Parasites of the laboratory woodchuck (Marmota monax).

: The parasite burden of captive and colony-born woodchucks maintained in laboratory animal facilities was determined and compared to woodchucks recently trapped. Microfilariae of Ackertia marmotae in blood or dermis were most commonly observed in trapped woodchucks. There was a linear decrease in woodchucks positive for microfilariae after introduction in the laboratory colony, but even after 39 months, 53% were positive. Microfilaremia or microfilariderma were never observed in colony born woodchucks. Eggs or oocysts of Obeliscoides cuniculi, Citellina triradiata and Eimeria sp. were found by fecal flotation. The O. cuniculi population declined exponentially in captive woodchucks following colony entry, and this nematode was never found in colony-born woodchucks. However, low rates of infection with Citellina and Eimeria sp. were found in the colony-born group. Ixodes cookei, Oropsylla sp., and Androlaelaps sp. ectoparasites were observed commonly in recently trapped woodchucks, but were not present in any woodchucks maintained in the colony. Clinical disease associated with parasitic infection was not observed.