Scavenger birds exploiting rubbish dumps: Pathogens at the gates

Different bacteria are present in rubbish dumps used as food resources by various bird species. Birds may be good indicators of the presence of zoonotic diseases in these sites since they can be infected with zoonotic pathogens by foraging on organic waste, and can also act as carriers. We studied if foraging in rubbish dumps increases the occurrence of Salmonella spp. and Chlamydia psittaci in American black vultures (Coragyps atratus, hereafter black vultures) from northwest Patagonia. We compared these pathogens isolated from or detected in cloacae and oropharynx swabs in two different groups of black vultures: individuals trapped in (a) the Patagonian wild steppe and (b) in a rubbish dump. We found that black vultures are colonized by Salmonella spp. (particularly Salmonella enterica serotypes Typhi, Paratyphi A, Salmonella enterica subsp. arizonae) and Chlamydia psittaci. Interestingly, there were differences in the prevalence of Salmonella spp., especially Salmonella Typhi, between individuals foraging in the rubbish dump and the steppe, but not in the prevalence of Chlamydia psittaci. The pathogens isolated from black vultures may impact their health status but could also have health impacts in other bird species and even humans. In fact, Salmonella Typhi can cause severe disease in humans leading to death. Our results are globally relevant given that bacterial infections from rubbish dumps may affect different species exploiting these sites around the world. There is a need to better control pathogens in rubbish dumps to avoid the risk of infecting wildlife, which could act as potential dispersers and reservoirs of these pathogens.