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Biomedical subjects

J T Faragher

Publications and source records attributed to J T Faragher.

13 recordsLinked to original sources
PubMed1990

Isolation of very virulent Marek's disease viruses from vaccinated chickens in Australia.

Very virulent Marek's disease viruses (vvMDV), defined as isolates against which the herpesvirus of turkey (HVT) vaccine provide poor protection, have been isolated from poultry flocks in both the United States and Europe. Twenty-one samples from vaccinated Australian flocks, experiencing problems with excessive Marek's disease (MD), were tested for the presence of transmissible MD viruses (MDV). Of the 16 samples which contained a transmissible agent, 14 were pathogenic in chickens, based on the development of MD lesions or depression of the bursa/body weight ratio. Of the pathogenic isolates which have been successfully typed 10 were serotype 1, and one was serotype 2 MDV. Pathogenicity of isolates varied. Several isolates caused tumours in 20-30% of both vaccinated and unvaccinated chickens. Two isolates, MPF6 and MPF23, caused tumours in more than 50% of chickens. When MPF6 and MPF23 were tested in vaccine trials bivalent vaccine gave no better protection against development of MD lesions than a monovalent vaccine. Isolate MPF23 was so pathogenic that lesions were produced in all chickens, regardless of the vaccine protocol used. Therefore vvMDV have been isolated in Australia, and unlike the vaccines tested overseas, bivalent Australian vaccines do not appear to provide greater protection against these vvMDV.

Animals↗
PubMed1989

Avian infectious bronchitis: cross-protection studies using different Australian subtypes.

The cross-immunity of vaccinated chickens after challenge with some Australian infectious bronchitis viruses was assessed by humoral antibody responses and by ciliary activity in tracheal rings of vaccinated chickens following challenge. Four viruses were used for vaccination: Vac 3, Vac 4, both current infectious bronchitis vaccine viruses, and Q1/76 and N2/62. IBV N1/62 (synonym T0 and infectious bronchitis virus N9/74 (synonym Appin) were used to challenge the vaccinated chickens. Results showed a lack of correlation between humoral antibody levels and protection. Cross-immunity was found after vaccination with each subtype, but was lower for Vac 3 and Vac 4 than for Q1/76 and N2/62.

Animals↗
PubMed1981

Australian infectious bronchitis viruses: identification of nine subtypes by a neutralisation test.

The antigenic relationships between 17 Australian infectious bronchitis viruses, including six vaccine viruses, were studied by a neutralisation test using a plaque reduction method in chick embryo kidney cell monolayers. The 17 viruses formed nine distinct subtypes. Antiserum to each subtype had a high titre to viruses of the same subtype and a lower titre to viruses of different subtypes. The heterologous titres of sera varied widely.

Antigens, Viral↗
PubMed1975

A comparison of commercial Mycoplasma gallisepticum antigens in the rapid serum agglutination test.

Twenty-three chickens, aged 9 weeks, were housed in contact with a similar group of chickens which were infected with M. gallisepticum. The onset and development of the serum agglutinin responses which were detected by 3 commercial antigens using rapid serum agglutination tests up to 20 weeks of age, differed greatly both between the infected and in-contact groups and, within the latter group, between the antigens. Few reactions, which were weak and transient, were detected in 2 similar groups of chickens, neither infected with M. gallisepticum but 1 vaccinated at 12 and 17 weeks of age with killed Pasteurella multocida oil adjuvant vaccine.

Agglutination Tests↗