Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/1999
Publication Date: N/A
Citation: Interpretive Summary: Hemorrhagic enteritis of turkeys is a serious problem for the poultry industry. The causative gent is an adenovirus, hemorrhagic enteritis virus (HEV). Although there is a commercial HEV vaccine that protects against HEV, the vaccine tends to be immunosuppressive (lowering the ability of a bird to respond to foreign bacteria and viruses) and interferes with the turkey's ability to mount a good immune response to other vaccines or opportunistic infections. We made a recombinant virus by expressing the HEV hexon protein (a protein that is normally part of the protein coat of HEV) in a vaccine strain of fowlpox virus. Turkeys inoculated with the recombinant virus were protected against a HEV challenge. No immunosuppression was observed. Thus, the recombinant fowlpox virus may be a better HV vaccine than the commercial HEV vaccine.
Technical Abstract: Hemorrhagic enteritis (HE) is an economically important disease of turkeys. It is caused by a type II aviadenovirus, hemmorrhagic enteritis virus (HEV). The vaccines currently available to the commercial poultry producer are highly effective in preventing disease outbreaks, however, they are immunosuppressive. A recombinant fowlpox virus (rFPV) expressing the native hexon of HEV has been shown to induce an anti-HEV humoral immune response in turkeys (Cardona et al., in preparation). In this study, a rFPV expressing the native hexon of HEV was compared to a commercial HEV vaccine (vxHEV) for its ability to protect turkeys from virulent HEV challenge. Complete protection from the intestinal lesions of HE was achieved in experimental groups vaccinated with either the rFPV or the vxHEX. Lymphocyte stimulation was measured in turkeys inoculated with rFPV, vxHEV, a sublethal dose of HEV, or not inoculated. Immunodepression in turkeys given the rFPV was not significantly different from the variation observed in uninoculated turkeys.