A viral mimic increases body temperature but does not affect mass or inflammation in a wild frugivorous bat

Alexis Heckley , Valeriia Bohodist, Camilo Calderon, Alona Prylutska , Maryna Yerofeieva, Kateryna Zemliana, Rachel Page, Ralph Simon, Daniel J Becker 

The acute phase response is a component of innate immunity that helps fight infections. Understanding variation in this response is particularly critical in bats, which can be asymptomatic hosts of pathogens that cause disease in other animals. Although bats are most famously tolerant of viruses, research on the bat acute phase response has focused predominantly on bacterial antigens. To improve understanding of bat viral responses, we challenged wild Seba’s short-tailed bats (Carollia perspicillata) with a viral mimic (polyinosinic:polycytidylic acid; poly:IC). We injected nine bats subcutaneously with 2 mg/kg of poly:IC (n = 3), 5 mg/kg of poly:IC (n = 3), or phosphate buffered saline (n =3). Over the next 24 hours, we measured body temperature hourly and collected body mass and blood smears for leukocyte counts every four hours. Regardless of dose, poly:IC-challenged bats had higher body temperatures compared to control bats but did not exhibit leukocytosis or reduced body mass. These findings improve understanding of how wild bats physiologically respond to viral challenges. Moreover, in showing that as little as 2 mg/kg of polyI:C can induce a febrile response, our study provides a framework to facilitate future investigations into causes and consequences of wild bat viral responses.