Polymerase chain reaction based differentiation of various fowl adenovirus serotypes causing inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) of poultry in India

The study describes a simple, reliable and quick method to molecularly identify and differentiate the various serotypes of fowl adenoviruses incriminated with the causation of inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) in poultry flocks of the country. The hypervariable region of hexon gene was amplified by PCR and subsequently the amplicons were subjected to RE analysis, with a set of six restriction endonucleases viz. Alu I, Bam H I, Hha I, Hpa II, Rsa I and Sma I. PCR could amplify 0.7 kb fragments from the DNA of all the eight FAV isolates/strains used in the study and RE analysis of the PCR products with restriction endonucleases viz. Alu I, Hha I, Hpa II, Rsa I and Sma I revealed that all the eight FAV isolates/strains broadly gave two types of RE profiles with each enzyme. Bam H I did not digest any of the amplicons. The RE profile of FAV-12 was distinct from that of FAV-4 strains, with each of the enzyme. Isolate 421/AD/98 (a mixture of FAV-4 and FAV-12 isolated from natural case of IBH-HPS), gave a mixture of bands from both of the above-mentioned patterns, with each of the enzyme. This technique can conveniently be used to identify the serotype of fowl adenovirus/viruses involved in the causation of IBH-HPS, before a vaccination or control strategy is applied, in the event of an outbreak.