Livestock Drugs and Disease: The Fatal Combination behind Breeding Failure in Endangered Bearded Vultures

Blanco, Guillermo; Lemus, Jesús A.

The link between veterinary drugs and livestock disease should be further investigated in scavenger species, because both threats may concur in food and because the immunodepressive effects and other physiological alterations caused by drugs may facilitate the acquisition and proliferation of pathogens [6, 11, 21] . Given that both threats acting together may greatly contribute to breeding failure decreasing productivity, their potential as stochastic factors with potentially devastating effects increasing the risk of extinction should be not overlooked in current conservation programs of bearded vultures and other scavenger species, especially regarding dangerous veterinary drugs and highly pathogenic viruses frequently infecting poultry. In addition, restricted geographic distribution and low genetic variability [57] common to many threatened species may favour pathogen transmission and reduce the ability of a naïve immune system to fight against novel pathogens [3, 28, 58] , making them especially vulnerable to the potential cross-species transmission of highly virulent virus strains able to cause important outbreaks, as reported in poultry [59] [60] [61] .