Meeting Abstract

P2.75  Tuesday, Jan. 5  Interactions between parasites: tapeworms alter life history of nematodes during co-infection in the laboratory mouse host CLARK, Paul, R.*; KRISTAN, Deborah, M.; CA State Univ. San Marcos clark146@cougars.csusm.edu

Wild animals often host multiple parasite species simultaneously. One parasite may alter the life history of another parasite, especially if they occupy the same physical space in the host. We tested if the bile duct tapeworm (Rodentolepis microstoma) could alter the distribution, size and reproduction of the intestinal roundworm Heligmosomoides bakeri using the laboratory mouse (Mus musculus) host. We used three co-infection experimental groups (an initial infection with R. microstoma followed by H. bakeri, an initial infection with H. bakeri followed by R. microstoma, or both parasites given to the host at the same time) and one group with H. bakeri infection only as a control. We found that presence of R. microstoma did not affect the total number of H. bakeri worms (p=0.079) or H. bakeri sex ratio (p=0.283). However, H. bakeri occupied more distal locations in the mouse small intestine if R. microstoma was given to the host first (p=0.004). For female H. bakeri, worms grew longer (p=0.016) and produced more eggs in vivo (p<0.0001) and in vitro (p<0.0001) when from a host where H. bakeri was given first or was alone in the host compared to infections where R. microstoma was given first. These data show that life history traits of parasites may vary due to presence of other parasite species in the host. Changes in parasite growth, reproduction, and distribution within host tissue can have important consequences to host-parasite transmission dynamics and to physiological changes experienced by the host itself.