Faecal bacteria associated with different diets of wintering red kites: influence of livestock carcass dumps in microflora alteration and pathogen acquisition.
Abstract
Despite the important role of refuse dumps for the conservation of threatened avian scavengers, there is no information about the direct effects on scavenger health from feeding on meat remains found at these places, including the potential for exposure to infections agents and harmful chemical residues. We assessed the composition, species richness and prevalence of faecal microflora of wintering red kites Milvus milvus in two areas of central Spain where kites fed primarily on carrion from stabled livestock reared in intensive conditions (Segovia) versus those that fed on wild rabbits Oryctolagus cuniculus (Madrid). Faecal bacterial flora composition, species richness and prevalence differed between areas. These differences were attributed to diet and the environmental conditions found at the sites where the kites obtained most of their food. The intestinal microflora of kites feeding on carrion from stabled livestock (mostly fattening pigs) differed from the flora considered to be normal for a healthy raptor. Salmonella sp. was found in a relatively high proportion of samples from Segovia (25%), 6% of those samples yielded in pure culture (serotypes enteritidis and gallinarum). If these serotypes cause disease in kites and other raptors, as they do for poultry and some other birds, there may be cause for concern regarding the health of an important sector of the red kite wintering population. Synthesis and applications. Conservation of wintering red kites in Spain should involve management to promote the recovery of populations of wild prey, especially wild rabbits, and measures to allow free-range livestock carcasses to be placed in the countryside for scavenger elimination without posing a risk from the spread and transfer of disease, especially bovine spongiform encephalopathy (BSE). Periodic inspections by management agencies should ensure that meat originating from stabled livestock and disposed of in refuse dumps does not pose major hazards for avian scavengers. The risk to scavengers from ingestion of residues of veterinary drugs, pathogen acquisition and gut flora alteration, arising from disposal and accumulation of infected carcasses and rotten meat in refuse dumps, must be carefully monitored and managed.