Nucleotide sequence of L1 and part of P1 of hexon gene of fowl adenovirus associated with hydropericardium hepatitis syndrome differs with the corresponding region of other fowl adenoviruses.

In order to study the serotypic variations in hydropericardium hepatitis syndrome (HHS) causing virus, the DNA was extracted from the purified virus, a 0.7 kb variable region of hexon gene encoding L1 and part of P1 amplified and sequenced. Both nucleotide and derived amino acid sequences, corresponding to the variable region, were compared with the published fowl adenovirus sequences (FAV serotypes 10, 1 and 8). As expected the 0.7 kb sequence showed single open reading frame (ORF). There was a nucleotide sequence variation of 8.2, 28.1 and 40.3%, respectively, with FAV serotypes 10, 1 and 8. The dendrogram constructed with the nucleotide sequences showed that HHS virus and FAV10 are closer to each other and are away to FAV1 and FAV8. However, the derived amino acid sequence showed variations as high as 28.8, 38 and 45.1% with FAV serotypes 10, 1 and 8, respectively. Such high degree variation has been found due to the shift in the reading frame caused by deletions indicating that the FAV4 associated with HHS is unique and different from FAV10. To the best of our knowledge this is the first report on nucleotide sequence analysis of hexon gene fragment of FAV4 associated with HHS.