Usefulness of Polymerase Chain Reaction in Early Detection and Tissue Tropism of Fowl Adenovirus in Experimentally Infected Chicken

Veterinary Research Communications -     

Methanol-precipitated, detergent-treated newcastle disease virus as an agar-gel precipitation test antigen

Summary Methanol-precipitated, detergent-treated (Triton X-100) Newcastle disease virus (NDV) was found suitable as an agar gel precipitation test (AGPT) antigen. One hundred and twenty sera were tested by the haemagglutination-inhibition (HI) test and AGPT against NDV. There was a very significant increase in the proportion of AGPT positive samples with increase in HI titre. Hence AGPT can be recommended as a field based test for seromonitoring following vaccinations against ND where laboratory facilities are inadequate.

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Utilizacion De Virus De La Enfermedad De Newcastle Precipitado Con Metanol Y Tratado Con Detergente Como Antigeno En Un Test De Precipitacion En Agar Gel

Resumen Virus de la enfermedad de Newcastle (NDV) precipitados con metanol y tratados con detergente (Triton X-100) resultaron ser adecuados como antígenos para un test de precipitación en agar gel (AGPT). Se realizaron AGPT y tests de inhibición de la hemoaglutinación en 120 muestras de suero. Se encontró un aumento muy significativo en la proporción de muestra positivas según AGPT conforme aumentaba el título de anticuerpos determinado según HI. Por tanto, cuando las instalaciones de laboratorio no son adecuadas, AGPT puede ser recomendado como test de campo para seromonitorización después de vacunar frente a la enfermedad de Newcastle.

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Utilisation D’un Virus De La Maladie De Newcastle Traite Par Detergent Et Precipite Au Methanol Pour La Preparation D’un Antigene Dans Un Test De Precipitation Sur Agarose

Résumé Un virus de la maladie de Newcastle, traité par un détergent (Triton X-100 et précipité au méthanol fut reconnu utilisable comme antigène pour un test de précipitation sur agarose (AGPT). 120 serums furent testés par test d’inhibition hemo-agglutinant et par AGPT contre le virus de la maladie de Newcastle. Il y eut une augmentation significante dans la proportion d’échantillons positifs par AGPT avec l’augmentation du titre Hi. Désormais l’AGPT peut être recommandé comme un test de terrain pour le serodiagnostic après vaccination contre la maladie de Newcastle lorsque les facilités de laboratoire ne sont pas adéquates.

     

Evaluation of a Filter Paper Blood Sampling Technique for Quantitative Assessment of Antibodies to Infectious Bursal Disease Virus

Tropical Animal Health and Production -     

Development of monoclonal antibodies against VP28 of WSSV and its application to detect WSSV using immunocomb

White spot disease (WSD) is an important viral disease of penaeid shrimp caused by white spot syndrome virus (WSSV). WSSV isolated from WSD outbreaks in commercial shrimp (Penaeus monodon) farms in India were propagated in the laboratory in healthy shrimp. The virus was purified from the infected tissues by sucrose gradient centrifugation. The VP28 was electroeluted from SDS-PAGE gels and was used to immunize Balb/c mice to produce hybridomas secreting monoclonal antibodies (MAb) against WSSV. A total of five hybridoma clones secreting MAbs to VP28 were produced. The MAbs were of the isotypes IgG1, IgG2b and IgM. The MAbs reacted with VP28 of WSSV and not with any other viral or shrimp protein in western blot. The MAbs were used to develop dot immunoblot assay using an immunocomb to detect WSSV from field samples. The test developed had an analytical sensitivity of 625 pg and a diagnostic sensitivity of 100% compared to single step polymerase chain reaction (PCR). The test can be used as an alternate for first step PCR to detect WSSV from field samples.     

Rapid Serological Profiling by an Immunocomb-based Dot-enzyme-linked Immunosorbent Test for Three Major Poultry Diseases

An immunocomb-based dot-ELISA, employing specially designed apparatus, was used to measure the antibody status for the three major poultry diseases--Newcastle disease, infectious bursal disease and infectious bronchitis--in single test sera. Positive samples could be classified into strong, moderate and weak positives by comparison with the colour reaction given by known strong and weak positive serum controls. The simultaneous dot-immunobinding assay gave reproducible results and allowed considerable savings on the cost of reagents compared to liquid ELISA. The antigen-coated immunocomb can be stored under refrigeration and the test can be performed rapidly under field conditions by trained personnel.     

Comparison of Newcastle disease vaccines by serology using serum,tears and feather pulp samples

Seroconversion of 3 lentogenic commercial Newcastle disease (ND) vaccines and experimental V₄ vaccines was compared based on the haemagglutination inhibition (HI) test against ND. It was found that for primary vaccination all the vaccines produced similar response but for secondary vaccinations V₄ and LaSota were better than RDVF. Eighty-five samples each of serum, tears and feather pulp were collected from respective birds and antibody assessment was done against ND by HI test. The geometric mean HI titres (GMT) of serum samples were highest followed by tears and feather pulp samples before vaccination and 3 weeks after vaccination by oculonasal route and the difference was statistically significant (p<0.01). Three weeks after booster vaccination by oculonasal route, however, the GMT of serum samples were highest followed by feather pulp and tears samples. The ease of collection of feather pulp samples and their role in ND serology is discussed.