Development of sandwich elisa for the detection of fowl adenovirus 4 associated with hydropericardium syndrome in experimentally infected chicken.

A sandwich ELISA was standardized to detect fowl adenovirus (FAV) group I antigen in various tissues, namely liver, spleen, bursa, thymus and kidneys of chicks experimentally infected with fowl adenovirus 4 (FAV-4) isolated from cases of inclusion body hepatitis-hydropericardium syndrome (IBH-HPS). The assay was found to be more sensitive and more specific in comparison to an agar gel immunodiffusion (AGID) test, as it could detect FAV antigen below the titer of 20,000 TCID50/ml and below 1.14 microg in 5% (w/v) suspensions of liver tissue. In 2-week-old experimentally infected chicks, the antigens were detectable by ELISA in liver from 3 to 15 days, in thymus from 3 to 7 days, and in kidneys, bursa and spleen from 3 to 10 days post infection (p.i.). Maximum antigen concentration in terms of ELISA absorbance values was detected in liver and kidneys, which could be used as tissues of choice for virus isolation or detection of viral antigens from IBH-HPS cases.