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

Antibiotics are pharmaceutical products that have the potential to affect the immune performance of wildlife. Wildlife species might incorporate antibiotic residues in their system by feeding on livestock treated with these chemicals. One of the most important interactions of livestock with wildlife is that established with the common vampire bat (Desmodus rotundus). We used vampire bats as an ecologically relevant model to test the effect of antibiotics on wildlife immune response. We tested the effect of clindamycin on the humoral and cellular acquired immune responses of common vampire bats captured in the wild in southern Mexico. We expected that both cellular and humoral acquired immune responses would be negatively affected after bats were exposed to clindamycin for several days. We measured local inflammation and serum immunoglobulin concentration (IgG) after the repeated application of phytohemagglutinin. We expected that antibiotic-exposed bats would present a weaker inflammatory response to a second injection of PHA and that their IgG serum levels did not increase to the same rate after the third PHA injection. Antibiotic-treated vampire bats exhibited weaker inflammatory response to the repeated PHA treatment: induced swelling was ~30% larger after the second injection than that after the first injection, whereas swelling after the second injection in antibiotic-treated bats was ~10% lower than after the first injection. There was an increase of IgG serum levels following three consecutive PHA injections but it occurred only in vampires that did not receive the antibiotic: IgG serum levels of control individuals increased ~90% over pre-injection values, whereas this value was ~15% lower in vampires treated with antibiotic. Our study adds to previous evidence pointing to the negative effect that exposure to anthropogenic chemicals generates in wildlife capacity to maintain a healthy immune system and warrants further work on the relationship of potential antibiotic-induced changes in gut microbiota and immune response. ### Competing Interest Statement The authors have declared no competing interest.