A simplified objective method for quantification of peste des petits ruminants virus or neutralizing antibody

A simplified and standardized assay based on haemagglutination of infected culture supernatants was developed to detect peste des petits ruminants (PP R) virus growth in vero cells and to quantify PPR neutralizing antibody. Vi rus titres estimated by visual reading of cytopathic effects as a criterion were compared with those estimated by haemagglutination of infected supern atants and no statistically significant differences were Seen between them. During quantification of PPR antibodies, the titres based on haemagglutina tion of supernatants on day 5 post-infection had a high sensitivity, specif icity and agreement in qualititative comparison with those determined by vi sual examination of cytopathic effects. In quantitative comparison, the cor relation coefficient between serum neutralization titres estimated by visua l examination of cytopathic effects or haemagglutination of supernatants wa s 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 h aemagglutination-inhibition titres also correlated well with serum neutrali zation titres with a coefficient of 0.78. Thus the haemagglutination-inhibi tion test appears to be a suitable alternative to the serum neutralization test for quantification of PPR neutralizing antibody. (C) 2000 Published by Elsevier Science B.V.