DETECTION OF AVIAN INFECTIOUS BRONCHITIS VIRUS AND VIRUS-SPECIFIC ANTIBODY IN DIFFERENT AGES OF LAYER BIRDS OF SMALL SCALE COMMERCIAL FARMS

Abstract

The present study was carried out to detect infectious bronchitis virus (IBV) by clinical observation, propagation of virus and serological test. The clinical manifestations of the affected flocks were found Sneezing, coughing, respiratory distress, depression, egg production drop suddenly, low egg quality. Caseous materials were present and blocked the nasal passage. On post mortem Trachea, lungs, ovary and oviduct were collected aseptically and inoculums was prepared. A total of 0.2ml of the 10% Trachea or lungs or ovary and oviduct suspension was inoculated on the AS route of 10 days old embryonated indigenous chicken eggs. Mortality of the one or two embryo was observed as early as 48 hours post infection.While mortality of the other embryos occurred between days 2 to 7 of inoculation. The dead infected embryo showed dwarfing, curling and pathognomic sign of IBV. The sera sample collected from seven age group layer bird of different small scale layer farm in Dinajpur district of Bangladesh. Indirect ELISA (IELISA) was performed to detect the IBV specific antibody. The highest antibody titre was recorded as 14849 and lowest antibody titre was recorded as 204. The total 70% sera samples were showed positive result. The highest mean titre was found in group A6 as 9206.53 which are 63-73 ages’ birds determined by a commercial ELISA kit (Biocheck, UK). Among the seven age group of different small scale layer farm 63-73 weeks age’s layer birds of Lotifur Layer Farm, Ramdubi, Dinajpur showed higher prevalence rate and suffering from IBV.