The effect of temperature on the immune response of cat fleas (Ctenocephalides felis)

REU Fellow: Jaya Martin, Hiram College

Mentor: Dr. Lisa Brown

Fleas are carriers of pathogens that cause diseases in humans and animals. Although fleas are susceptible to infections, they are not willing hosts. Fleas possess an immune system that serves to resist or limit pathogen replication; however, the efficiency of their immune response is dependent on several factors, including temperature. In the midst of climate change, we hypothesize that fleas that experience higher temperatures are more susceptible to infection. To test this hypothesis, we maintained cat fleas (Ctenocephalides felis) at three different temperatures (24^oC, 27^oC, 30^oC), and measured the intensity and prevalence of bacteria (Serratia marcescens) following an oral infection. Our results show that intensity of bacteria between infected fleas does not increase as temperature increases; however, as temperature rises, the prevalence of an infection among fleas does increase. Overall, the current study provides support that variations in temperature can influence the susceptibility of fleas to an infection, which ultimately affects their capacity to transmit pathogens.