Pernicious liaisons: antibiotic-depressed immune response of a livestock micropredator, the common vampire bat (Desmodus rotundus)

Abstract Antibiotics are pharmaceutical products with the potential to affect the immune performance of wildlife. Wildlife species might incorporate antibiotic residues in their system when feeding on livestock treated with these chemicals. One of the most studied interactions of livestock with wildlife is that established with the common vampire bat ( Desmodus rotundus ), which predates on livestock. We tested the effect of clindamycin on the humoral and cellular acquired immune responses of common vampire bats captured in the wild in Mexico. We hypothesized that both cellular and humoral acquired immune responses would be negatively affected after bats were exposed to clindamycin for 15 days. We measured local inflammation (swelling index = SI ) and serum immunoglobulin concentration (IgG) after the repeated application of phytohemagglutinin (PHA) in bats treated with clindamycin and in a control group that did not receive the antibiotic. PHA is a plant lectin that induces mitosis in the effector cells of cellular-mediated immunity. We expected that antibiotic-exposed bats would present a weaker inflammatory response and that their IgG serum levels would not increase at the same rate after three consecutive injections of PHA than bats in the control group. Mean SI after the second injection of PHA was higher than that after the first injection only in bats in the control group. No significant difference was found in SI after the third injection with respect to the first injection in both the control and the experimental group. Mean IgG concentration was higher after the third injection than before the first injection only in vampire bats not treated with antibiotic. Our study shows the negative effect that exposure to anthropogenic chemicals generates on wildlife capacity to maintain a healthy immune system.