Unlike trematodes, this parasite resides in the hepatic parenchyma. The primary hosts of the adult stage are rodents. However, infections are also occasionally observed in dogs. The adult deposits its eggs within the liver and the eggs escape when the primary host is eaten by a predator. Ingested eggs pass through the gastrointestinal tract of the predator and are released into the environment.
Mature larvae develop which are then eaten by a suitable host.
In the present case, the pup was a stray and likely foraging for food before being adopted by the local animal control agency. Both this pup and its litter mate were also diagnosed with canine distemper. Hepatitis, granulomatous and eosinophilic, multifocal to coalescing, moderate, with aphasmid adults and eggs, German Shepherd Dog cross, canine, etiology- consistent with Capillaria hepatica. Adults and eggs are randomly located due to the parasite's parenchymal habitat. The eggs do not develop further unless freed from the liver and exposed to air.