Download Australian Veterinary Poultry Association Meeting , Melbourne

January 15, 2018 | Author: Anonymous | Category: , Science, Health Science, Infectious Disease
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Meeting of Australian Veterinary Poultry Association (AVPA) and Commercial Poultry Veterinarians , Melbourne, 3rd&4th November 2011 50th Anniversary Meeting Opened by Nobel Laureate Dr. Peter Doherty

Tom Grimes

Dr. Peter Doherty • Only veterinarian to receive the Nobel Prize • Worked at Qld. DPI Animal Research Institute Yeerongpilly from 1963-67 after graduating from Uni. Qld. in 1962 • Obtained a MVSc on Leptospirosis of Cattle • Published on Infectious Bronchitis (IB) – Doherty, P. C. (1967). Occurrence of Avian Infectious Bronchitis Virus in the Tissues of Experimentally Infected Chickens. Qld. J. Agric. and Anim. Sci. 24:75-80

• His wife Penny Stephens also worked at ARI and also published on IB – Stephens, P. and Simmons, G. C. (1968). Neutralising Antibodies for Avian Infectious Bronchitis Virus in Queensland Poultry Flocks. Aust. Vet. J. 44:29-30

Summary of Topics • History of Poultry Diseases in Australia (B. Bains), Newcastle Disease (P. Selleck), Avian Influenza (A. Turner), Marek’s Disease (C. Jackson), Infectious Laryngotracheitis (T. Bagust), Mycoplasmosis (K. Whithear), Pasteurellosis and Coryza (P. Blackall), Infectious Bronchitis (J. Ignjatovic), and Australian poultry industry unique points (C. Morrow) • Review papers on AI in Asia (C. Wilks), Campylobacter Control in NZ (D. Marks), food safety (J. Cox and D. Craig), Coles food policy (A. Currie), registration requirements (R. Pottie), minor food-producing species (A. Etherington) and Pigeon Paramyxovirus outbreak (S. Mccullough) • Research papers on ILT, IB and MG (Uni. Melb.), Pasteurella multocida typing (Monash Uni.), Necrotic Enteritis (CSIRO), enteric viruses (USDA Athens), S. Sofia (RMIT), E. coli (Uni. Melb., Pfizer and R. Jenner) and composting of poultry (DPI Vic.)

Infectious Laryngotracheitis (ILT) – Causes a Severe Respiratory Disease Photos courtesy of Rod Reece, NSW DPI

ILT Research Results – Uni. Melb. • Additional experimental data on a new candidate ILT vaccine, based on a glycoprotein G deficient strain, to be marketed by Bioproperties Aust. • Confirmation that eyedrop vaccination with Intervet (now MSD Animal Health) Serva strain results in a more rapid vaccinal viral replication than drinking water vaccination and that vaccine virus can be transmitted to in-contact susceptible chicks with Serva strain transmitting earlier than Pfizer SA2 strain following vaccination • Testing to show that Type 2 (Vic. 1999) and Type 4 (NSW 1970 CSW-1) ILT viruses were more similar to MSD Animal Health Serva strain vaccine (Type 7) than to Pfizer ILT vaccines (Type 1) which contain Australian ILT viruses. MSD Animal Health Serva vaccine was first used in Australia in late 2008.

Mycoplasma gallisepticum (MG) Causes Sinusitis, Air Sacculitis and Egg Production Drops

Research Results on Bioproperties ts-11 Mycoplasma gallisepticum (MG) Vaccine – Phil Markham, Uni. Melb. • Recent research (Microbiology 2011. 157:1740-1749) has shown that this cloned vaccine contains two types of bacterial cells, those with GapA expression and those without GapA expression (the majority) • GapA is the primary cytadherence molecule in MG and is thought to be necessary for prolonged colonization and survival of MG in the host • At a dose level 100 times less than the marketed ts-11 vaccine, GapA+ ts-11 experimental vaccine produced a higher percentage of RSAT serological positives than the marketed ts-11 vaccine, persisted longer in the trachea and protected similar to or better than the marketed ts-11 vaccine • Results may explain the variability in serological response following vaccination observed over the years • Results also may lead to a GapA+ ts-11 MG vaccine that is freezedried and can be administered by spray; the current ts-11 MG vaccine is frozen and must be administered by eyedrop

Infectious Bronchitis (IB) Causes Respiratory and Kidney Disease, Egg Production Drops and Egg Quality Abnormalities

Quasi-Species in Pfizer IB Vic S Vaccine – Kylie Hewson, Uni. Melb. • Kylie Hewson of the Uni. Melbourne discovered that this vaccine contains two sub-species (VicS-v and VicS-del) which differed molecularly • Pathogenicity testing revealed that the combination of the two viruses was more virulent than VicS-v alone • The VicS-v virus was of similar virulence to the other two Serotype B IB virus vaccines, namely Inghams Strain registered by Pfizer and Bioproperties and Steggles strain registered by MSD Animal Health • These results probably explain why VicS vaccine is not the favoured vaccine for day-old chicks because of sporadic vaccine reactions but is often used as a “booster” vaccine in egg layers and breeders

Colibacillosis Causes Mortality due to Fibrino-purulent Inflammation of Various Internal Organs

Escherichia coli Vaccines • Phil Lehrbach detailed a Pfizer live aroA gene deleted mutant strain 078 E. coli vaccine that is registered overseas • Marc Marenda of the Uni. Melbourne reported on initial research findings on a candidate live mutant E. coli vaccine lacking tonB and Fur genes • Kelly Tivendale of the Uni. Melbourne concluded from her research that human and Avian Pathogenic E. coli (APEC) that cause extra-intestinal E. coli infections are very similar; she recommended that protective gear such as masks and gowns should be worn when servicing poultry • Rod Jenner questioned the need to use E. coli vaccines in poultry, as E. coli is normally considered to be a secondary pathogen of which the harmful effects can be controlled by identifying and correcting the primary cause

Fowl Cholera (Pasteurella multocida Infection)

Pasteurella multocida Serotyping – John Boyce, Monash Uni. • Currently P. multocida is differentiated into 16 serovars by the Heddleston gel immunodiffusion test which is thought to recognise lipopolysaccaride (LPS) antigens which are specific to each type and are thought to be related to protection • Fowl Cholera vaccines are designed to protect against Heddleston serovars • However there is growing un-ease with the reliability and repeatability of the Heddleston scheme so Monash Uni. researchers are developing a Rapid Multiplex PCR assay to replace serotyping • However they have found that this PCR technology recognises 8 LPS genotypes in the 16 Heddleston serovars; additional chemical tests are being undertaken in Canada to try to clarify this finding • In addition, the Monash Uni. group are undertaking challenge studies to further investigate the correlation between serovar and immunovar

Salmonella enterica Serovar Sofia – Emily Gan, RMIT Melbourne • S. Sofia (a Group B salmonella) is the most common salmonella isolated from chicken meat in Australia but causes no known disease in poultry and there are very few reports of food poisoning in humans due to this serovar • Emily studied in vitro and molecular characteristics of S. Sofia and S. Typhimurium, another Group B salmonella which is a pathogen of both poultry and humans • Emily concluded that avirulence of S. Sofia was due to changes in a large number of virulence-associated genes • Hence it is unlikely that S. Sofia can become virulent, which is good news for the Australian chicken meat industry

Avian Paramyxovirus Type 1 Outbreak in Pigeons in Victoria – Sam Mccullough, CSIRO AAHL Geelong • Sam detailed some laboratory findings of the PPMV-1 virus that has been isolated from this outbreak in the Melbourne and Shepparton areas of Victoria which has killed 50-100% of infected pigeons • The origin of the virus has not been determined but molecularly it is similar to European PPMV-1 viruses • While the existing AAHL tests developed with the support of industry funding in past years were able to diagnose and classify the virus, additional tests have now been developed at AAHL to differentiate the virus from other ND viruses including Australian NDV • First passage virus did not result in clinical signs in chickens but a further four passages will be undertaken to determine if this PPMV-1 can adapt and cause disease in chickens • The finding of PPMV-1 in feral pigeons in seven cases in the Melbourne area is of concern to industry, but the current ND vaccination programs should protect broilers, egg layers and chicken breeders against this virus if it becomes virulent to chickens

Enteric Viruses – Michael Day, USDA Athens Georgia • Michael presented two talks on various viruses and bacteria that have been identified in cases of Poult Enteritis Complex (PEC), Poult Enteritis Mortality Syndrome (PEMS) and Runting-Stunting Syndrome (RSS) of chickens. • Metagenomic analysis using the Roche/454 Life Sciences technology has been used to identify and quantify various micro-organisms which includes some previously unknown viruses • The significance of most of these micro-organisms is unknown at this stage

Coles Egg and Chicken Meat Initiatives • Andrea Currie, a Food Technologist with Coles, presented a talk on “What Customers tell us – Eggs and Chicken Meat” • She stressed that the keyword is “trust” which is facilitated by auditable, creditable and transparent standards • Types of “product complaints” and who influences Coles policies were listed • “Value”, shorter shelf-life, cage-free eggs in home brand by 2013, stocking density of free-range egg layers, introduction of free-range turkey and higher welfare broiler products such as Bendigo Valley Chicken and Lilydale Free Range chicken and “free to roam” advertising for broilers received particular mention

Summary • As the 2-day meeting was recognising the 50th anniversary of the AVPA, there were a number of historical presentations on diseases by acknowledged experts in these diseases, which both the older and younger attendees seemed to value • The research papers in general reported very good research, mostly with definable outcomes. Presentation technique was deficient in some cases, partly due to the configuration of the meeting room • The Australian Poultry CRC, which has been in operation for about 10 years, has greatly expanded the poultry research output in Australia which previously depended mainly on funding from the Chicken Meat Committee of the Rural Industries and Research Corporation and the Australian Egg Corporation Limited, both of which continue to fund poultry research in Australia in addition to the Poultry CRC. • I have supplied an electronic copy of the proceedings to the secretary. Individual speakers may be willing to provide their presentations if requested personally

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