have been more thatn 100 outbreaks in Minnesota, involving more than 1000 flocks. Every flock which is grown or processed is checked serologically. Each year there tend to be different subtypes from the previous year. "Live with the introduction" rather than "live with the disease". The worst outbreak was in 1995 - this and the HK incident has reduced range turkey production from about 10% to about 1%. The key points are to remember waterfowl, range growing, unclean load out equipment and personnel, partial flock removal, marketing of actively infected birds and inadequate cleaning and disinfecting - this is the basis of the Minnesota voluntary AI control programme. A major factor is to provide education to prevent exposure and spread - annual meetings, publications etc. We must keep in mind that turnover rates are often high (e.g. catching crews). Monitoring is required to allow responsible responses and appropriate vaccination. A responsible response - concentrates in not causing inadvertent penalties - asking to slaughter involuntarily encourages non-reporting. The best thing to do for an infected flock is to delay marketing until after the acute phase then progress to orderly marketing. Scheduling of new stock onto the farm needs to be modified. Spread reduction measures must target specific, most important people (those with direct contact with the flock and its manure). Catching crews and equipment are the main issue. Brood and move is normal so this move is a good way to spread disease. What is appropriate vaccination : killed injectable, aiming to reduce the susceptible population where biosecurity is not enough (where there is area spread due to high farm density) . It is unlikely to be overused because of the difficulty - its important that it be of the right type. Problems - as there is no compensation programme - lack of a vaccine might encourage intentional infection (e.g. in breeders). Effective vaccination reduces the numbers of susceptible birds, reduces the number of infected birds and the quantity of virus shed on challenge (by 99%). Lack of a vaccine can cause financial disasters. USDA and EU have expressed concerns about vaccination and it will not prevent infection or transmission. However laboratory studies that it reduces it substantially. Field results with approved vaccine in the USA has not been associated with any homologous failures. Vaccination crews are a risk but so are all crews. - it is a manageable risk. Serological titres are indistinguishable - so are they for ND - serology is identical for LPAI and HPAI. Vaccination does not protect against transmission - this is largely theoretical. "Use of vaccine sends the wrong message" - is it preferable to allow LPAI to circulate freely? In Minnesota - 45 million turkey population - only 1-5% are vaccinated each year. The Utah 1995 outbreak demonstrated the benefit of an effective vaccine. Lessons : Vaccine should be a first resort not a last resort. Suggestion - conditional licensing, controlled use, must be inactivated. Killed vaccines are not a threat if used as part of an integrated control programme - the advantage of reducing circulation of LPAI far outweighs any disadvantages. If international agreements are a problem we should change them. Serological monitoring relies exclusively on the AGP test.

Ref Number : 287
39. Alexander, D.J. and Gough, R.E. Avian Influenza in turkeys. TurkBerlin00 2000.
Keywords : Avian Influenza; turkeys; review; disease; Birds; Human; virus; poultry; surveillance; density; turkey; production; Ducks; infections; egg drops; Pasteurella; vaccine; control; feed; Pig; Influenza; legislation;
Notes : This paper will review this disease in turkeys.Influenza type A affects both birds and a broad range of mammals (esp humans, pigs, horses), type B have been isolated from humans (recently from seals) and type C have only been isolated on rare occasions in humans or pigs. Influenza A virus are classified according to their 2 major proteins, haemagglutinin (15 types) and neuraminidase (9 types). All types have been found in birds, in humans mainly types 1-3. Many years ago it was recognised that there was an association between waterfowl and avian influenza. Much of the early work was done in Canada and this demonstrated association between migratory wildfowl and respiratory disease in poultry. Surveillance showed a high proportion of samples, especially from juveniles, to be positive for influenza viruses.. They have also been identified from psittacines in quarantine, but mainly mallard (18.9%) and anseriformes (15%). Waterfowl can occur at high density, especially on lakes on migratory flight paths. Turkey production tends to be concentrated in particular areas. In California and Minnesota there is overlap of high concentrations of poultry and waterfowl. Sentinel ducks show that isolation of AI in north america is seasonal and matches wildfowl migration. The same subtype tends to be dominant in both waterfowl and commercial turkey flocks. These findings encouraged the housing of commercial turkeys in North America. There are 2 pathotypes of influenza in poultry - low pathogenicity induces mild respiratory disease, depression, egg production problems and may exacerbate other infections. High pathogenicity is associated with severe disease, usually only H5 and H7 subtypes, mortality close to 100%. In practice, in the field it can be difficult to distinguish between the 2 types because of high mortality in LP cases due to other diseases. In LP infection there are a variety of factors affecting severity - the virus, host age (younger birds more affected), and other pathogens. LPAI occurred in GO in 1979 - it affected 50 week old birds H7 showed only mild respiratory disease - in various other cases there were white egg shells, mishapen eggs, marked egg drops, sometimes low mortality. Use of a live Pasteurella vaccine at the time of challenge resulted in 10% mortality on 2 weeks in one case in the USA. HPAI cases are relatively uncommon, only about 18 index cases recorded since 1959 - equal numbers of H5 and H7 in turkeys, more H7 overall. There were as many cases in the 1990's as in the previous 30 years - an emerging problem? HPAI in turkeys - sudden high mortality, up to 100%, cessation of egg laying, respiratory signs, oedema and cyanosis of the head, haemorrhages in tissues, neurological signs. Control - the most effective method is to prevent the virus entering a country, area, farm and flock. This is easier to achieve in island countries. Legislation covers issues such as vaccination, slaughter policies etc. On the farm the main options are prevention of infection and vaccination. Farm biosecurity : planning and design - all commercial farms and flocks should be well separated, hatcheries should be isolated from farms, separation of species by farm, ensure adequate fresh water (not surface water). Basic house biosecurity should include bird-proofing of houses, stores, water tanks, movements on and off farms should be controlled, visits between different farms should be carefully controlled. - vectors are caretakers, farm owners, staff, feed lorries, hatchery vehicles. etc. AI vaccines have been formalin or BPL inactivated vaccines in oil emulsions.

Ref Number : 290
40. Valentina, A.D., Fabris, G. and Gavavzzi, L. Avian Influenza H7N1 in broiler breeders and meat turkeys in the north area of italy: clinical and serological investigations. TurkBerlin00 2000.
Keywords : Avian Influenza; broiler; Meat; turkeys; Birds; turkey; production; elisa; feed; egg drops; Influenza;
Notes : Influenza viruses have been found repeatedly in various avian species in Northern Italy over the years, 1970's, 1980's, 1994, 1997. Current series started in March 1999. Inappetance was the most marked sign, also paralysis, gasping, sinusitis, sc emphysema, pus in sinuses and the syrinx. In broiler parents flaccid ovaries, and tracheitis were associated with peritonitis. In commercial turkeys mortality was highest in birds of 20-60 days - on average morality was 10% above normal for all affected flocks. One case in turkey parents affected at 32 weeks of age resulted in a marked drop in production which persisted for the life of the flock. In commercial turkeys HI titres were 1:16-1:128 Elisa tests were very sensitive - titres of around 1100. The problem also reduced feed conversion by 200 grammes, reduced weights at slaughter by 1.5kg, and increased condemnations by 3% - egg drops ranged from 30 to 60% HPAI Devastating effects with almost total losses, direct estimated damage is estimated at 210 million Euros. It is proposed that all H5 and H7 viruses should be considered potentially highly pathogenic.

Ref Number : 292
41. Mutinelli, F., Capua, I., Bozza, M.A., Grossele, B. and Furlattini, V. Comparative intraveneous pathogenicity for turkeys and chickens of the low pathogenic avian influenza A/ty/Italy/3675/99. TurkBerlin00 2000.
Keywords : turkeys; Chickens; Avian Influenza; Meat; chicken; turkey; Birds; control; Feathers; growth; enteritis; virus; Incidence; Influenza;
Notes : LPAI faced Italy from March to December 1999 - 199 outbreaks of which 164 in meat turkeys - a severe condition in meat turkeys which led people to question the validity of using the chicken test data. This project aimed to compare the results of IVPI test performed in chickens and turkeys. 22 SPF chicks and commercial turkey poults were divided in 4 experimental groups of 11 birds each. They were tested for seronegativity at 4 weeks for a range of pathogens. Inoculation was in accordance with the directive at 4 weeks of age.- 1 control group and 1 inoculated per species. Birds were examined daily for clinical signs and sacrificed at intervals. Birds were necropsied and selected organs were collected for virology, histology and histochemistry. Infected poults develped a clinical condition characterised by depression, anorexia, ruffled feathers, diarrhoea and this resulted in marked stunting growth while infected chickens remained healthy. The gross lesions were of an acute haemorrhagic-necrotic pancreatitis proceding to fibrosis and atrophy. There was enteritis and mal-absorption as well. Virus was isolated up to day 5 p.i. Influenza A antigen was demonstrated by immunohistochemistry of the pancreas using the commercial "EnVision" system. In chickens virus was isolated only until day 2 p.i. There were low incidence lesions of pancreatitis and nephrosis in chickens. Histochemistry was much more commonly positive in turkeys than in chickens Conclusions - LPAI strain used appears to replicate much more effectively in turkeys than in chickens, the pancreas is a particular target.

Miscellaneous

Ref Number : 285
1. Szolgyenyi, W. Diagnosis of avian mycoplasmosis by PCR and internal positive controls. TurkBerlin00 2000.
Keywords : PCR; control; serology; culture; Sensitivity and Specificity; Mycoplasma; turkey;
Notes : From the University fo Vienna - using PCR for supplementing the traditional approaches to diagnosis (Serology and Culture). PCR provides high reliability, both respect to sensitivity and specificity - economical as well. The MG product of 16S rRNA covers 186bp - separatedy by pulsed gel electrtophoresis, stained by ethidium bromide. PCR can also have problems of false positives and negatives, e.g. laboratory contamination of previously amplified products, or on the other hand inhibition of taq polymerase. To achieve a detection level usually about 30 cycles are required. Inhibition can grow also with increasing cycles. Remember that reference strains are very clean with no inhibiting materials. PCR optimization - inclusion of positive and negative controls. Trials were carried out to determine the optimal concentration of an IPC internal control.

Ref Number : 284
4. Gazdzinski, P. and Hunter, B. Hypothyroidism in turkey breeder candidate hens. TurkBerlin00 2000.
Keywords : turkey; Birds; Liver; biochemistry; control; disease; feed; Temperature;
Notes : Description of syndrome - hens affected at 22 to 30 weeks of age. Hens loose balance and flip onto their back in the dark period. Most die after a couple of days - over an 8 week period is 1-1.5% - highest in the winter months house temperature under 50 F. Morality rises steadily from 23 to 29 weeks. When they come into lay the problem disappears. In this work PM's were conducted on live and dead affected birds along with detailed biochemical and hormonal profiling. Also did hormone profiles of experimentally stressed (flipped over) hens, as well as thyroid stimulation testing, histology and immunohistochemistry. Initially there were no significant lesions on routine necropsy, histology, bacteriology, virology. Affected birds tend to be heavier than normal (also increased liver size and abdominal fat). Surviving flipped-over hens are losing weight during the period in question. There were no significant effects on blood gases. Biochemistry profiles showed many differences - sodium, potassium,chloride, blood protein low, uric acid and ketone bodies were high. However it is now believed that these effects were due to hens lying on their back. "Fresh flipovers" showed no significant effects on these parameters. Thyroid hormones were 277 pcg/ml in affected hens shortly after flipping, compared to 900+ in controls (T3). A similar pattern was seen with T4 - recovery to similar levels after a couple of days. Flipping birds experimentally increased corticosterone 3 times but had no effect on thyroid hormones. Histology showed variable intensity of colour of matrix in the thyroid, degenerate follicles, sloughing of epithelium, and an acute or chronic thyroiditis - mainly lymphocytic infiltration. TSH stimulation testing showed a response for T3 and T4 but levels were much lower than for normal hens. Is this an autoimmune disease? Preliminary immunohistochemistry has not revealed turkey antithyroid antibodies. Detected changes initially were result of anorexia, and dehydration/stress. The underlying disease is a thyroiditis associated with low thyroid hormones and poor response to stimulation. This problem has been seen to date only in BUT birds, not Nicholas and Hybrid, at least as seen in this company to date. The problem has not been seen in commercial birds. The problem does not seem to be response to increasing levels of iodine in feed. Water sanitation with iodine may be the next step.

Ref Number : 283
5. Panshin, A., Shihmanter, E., Weisman, Y., Orvell, C., Kydyrmanov, A., Sayatov, M., Asanov, M., Nyaga, P.N. and Lipkind, L.M. Comparative antigenic characterisation of Newcastle disease virus strains isolated from turkeys and chickens. TurkBerlin00 2000.
Keywords : Newcastle; Newcastle Disease; disease; virus; turkeys; Chickens; poultry; vaccine; turkey; chicken;
Notes : Newcastle disease is a devastating viral disease of many avian species, that can lead to substantial losses in poultry. It is caused by paramyxovirus, both chickens and turkeys are affected. In general it is felt that vaccines are more effective in chickens than in turkeys. This work seeks to compare the antigenicity of various ND strains isolated from chickens and turkeys. A bank of monoclonal antibodies were developed against Haemagglutinin, F protein and structural protein. These MAB's bound to 20-96% . Schematic models were derived from the results suggesting the relationship between the various epitopes. Most binding patterns were isolated from both species. On dendrograms turkey and chicken strains were quite intermixed.

Ref Number : 280
6. Faye, I. Intensive turkey production with a particularly animal-firendly housing system. TurkBerlin00 2000.
Keywords : turkey; production; poultry; Meat; turkeys; Free range; broiler; density; feed; Female; Male; Antibiotics; growth; Birds; Swiss;
Notes : Optigal is a main poultry producer in Switzerland - turkey meat consumption is very low, production is only 45 t/year. This company has been in turkeys since 1987, free range turkeys in 1998, is ISO 9001 and ISO 14001 certified. Produces 13 million broilers, 60% free range, 350000 turkeys, all free range. Use T9 imported as day-old - rear on deep litter in whole-house brooding - houses are equipped with roosts, no debeaking with daylinght via windows. Legally 5 lux, in practice 15 lux, minimum 8 hours consecutive night. Density is 36.5 kg/square metre - there are patios and yards (available after 43 days - the end of quarantine). Feed is expanded and contains only vegetable protein, no GMO or GP's Females are killed at 3-4 kgs and males at 7-9 kg. Losses are decreasing, typically now 6% in males, 3% in females, antibiotic treatments are reduced on free range. There has been now obvious changes in growth rate, slight increases in FCR. Production of free range T9 turkeys is feasible and improves welfare - no specific problems are noted. Flocks are 2200 birds, half male, half female (in accordance with Swiss law).

Ref Number : 279
7. Prusas, C. and Hafez, H.M. Investigation on avian leucosis in commercial turkeys. TurkBerlin00 2000.
Keywords : leucosis; turkeys; Chickens; production; virus; Meat; chicken; Liver; ALV-J; layers; culture; turkey; infections; elisa; broiler; Germany;
Notes : Avian leucosis is the commonest B cell lymphoma of chickens - associated with tumour production and reduced productivity. Exogenous virus induces new infectious virus in susceptible host cells - subgroups A,D and J are most common. Endogenous virus (subgroup E) is integrated in the genome of chickens. ALV-Subgroup J is a new subgroup first identified in the UK in 1989 - it was associated with tumours and production problems in meat type chicken breeders. There is evidence of increasing virulence. Infection causes typical myelocytomas in liver, spleen, bones. ALV-J appears to be a recombinant between exogenous and endogenous ALV's. It is able to propagate in cells resistant to subgroup A and E virus. Its main difference is increased horizontal transmission and increased pathogenicity in meat-type chickens (less in layers, opposite situation for subgroup A). The target is myelocytes rather than B cells. Avian species vary in susceptibility to sub-groups (based on avian fibroblast cultures) - turkey cells are susceptible to all types. This led to interest in investigating the presence of this infection in turkey farms. Breeding and meat turkey flocks were examined by P27 Elisa for antigen and GP85 for antibody - all of 16 flocks were negative in both tests. In further work a very low positivity of antibody (0.7%) of 417 samples from 39 turkey flocks. Equivalent figures for layers was 1.3% and 16.6% for broilers. These reactions could be non-specific. Reactions are insignificant in turkeys at present in Germany, though there is evidence of its occurrence in broilers.

Ref Number : 282
8. Buda, S. Foot pad lesions and the influence of biotin in turkeys. TurkBerlin00 2000.
Keywords : turkeys; density; management; Antibiotics; layers; Birds; electron microscopy; Male;
Notes : Foot pad dermatitis is very common in growing turkeys - they are at least uncomfortable and may be painful. What are the factors ?- stocking density, type of litter and its management, water system, and possibly biotin. According to the literature the requirement is 275-325 mcg/kg. There are differences in bioavailability in accordance with the raw material. There may be interactions with drugs (antibiotics). Symptoms of deficiency are dermatitis or cracking of foot pads. Avian skin has no skin clands - composed of lipid-rich sebokeratinocytes - responsible for the synthesis of keratoproteins and lipids in multi-granular bodies. Layers are Stratum Corneum, Stratum Transitivum, Stratum Spinosum, and. Lipid deficiency causes structural changes - elongation of reticulate scales, proliferative hyperkeratosis, decrease in cytokeratin filaments, etc. Experimental birds (10/group) were supplmented with either 2000 mcg biotin or 300 mcg per kg. Methods used were light microscopy, electron microscopy. There were no differences between the groups with respect to gross lesions - there were marked differences on electron microscopy and light microscopy (less distinct than in clinical biotin deficiency) - surfaces much smoother in supplemented birds. Summary - 4 differences - morphology of reticulate scales, size of dermal papillary layer, Most commercial flocks suffer from foot pad lesions. Sufficient biotic is necessary to prevent skin lesions. 300 mcg/kg is probably not optimal, especially for male turkeys.

Ref Number : 277
9. Foulmann, A. and Glunder, A. Induction of a humoral immune response after the immunisation of turkey poults using an inactivated Bordetella avium vaccine. TurkBerlin00 2000.
Keywords : turkey; vaccine; consumer; Antibiotics; elisa; disease; infections; immunity; IgG; Birds; serology;
Notes : How can we respond to consumer demands to reduce use of antibiotics - immunisation. Can we achieve specific protection ? It is proposed to use inactivated vaccines to protect poults between 3rd and 6th week of life. Bordetella avium was chosen because the bacteium was available, a commercial Elisa test is available and it has disease significance. The literature suggests that infection or vaccination of turkey hens allows protective maternal immunity for 3 weeks. Infection of turkey poults results in a detectable serological response (IgA, IgG, IgM) - some experiments have also been done with vaccines. Materials - B.avium, ATTC 35096 10^10 CFU/dose formol inactivated 0.5%, and incomplete Freunds adjuvant. - 2 concentrations .2 ml and .5ml dose. The birds were Big 6 bought at 1 day old. Serology was conducted with the KPL kit. Application was s/c in leg 0.2 ml up to 14 day, and 0.5ml up to 21 days. Various ages and combinations were used. Sera were collected weekly and stored. Results were similar in all groups - antibody response increased on day 28 and peaked at 48 days (15-3000 titre). In each group the response was homogeneous. Two applications resulted in a slightly more rapid response but peaks were similar regardless of the schedule (not statistically significant at 42-56 days, some differences at 28-35 days. Conclusions - administration of inactivated B.avium vaccine applied before 21 days of age is immunogenic - 2 doses increases antibody more rapidly. The serology to date is based on IgG Elisa - the authors plan to look at agglutinins and examine effects of various adjuvants.

Ref Number : 278
10. Voelckel, K., Redmann, T., Bertram, E., Neumann, U. and Kaleta, E.F. Marek's disease in fattening turkeys: Clinical signs, pathology, detection of causative agent (MDV serotype 1) by PCR. TurkBerlin00 2000.
Keywords : Marek's; disease; turkeys; PCR; infections; virus; Birds; Chickens; serology; elisa; rev; culture; Liver; Germany;
Notes : Turkeys are known to be susceptible to experimental infection. Similar field disease has been identified, but the virus involved is rarely identified. This work relates to 4 sites, 2 very small , 1 with 150 birds and 1 700/crop. It is believed that all 4 had contact with chickens and/or other domestic or wild birds in early life. The 2 larger sites were multi-species. There was no direct contact between the farms. Virology was conducted with CEF and CEKC, serology by VNT, AGP (HVT, MDV_1) and Elisa (REV, REV). Histology of spleen was also counducted. PCRs were conducted on tumour and buffy coat cells for MDV-1 (132-bp repeat), REV and LPDV (proviral LTR). Clinical signs in affected turkeys were non-specific. Older birds often died with no obvious signs, some lesions were detected at slaughter. Livers may have obvious tumours or be generally enlarged, spleens can have one large or many small tumours. Histology shows pleomorphic infiltration with mainly mononuclear cells. Only HVT was detected in cell culture systems. All tested birds had HVT SN antibody. MDV AGP was negative. The PCR identified the presence of oncogenic MDV 1 in all 4 farms. Conclusions - turkeys are susceptible to MDV-1 and develop tumours. We do not know why infected turkeys become persistently viraemic and develop disease. So far only small populations under non-industrial farming conditions are affected in Germany. Circumstantial evidence suggests lateral infection from MDV-1 infected chickens.

Ref Number : 276
11. Kin, E. and Samberg, Y. Use of multicomponent vaccines against turkey diseases. TurkBerlin00 2000.
Keywords : vaccine; turkey; disease; turkeys; Newcastle; PMV; ORT; serology; control; elisa; Birds; Pasteurella; immunity;
Notes : Efficient vaccination programmes play an important part in the prevention of turkey diseases. In Isreal turkeys are vaccinated against Newcastle Disease, PMV 3, Yucaipa, AE, ORT, Erysipelas etc. All inactivated vaccines are adminstered by individual IM injection. By combining vaccines it is possible to reduce handling. Four multivalent experimental vaccines were produced, ND+HE, ND+PMV2+PMV3, ND+Pasteurella, Ort+Pasteurella. Titres are quoted in the abstract. Safety tests were carried out with 10 susceptible turkeys, 10 doses/bird, and observed for 21 days. Most vaccines were applied to commercial flocks at 21 or 28 days and evaluated by subsequent serology. Control groups were not included in field trials - serology was HI for ND, PMV2 and PMV3, Elisa for Ort, and immunodiffusion for HE. Birds were also challenged with ND, Pasteurella and HE. ND-HE combinations showed a good serological response and challenge protection. The trivalent PMV1-3 vaccine showed a good response for all serotypes but in most cases ND titres were higher than for PMV2/3 - there was satisfactory immunity post challenge. The ND/FC vaccine was also effective in serology and challenge studies.

Ref Number : 274
12. Kaiser, P. and Shelly, L. Developing turkey reagents: Cytokines and cell surface markers. TurkBerlin00 2000.
Keywords : turkey; markers; immunity; chicken; production; growth; macrophages; T cells; Human; elisa; virus; Chickens; assay; turkeys; IgG; infections; TRT;
Notes : The acquired immune system may be split into cell mediated and humoral immunity. Both systems are controlled by cytokines, different cells for each system. Knowledge of the system was originally acquired in mammals. Data to date on the chicken suggests that it is similar, in the turkey less is known for lack of reagents. This project was financed by BTF and aimed to produce turkey cytokines and then look at their activity as adjuvants and immune modulators (not covered here). This talk will cover production and characterisation as well as the basic reagent work. Previously only IFN gamma and type 1 IFN had been characterised in turkey. It is pleiotropic and active in most stages of the immune response, stimulates activation and growth differentiation of T and B cells, macrophages, natural killers and also epithelial cells - it is produced by NK and T cells. The C-DNA for IFN gamma was cloned - there is only 30% identify between chicken and human molecules - though much of the structurally imporant parts are similar. Chicken and Turkey IFN gamma are 97% identical. The prediction was that they would cross react. A capture elisa for IFN has been developed in Belgium - experiments used splenic cells stimulated by mitogens. Turkey splenocytes produced IFN gamma detectable in the same system. This work went on to look at recombinant IFN gamma - production was assayed by a macrophage/nitric oxide bioassay. Both recombinant chicken and turkey IFN gamma stimulated NO2 production by macrophages. A turkey virus was based on a continuous turkey cell line stimulated with CM for 48 hours. Both chicken and turkey r-N gamma was detectable in this system. The activity could be neutralised by monoclonal and polyclonal antibodies against IFN. This work will be published later this year. Interkeukin 2 - stimulates growth and differentiation of many cells involved in immune response, - stimulates expression of other cytokines and is produced mainly by TH1 cells. The DNA of turkey IL-2 was cloned using turkey-specific primers and genome walking. Again the identity with human IL2 was only 30%, chicken and turkey commonality was 84% but only about 70% in amino acids. In spite of this the main structure appears to be reasonably conserved. Knowledge of the mammalian molecules helped identify receptor structures, some are conserved between chickens and humans, some not. The prediction based on this was that chicken and turkey IL2 would not cross react. Tests were conducted in various assay systems, e.g. chicken splenocytes stimulated by ConA - in all assays there was a high degree of cross-reactivity. However it is possible to produce monoclonal antibodies which neutralise the bioactivity of chicken IL2 and not turkey IL2. Reagents Do existing chicken reagents cross react with the turkey reagents - this knowledge would speed up work on turkeys. Chicken reagents - antibodies to CD3, CD4, CD8, CD28, TCR and some others. Flourescent-activated cell sorting was used - binding anti-chicken CD4 attached to an anti-mouse IgG and a flourescent marker. Summarising the data - CD4. CD8, CD28, and some TCR, Bcell and anti-macrophage showed good reactivitiy for at least some monoclonals. Further work was carried out to confirm that these response were specific (i.e. same epitope on same molecule). Some infection studies have been carried out on TRT showing virus levels in infected levels (including quantitative RT-PCR) and hope to present this next year. There are influxes of successive T-cells into the Harderian gland - showed immuno-peroxidase sections.

Ref Number : 275
13. Sharma, J.M. and Silke, R. Role of cytokines in haemorrhagic enteritis in turkeys. TurkBerlin00 2000.
Keywords : Haemorrhagic enteritis; enteritis; turkeys; adenovirus; control; colisepticaemia; infections; virus; T cells; growth; intestine; macrophages; Birds; production; turkey; sheep;
Notes : HE is caused by Type II avian adenovirus - at one time caused major losses and is now under control through vaccination. Infected turkeys show splenomegaly and intestinal haemorrhages. Mortality may be 1-60%. Its main problem is immuno-suppression, death often is through colisepticaemia. Splenic enlargement is obvious at about 4 days post infection - typically 100%+ increase in weight. The virus seems to replicate in IgM bearing cells - these drop to a trough at day 4 and stay lower than controls for at least 20 days. Culturing in sorted cells showed that there was no activity in T cells and growth was greatest in the IgM bearing cells. In the intestine there is considerable destruction of tissue but very little viral expression - low level of virus is found in minimal (Background) levels in bursa, duodenum and thymus, much more in caecal tonsil, and most of all in spleen. Why is there so little virus in the affected intestine? It was hypothesised that although it replicates in B cells (possibly macrophages) - perhaps T cells are stimulated to produce cytokines (e.g. TNF) which cause the gut damage. There is evidence that CD4 cells increase in the acute phase, also T cells in the spleen seem to be transiently less responsive to mitogen. If the T cells are involved in the gut lesion can we moderate it by moderating T cell activity with cyclosporin A. CsA have reduced response to ConA after cyclosporin treatment, though there was no effect on their ability respond with antibody to sheep RBC and B. abortus. In the preliminary experiment gut lesions were reduced from 50% to 0 (10 birds per group) but had no effect on virus titre in spleen or splenomegaly. No inducing factor was shown to be markedly increased in spleen cells from virus infected birds treated with ConA. IL6-like factor and TNF production were similarly increased. It is suggested that the intestinal lesion is mediated by cytokines produced by T cells and macrophages, probably mainly TNF (thalidomide inhibits response). Further works needs to be done to characterise the details of the cytokines involved. The main lesions are in the duodenum - suggested that the duodenum is the target for the shock syndrome in turkey.

Ref Number : 308
16. Heinen, E. and Pirro, F. Enrofloxacin and difloxacin in turkeys: In vitro activity and pharmacokinetics. TurkBerlin00 2000.
Keywords : enrofloxacin; turkeys; enzymes; E.coli; Birds; Salmonella; report; resistance; chicken;
Notes : Enrofloxin and difloxacin are fluoroquinolones which act on DNA gyrase enzymes. Enrofloxacin was the first fluoroquinolone developed exclusively for veterinary use. Its efficacy has been widely documented. Recently difloxacin was approved. There are no published comparative data. There are small differences in structure, however these have considerable effects on activity. In the in-vitro studies both E.coli isolates obtained from healthy birds at slaughter and those from clinically sick flocks were used. Clinical isolates showed a range of mic's - 0.004 to 64 for enrofloxacin, and 0.015 to >128 for difloxacin. There is a trimodal distribution of sensitivity suggesting a number of mutations - not surprising given that it is likely that some will be from treated flocks. For both E.coli and Salmonella the MIC's for Difloxacin tended to be 2 dilutions higher. In Salmonella there appears to be a bimodal distribution. There have been reports from the UK of Salmonella resistance to Naladixic acid - it is not entirely clear how this relates to fluoroquinolone resistance and the role for clonal spread. When examining the E.coli isolates from healthy birds there is a townward trend in mean MIC's The equivalent chicken data have been published. Pharmacokinetics - used BUT Big 6 - 1200-1500 g with n=4 per sampling. Commercial products were administered either as a single oral dose or continuous medication over 3 days. Both drugs were rapidly absorbed - peak 0.9-2 mcg/g in enrofloxacin while 0.7-0.85 in difloxacin. There is 100% + tissue concentration in enrofloxacin but only 10-15% in difloxacin. Difloxacin depletion also occurred much more quickly. With continuous medication peaks of .6-1.2 occurred rapidly - steady state 0.5, equivalent for difloxacin was about .4-.6 and steady state less than 0.2.

Ref Number : 309
18. Irion, T. Turkey coccidiosis: Experiences with Toltrazuril. TurkBerlin00 2000.
Keywords : turkey; Coccidiosis; toltrazuril; eimeria; Chickens; turkeys; Geese; Pigeons; immunity; risk; control; anticoccidial;
Notes : Toltrazuril is a triazine trione formulated in trithanolamine and highly soluble in water. It has been shown to be effective for all important Eimeria species of chickens, turkeys (adenoides and meleagrimitis) also geese, pigeons, etc. Rapid elimination of the parasite is due to the high efficacy against all intra-cellular stages. It achieves this without inhibiting development of immunity - perhaps because the trophozoites and merozoites are not affected (allowing docking responses) and because the dead parasites can be detected in cells for a number of days. Immunity, depending on timing of treatment, may be enhanced. Toltrazuril may be used strategically at periods of high risk (e.g. around 28 days). Results of field trials in France were conducted with administration of Toltrazuril at start of clinical signs. Most flocks had recovered by 4 days post treatment - judged by clinical signs and lesion scores. A comparative study between different compounds carried out in 1991 was presented to show improved oocyst excretion control and weight gain of toltrazuril compared to potentiated sulphonamides. Treatment with toltrazuril 2 days before the HE vaccination appears to reduce vaccinal reactions - even in addition to the normal in-feed anticoccidials improved weights by 200 g and improved FCR by .02 - this more than paid for the cost of medication. For successful water medication the dosage should be calculated on the basis of mg/kg liveweight. 7 mg/kg is the minimum dosage in turkeys.

Ref Number : 296
32. Mulling, C. Structure and function of the respiratory system in poultry. TurkBerlin00 2000.
Keywords : poultry; Birds; Heat; Air; infections; turkey; Animal; anatomy; respiratory system;
Notes : We start our journey with the nasal cavity, entering via the nares which may be partly occluded by an operculum. There are three conchae, anterior, medial, posterior - the anterior surfaces are covered by stratified squamous epithelium. In the middle area the conchae are covered by ciliated epithelium with unicellular glands (typical of the respiratory system) - a transverse section will show the infra-orbital sinus. A traverse section in the posterior part will show the caudal chae and it is covered by olefactory epithelium (area is proportional to sense of smell). Lateral to this is the nasal gland, important for salt excretion in marine birds. The nasal conchae have a heat exchange function and recover 70% of the moisture in the expired air. The infraorbital sinus is susceptible to infections and inflammations - it is a triangular cavity and is only covered by skin laterally. Functions of the nasal cavity are Filtration - cleaning of inhaled air, olfaction thermoregulation - heat and water exchanging system. The larynx consists of 4 cartilages and is connected in front to the hyoid bone and the back to the trachea. Birds have a long and relatively thick trachea compared to mammals of the same bodyweight. Cartilage rings overlap alternately above and below. The cavity is covered by respiratory epithelium although there are many more and larger epithelial glands so more mucus is produced. In birds the voice is produced by the syrinx- a very complicated structure composed of modified cartilaginous rings connected with lateral and medial elastic membranes. In the middle is the Pessalus which is covered in cornified epithelium. The tension of the membranes is regulated by the syrngial muscles with resultant modulation of voice. There is a complicated system of bronchi in birds which are named according to the direction in which they run (e.g. medial-dorsal). The parabronchi are an anastomising system of airways connecting the secondary bronchi. Infundibula and atria connect the parabronchus with air capillaries which are closely associated with the ccirculatory system. The blood gas barrier is similar in structure to mammal but only half as thick - the diameter of an air capillary is 10% that of a mammalian alveolus. There is a counter-current exchange system in which airflow and blood flow are in different directions. In addition there are the air-sacs - bellow-like structures. There are the cranial and caudal groups - in the turkey the cervical clavicular sacs have fused so the total is 7. There is a simple squamous epithelium and there is no air exchange. On inspiration and expiration air always goes through the parabronchi in the same direction. The thoracic cage works as a pump handle. The overall effect is of a highly efficient gas exchange system - the most efficient of all air breathing animals.

 

 

Enquries relating to proceedings and future meetings:

Prof. Dr. H. M. Hafez

Institute for Poultry Diseases,

Free University, Berlin, Koserstr. 21, 14195 Berlin, Germany

   Tel  +49 – 30 83853862

  Fax  +49 – 30 83855824

E.-mail : hafez@zedat.fu-berlin.de