Ovine nematodes in wild lagomorphs in Australia and first record of Trichostrongylus rugatus in free living lagomorphs

Gastrointestinal parasites are a major problem for sheep graziers and anthelmintic resistance has been reported worldwide. Given that in experimental circumstances, sheep helminths are able to develop in rabbits and hares, and that hares are very mobile and sympatric with sheep in many regions of Australia, free-living lagomorphs were investigated regarding carriage of ovine nematode parasites under field conditions. We performed specific worm counts in the gastrointestinal tracts of 88 rabbits and 110 hares. We revealed that ruminant worms are common in hares (prevalence 79%) and that they are occasionally found in rabbits (9%). Statistical analyses showed that the ruminant worm Trichostrongylus colubriformis occurred frequently in hares whilst rabbits were commonly infected with lagomorph-specific Trichostrongylus retortaeformis. Detection of the ovine worm Trichostrongylus rugatus is reported for the first time in wild lagomorphs. The potential for cross-transmission between hares and sheep in the natural environment is much more prevalent than previously believed.