Studies on the association of hydropericardium syndrome with infectious bursal disease under field conditions

This study aimed to detect and differentiate fowl adenovirus field isolates associated with hydropericardium syndrome (HPS) and its association with infectious bursal disease. Fourteen liver samples from suspected outbreaks of HPS when subjected to AGPT, dot-ELISA and PCR revealed virus antigen in six, eight and eleven samples, respectively. Histopathologically, nine out of fourteen samples showed the presence of intranuclear inclusion bodies. Eleven samples showed characteristics cytopathic effects (CPE) when passaged in chicken embryo liver cell culture. PCR when applied using the primer H1/H2 and H3/H4 amplified 1219 base pair and 1319 base pair products respectively, indicating the presence of fowl adenovirus. Restriction enzyme analysis of 1219 and 1319 base pair products of eleven isolates with Hae II and Hpa II, respectively, generated a pattern, which resembled to the restriction pattern of FAV-4. Characteristics IBD virus genome of 474 base pair could be detected from the four out of fourteen bursal inoculums by RT-PCR. However, association of HPS with IBD could not be detected either clinically or histopathologically even though in two cases IBD virus could be detected concurrently with FAV-4. IBD virus being detected could be the vaccine virus as these samples came from birds having history of IBD vaccination. These results revealed that FAV-4 was associated with field out breaks of HPS and PCR can be used effectively for the detection offowl adenovirus.