Prenatal infection of the Rocky Mountain bighorn sheep (Ovis c. canadensis) of Alberta with the lungworm Protostrongylus spp.

First- and third-stage (infective) larvae of Protostrongylus spp. were recovered from the livers of four fetuses of the Rocky Mountain bighorn sheep of Alberta. This record suggests a more cosmopolitan distribution of prenatal infection with lungworms in bighorn sheep than suspected previously.