ISOLATION AND CHARACTERIZATION OF INFECTIOUS LARYNGOTRACHEITIS VIRUS IN LAYER CHICKENS

Abstract

The present research work was conducted for the isolation and characterization of infectious laryngotracheitis (ILT) virus in layer chickens from commercial farms of Gazipur District. A total of 25 field samples were collected from suspected layer chickens of five commercial farms and were cultivated into 10-12 days old embryonated chicken eggs through chorioallantoic membrane (CAM) route for isolation of field virus. The field viruses were characterized by physico-chemical properties against pH, heat, ether and chloroform, serological test such as virus neutralization test (VNT) and passive haemagglutination (PHA) test and pathogenicity testing. In the embryonated chicken eggs, virus produced discrete pock lesions as early as 2 days of post inoculation and embryo death was recorded within 4-6 days of inoculation. The viruses could be inactivated by pH 4 within 2 hours. Inactivation of viruses was observed at 600C for 6 minutes, 550C for 15 minutes and 380C for 2 days. Ether-chloroform treatment also inactivated the viruses. Virus neutralization test revealed that all the virus isolates were neutralized by antiserum to ILT vaccine. Passive haemagglutination test showed that the tanned sheep RBC sensitized with the virus isolates were agglutinated in presence of the antiserum to ILT vaccine. The pathogenicity test recorded 100% mortality in experimental chickens. Data of this study suggest that the field isolates might be infectious laryngotracheitis virus.DOI = http://dx.doi.org/10.3329/bjvm.v8i2.11194 Bangl. J. Vet. Med. (2010). 8 (2) : 123-130