Abstract
Avian influenza virus (AIV: H-5) infections arc persisting in wild birds in sub-clinical form and are source of dissemination to commercial birds. In an outbreak, rapid detection of the AIV is considered to be a valuable tool for its handling on poultry farms. In the present study, 975 samples of tissue homogenate, tracheal, and cloacal swabs (325 of each) were collected from 40 suspected flocks (10 layer breeder and 30 commercial layers) and were processed for AIV detection using reverse transcriptase polymerase chain reaction (RT-PCR), and virus culture and identification techniques. The AIV was detected from 92 (9.4%) samples (12 samples of tissue homogenate, 50 tracheal and 30 cloacal swabs) of 4 (10%) layer flocks (one layer breeder and 3 commercial layer) using RT-PCR technique while the virus was confirmed from 16 (1.6%) samples (10 samples of tissue homogenate, 20 tracheal swabs and 10 cloacal swabs) of 2 (5%) flocks (one layer flock of each category) using virus culture technique. Fifty tracheal swabs (15.4%), 30 cloacal swabs (9.2%) and 12 tissue homogenate (3.7%) showed presence of the AIV through RT-PCR and 20 tracheal swabs (6.2%), 10 cloacal swabs (3.1%) and 10 Tissue homogenate (3.1%) showed presence of the virus through the virus culture technique. In conclusion, AIV subtype 145 was prevailing in poultry layer flocks in and around Faisalabad city, Pakistan. Tracheal swabs were the most reliable source of sample for detection of virus RNA using RT-PCR technique and isolation of the virus for subsequent confirmation through hemagglutination inhibition (HI) test.