Factors affecting hemagglutination activity of avian influenza virus subtype H5N1

Hemagglutination [HA] and hemagglutination inhibition [HI] tests for avian influenza [AI] virus [H5N1] were standardized using varying various factors like erythrocytes from different species, type of diluent, incubation temperature and incubation period. The virus was peropagated in embryonated chicken eggs [9-11 days]. The allantoic fluid [AF] was harvested 36 hours post incubation and was confirmed by slide hemagglutination test. The maximum HA titres were obtained using 1% RBCs of chicken, sheep, duck, geese, pigeon, quails and turkey for 30-40 minutes. The haemagglutination activity showed best titer when used phosphate buffer saline than normal saline and also when incubated at 25[degree sign] C instead of 37[degree sign] C