Additionally, two other hares from the same areas also showed a Capillaria hepatica infection. The remaining 85 animals examined within this study over a period of three years, were not affected. The reason for the local and temporary limitation of the infection remains unknown. Rats and mice are the usual hosts of Capillaria hepatica. The parasite shows a direct life cycle with both female and male worms in the liver parenchyma.
Eggs remain in the liver until the host is devoured or the liver undergoes postmortem decomposition.
Antemortem diagnosis is only possible by liver biopsy. The parasites are not highly pathogenic. Their importance is gathered by their ability to infect other mammals. Infection is usually inapparent in rodents, and is uncommon in laboratory-reared animals because of the unusual requirements of the life cycle. Their musculature is coelomyarian, polymyarian but may be inapparent.