獣医科学と技術

A Comparative Study of New Castle Disease Virus Isolated From Poultry with Standard Velogenic Strain

Abstract

Karmakar DB, Majee SB, Karikkathil SS, Seth D, Mondal S

Newcastle disease [avian paramyxovirus serotype 1 (APMV-1)] is highly prevalent in poultry thought India. The present study was undertaken to extrapolate the pathogenecity of a field isolate of Newcastle disease virus (NDV) in comparison with velogenic BOM-1 isolate (AY 294125). The field NDV isolate and the BOM-1 isolate were propagated in SPF eggs and the infected allantoic fluids were used for characterization of pathotype. The Mean Death Time (46 hours), Intracerebral Pathogenicity Index (1.74), Intravenous pathogenicity Index (2.01) were enumerated to find out the pathotype of the virus. The field NDV isolate was able to agglutinate mammalian erythroytes except equine RBCs, stable at 56°C for 60 mins and proved to be a rapid eluter. It formed plaques (5.39 x 106 PFU/ ml) in chick embryo fibroblast with characteristic cytopathic effects of velogenic NDV comparable with BOM-1 isolate. The viral proteins that were detected by SDS-PAGE were HN (76 KD), F (66 KD), NP (55 KD) and M (44 KD). The total protein in the field virus isolate was determined to be 18.75 mg%, which was lower than that of the total proteins in BOM-1 isolate (45 mg%). The field virus contained 28.83 mg% of total lipids and 4.98 mg% total carbohydrates, which were more or less similar to that of BOM-1 isolate and that of allantoic fluid. On the basis of all the biological and the chemical tests conducted, the field virus isolate included in this present study was characterized as velogenic viscerotropic strain of NDV.