RESUMO
A simplified and standardized assay based on haemagglutination of infected culture supernatants was developed to detect peste des petits ruminants (PPR) virus growth in vero cells and to quantify PPR neutralizing antibody. Virus titres estimated by visual reading of cytopathic effects as a criterion were compared with those estimated by haemagglutination of infected supernatants and no statistically significant differences were seen between them. During quantification of PPR antibodies, the titres based on haemagglutination of supernatants on day 5 post-infection had a high sensitivity, specificity and agreement in qualititative comparison with those determined by visual examination of cytopathic effects. In quantitative comparison, the correlation coefficient between serum neutralization titres estimated by visual examination of cytopathic effects or haemagglutination of supernatants was 0.96, when haemagglutination was done on day 5 post-infection. The virus and serum neutralization titres can thus be estimated objectively using the haemagglutination of supernatants as criterion to measure endpoints. The haemagglutination-inhibition titres also correlated well with serum neutralization titres with a coefficient of 0.78. Thus the haemagglutination-inhibition test appears to be a suitable alternative to the serum neutralization test for quantification of PPR neutralizing antibody.
Assuntos
Anticorpos Antivirais/sangue , Vírus da Peste dos Pequenos Ruminantes/crescimento & desenvolvimento , Replicação Viral , Animais , Galinhas , Chlorocebus aethiops , Efeito Citopatogênico Viral , Testes de Hemaglutinação/métodos , Testes de Neutralização , Vírus da Peste dos Pequenos Ruminantes/imunologia , Vírus da Peste dos Pequenos Ruminantes/isolamento & purificação , Sensibilidade e Especificidade , Células VeroRESUMO
Rabies occurs in all parts of Indian sub-continent except Andaman and Nicobar and Lakshadweep group of islands. The full-length nucleoprotein (N) gene sequence of a rabies virus isolate from India is reported for the first time and the same has been compared with available N gene sequences from the database. A central domain of 230 amino acids (aa) from aa 141 to aa 370 exhibited more than 95% similarity. There were 8 amino acid positions (aa 29, 32, 38, 84, 119, 379, 438, and 439) at which substitution was unique for Indian isolates but common for laboratory strains. In antigenic epitopes, except for a single amino acid difference at the antigenic site IV, the amino acids were conserved. The Indian isolate also possessed two Bam HI sites (aa 247 and 278), while the other Asian isolates had only one site at aa 278 or were not digested with Bam HI at all. Phylogenetic analysis also demonstrated that the Indian isolate was closely related to the Sri Lankan isolate and grouped in the cluster that comprised of the isolates from other Asian countries namely China and Pakistan.
Assuntos
Nucleocapsídeo/genética , Nucleoproteínas/genética , Vírus da Raiva/genética , Animais , Cães , Índia , Dados de Sequência Molecular , Proteínas do Nucleocapsídeo , Filogenia , Raiva/veterinária , Raiva/virologia , Vírus da Raiva/classificação , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
This report describes the isolation and molecular characterization of Newcastle disease virus isolated from an apparently normal guinea fowl (Numida melagridis). With a mean death time of 54 h and intracerebral pathogenicity index of 1.80, the isolate has been identified as velogenic by biological methods. Fusion protein cleavage site amino acid sequence analysis of the isolate indicated the presence of two pairs of basic amino acids at the C-terminus of the F2 region and phenylalanine at the N-terminus of the F1 region, confirming the velogenic nature of the isolate. Phylogenetic analysis of the isolate revealed that this isolate is genotypically related to other neurotropic velogenic isolates like Iowa/Salsbury, Texas GB, Kansas/Manhattan and mesogenic Michigan.