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Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Red blood cell elution time of strains of Newcastle disease virus | J. Vet. Set. 2005 6 4 287-288 JOURNAL OF Veterinary Science Red blood cell elution time of strains of Newcastle disease virus M. c. o. Ezeibe E. T. Ndip Department of Veterinary Medicine University of Nigeria Nsukka Nigeria 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. Key words elution time HA test NDV Introduction Newcastle disease virus belongs to the íàmily Paramyxoviridae 5 and the serotype paramyzovirus 6 . The disease produced often varies widely depending on the strain of the virus in affected chickens. So in diagnosis it may be necessary to identify the strain of the virus involved in each outbreak. Some biological activities of the Newcastle disease virus are characteristic of the different strains. These include hemagglutination of specific erythrocytes 2 neuraminidase activity cell fusion and hemolysis 7 . Neuraminidase mucopolysaccharide N-acetyl neuraminyl hydrolase E. 3.2 1 18 is a component of the hemagglutinin-neuraminidase antigen. The neuraminidase is responsible for clipping off of the bond between red blood cell receptors and the viral hemagglutinins elution observed in hemagglutination of red .
