Screening of diseases in wild exotic birds on Tahiti Island – implications for French Polynesian conservation

Abstract

In order to identify potential infectious disease threats to the native avifauna of French Polynesia, an evaluation was performed on the health status of four wild non-native species of birds on the island of Tahiti: common myna, red-vented bulbul, rock dove, and zebra dove. From six locations, a large sample set (151–349 individuals) was tested for several viruses and bacteria, and a small sample set (22–40 birds), because of its proximity to the last remaining population of the critically endangered Tahiti monarch, was checked for more pathogens. Disease-specific screening methods were used. None of the following viruses were found: Newcastle disease virus, avian influenza virus, West Nile virus in 159, 189 and 204 sera; 349 birds examined for poxvirus lesion; avian metapneumovirus and avian adenovirus in 38 and 38 sera; avian polyomavirus in 28 cloacal swabs. The prevalence of bacteria and avian malaria was: Salmonella Heidelberg (5% from 21×10 pooled samples of intestinal contents), Chlamydia spp. (8% on 196 cloacal swabs) including Chlamydia psittaci (3%), Plasmodium relictum – haplotype GRW04 (2% on 205 DNA), Haemoproteus spp. (25% on 205 DNA). In the limited sample set, Klebsiella pneumoniae, Bordetella avium and Riemerella columbina were isolated with a prevalence of 3% each in 40 tracheal swabs. The potential role of introduced birds as vectors of zoonosis in French Polynesia and the crucial finding of Plasmodium relictum with several ubiquitous and dangerous pathogens on Tahiti Island should be given the appropriate attention by local authorities and conservationists.