Exposure of Threatened Accipitridae to Mycobacterium bovis Calls for Active Surveillance

Abstract

Anthropogenic activities have cumulatively led to the dramatic decline of world populations of vultures that currently face serious survival challenges in several regions of the world. In Portugal, the three resident species qualify as endangered and are under conservation efforts, mainly in the central east and south-east regions, where habitat protection and artificial feeding stations were implemented. Concurrently, the areas under protection are highly affected by tuberculosis (TB) in cattle and wild ungulates, whose potentially infected carcasses may naturally or artificially be used as feed by local vultures. In this work, we opportunistically surveyed populations of Eurasian griffon (Gyps fulvus) and Eurasian black vulture (Aegypius monachus) for the presence of Mycobacterium bovis. Nine pathogenic mycobacteria, including one M. bovis isolate, were cultured from the oropharynx of nine of the surveyed vultures (n = 55), sampled in recovery centres or in artificial feeding stations. Genotyping of the M. bovis strain indicated spoligotype SB0121, the most frequent type in Portugal, and a unique MIRU-VNTR profile that differed in two loci from the profiles of SB0121 bovine and deer strains from the same geographical area. The M. bovis-positive griffon exhibited poor clinical condition when admitted to the recovery centre; however, clinical evidence of TB was not present. Although the significance of M. bovis isolation in this vulture specimen could not be ascertained and despite the accepted notion that vultures are naturally resistant to microbial pathogens, the sanitary follow-up of Accipitridae vulture populations in TB-hotspot areas is essential to safeguard ongoing conservation efforts and also to evaluate the suitability of standing legislation on deliberate supplementary feeding schemes for menaced birds of prey.

Implications of bacterial, viral and mycotic microorganisms in vultures for wildlife conservation, ecosystem services and public health

“…2018) and even some Mycobacterium species (Cunha et al . 2017). Vultures can also be exposed to host‐specific human pathogens.…”

Avian tuberculosis in a free-living Eurasian griffon vulture

“…The highly corrosive environment in the digestive tract of vultures destroys most pathogenic microorganisms. 5 Nevertheless, ATB can affect vultures and other raptor species, 5,16 perhaps because of immunosuppression, immunodeficiency, exhaustion, or the existence of other infectious diseases and intoxications.…”

Molecular evidence for Mycobacterium bovis infection in wild Chilean hawk (Accipiter chilensis)

“…Diseases of birds of prey kept in captivity as well as free-living raptors are well documented (Millán et al 2010, Vidal et al 2017. Serological studies show that free-living birds are exposed to pathogens through contact with poultry waste and run-off from farms, or by ingestion of contaminated carcasses (Höfle et al 2002, Cunha et al 2017, first being susceptible hosts, thereafter potential sources of the infection. The aim of the present study was to provide evidence of M. bovis infection in a wild Chilean hawk specimen found dead in southern Chile, where the major part of the Chilean livestock production system is situated.…”