An enzyme-linked immunosorbent assay for detection of hemorrhagic enteritis virus and associated antibodies

An enzyme-linked immunosorbent assay (ELISA) that detects antibodies specific for type II avian adenoviruses is described. Freon-treated extracts from spleens of hemorrhagic enteritis (HEV)-infected poults were a better source of antigen than the cell-culture-propagated virus. Antigen-coated microtiter wells treated with bovine serum albumin reduced nonspecific adsorption of immunoglobulins. The ELISA readily detected antibodies in hemorrhagic-enteritis- and marble-spleen-disease-infected field flocks of turkeys and pheasants. Antibody was also detected 1 week after vaccination of 2-week-old poults with cell-culture-prepared hemorrhagic enteritis vaccine. The assay was specific and more sensitive than agar-gel-precipitation and virus-neutralization tests. HEV-related antigens in infected spleens were also detected indirectly in a blocking ELISA by removal of HEV antibodies (Ab) from stock (Ab+) serum through antigen-antibody complex formation. Extracts from HEV-infected poults reduced specific antibody reactivities in HEV-antigen-coated wells, whereas extracts from HEV-challenged poults previously vaccinated with attenuated virus did not remove HEV antibodies.