Red blood cell elution time of strains of Newcastle disease virus.

Elution time of velogenic, mesogenic and lentogenic strains of Newcastle disease virus was determined. The differences in their elution time were also calculated. Four samples, each of a velogenic strain (VGF2), a mesogenic strain (Komarov) and a lentogenic strain (LaSota) were used for hemagglutination test with 0.6% chicken red blood cells. The time it took for wells of the end hemagglutination points (highest dilution that gave agglutination) to elute was recorded as elution time for each sample. The mean elution time of the three strains of Newcastle disease virus differed significantly (p < 0.05). The velogenic strain gave the highest mean elution time of 118 min, followed by the mesogenic strain with 59 min and the lentogenic strain with 25 min. Based on this result it appears that elution time could form a basis for rough characterization of isolates of Newcastle disease virus into the three major strains.