Humoral response to H5N2 vaccination in exotic birds in the United Arab Emirates.
A prophylactic vaccination programme was established after considering the risk of an outbreak of highly pathogenic avian influenza in exotic birds kept in open exhibits in 2 zoological collections in Dubai (Sheikh Butti Wildlife Centre and Wadi Al Safa Wildlife Centre). 122 birds (12 Anseriformes, 8 Ciconiiformes, 13 Charadriiformes, 39 Galliformes and 50 Gruiformes) were inoculated with a combination of 2 commercially available oil emulsion inactivated vaccines. Five unvaccinated houbara bustards (Chlamydotis undulata macqueenii) were used as controls. In general, antibodies were detected in all the species 8 weeks after the vaccination. The control birds remained seronegative throughout the study. 100% seroconversion was achieved in the thick-knees (Burhinus capensis), crowned cranes (Balearica pavonina), Carolina ducks (Aix sponsa), fulvous tree ducks (Dendrocygna bicolor) and wild turkeys (Meleagris gallopavo) after a single dose of the vaccine. A second dose of the vaccine was needed to obtain 100% seroconversion in the silver pheasants (Lophura nycthemera) and white-bellied bustards (Eupodotis senegalensis). Some houbara bustards, crested guineafowl (Guttera pucherani), greater flamingos (Phoenicopterus ruber) and stone curlews (Burhinus oedicnemus) remained seronegative even after 8 weeks and 2 doses of vaccine. The species with the highest mean antibody titre at 8 weeks post-vaccination were silver pheasants (7.8), wild turkeys (7.5), white-bellied bustards (6.5), houbara bustards (5.8), Carolina ducks (5.7) and greater flamingos (5.7). The immunized birds did not show any adverse reactions related to the vaccine. Moreover, no mortality related to the vaccination was reported. It was concluded that the inactivated H5N2 vaccine was immunogenic for a variety of exotic avian species.