Characteristics of natural infections of the stomach worm, Obeliscoides cuniculi (Graybill), in lagomorphs and woodchucks in Canada.

ABSTRAd:T: Wild lagomorphs and woodchuicks collectet! predominantly ins soutthsemnu Oumtanio, Caumatla svene examined for subspecies of Obeliscoides cuniculi (Graybill). Obeliscoides cuniculi multistriatus svas fouiuid in snowshoe hares (Lepus americanus). Obeliscoides cuniculi cuniculi svas fouust! imucottoumtail rabbits (Syl- vilagus floridanus), European hares (Lepus capensis) and 'svoodchucks (Marmota nuonax). Prevalenice of Obeliscoides cuniculi multistriatus in sno'svshoe hanessvas 100% atsd mean intcnssitv (amid range of intensity) was 760 (9-4,198) in Lindsay, Ontario in 1980. Mean intensity in hares varied trimonthly. The highest mean intensity of worms occurred in spring when most worms were adult. Transmission occurred mainly in spring. Most worms present in fall (70%) and winter (54%) were fourth stage. Immature fifth-stage and gravid females were present in hares during fall and winter. Prevalence and mean intensity of 0. c. cuniculi in cottontails was 15% and 29 (1-118). Prevalence and mean intensity of 0. c. cuniculi in woodchucks was 6% and 56 (16-118). European hares were infected with 0. c. cuniculi, prevalence was 10% and mean intensity was 60 (36-83). In Ontario woodchucks and European hares were common in areas frequented by cottontail rabbits and probably acquired sporadic infections of 0. c. cuniculi from infected cottontails.