The use of PCR combined with restriction enzyme analysis to characterize fowl adenovirus field isolates from northern India.

Ten fowl adenoviruses (FAVs), isolated from suspected cases of inclusion body hepatitis (IBH) in quails and broilers, were characterized by a hexon-based polymerase chain reaction (PCR) combined with restriction enzyme analysis (REA) of the amplified DNA fragments. All the isolates could be detected using H1/H2 and H3/H4 primer sets. Amplification of DNA with H1/H2 and H3/H4 primer sets resulted in fragments of approximately 1219 bp and 1319 bp, respectively. HaeII digestion of the H1/ H2 PCR products and HpaII digestion of the H3/H4 PCR products characterized all the isolates in FAV groups, known from genomic typing using the whole DNA. For some of the isolates, neutralization tests were used to confirm these results. The results revealed that, as well as FAV serotype 1, which is the sole member of DNA group A, FAVs of DNA group E are also associated with IBH in poultry in northern India. The FAV specific PCR combined with REA was found to be very useful in investigating the epidemiological situation in the field. It was even possible to define mixed infections with more than one FAV.