Isolation and molecular confirmation of avipoxvirus in backyard chicken in West Bengal

The present study describes the isolation, PCR and nucleotide sequencing based confirmation of Avipoxvirus in backyard flocks of two different agro climatic zones in West Bengal. The scabs of beak, comb, wattle and tissues were collected from eight infected birds reared under backyard management system in two villages situated in two different agro-climatic zones in West Bengal {South- 24 Parganas district (coastal) and Jalpaiguri district (terai)} in April 2011 for laboratory examination. The processed tissues were inoculated into the chorio allantoic membrane (CAM) of 11 days old specific pathogen free embryonated hen's eggs. The viral DNA was extracted from the collected scabs and subjected to Avipoxvirus specific PCR by amplification of 4b gene. The nucleotide sequencing of the PCR products was carried out and the sequence homology searches were conducted using the BLAST algorithm. In the CAM of the inoculated eggs gross pock lesion with severe thickening was observed after 7 days incubation in two samples collected from two different agroclimatic zones. The Avipoxvirus specific PCR also generated the expected 578 bp amplicon from both the samples. The nucleotide sequence of these PCR products was found to be cognate (99% similarity) with the 4b gene of several other fowl pox virus isolates as found in NCBI genebank.