Prevalence of Hepatic Parasites in Korean Wild Rats (Rattus norvegicus) and Their Association With Pulmonary Arteriolar Medial Hypertrophy

Abstract

C hepatica, an important zoonotic parasite, and C fasciolaris are common parasites in rodents. In rodent livers, C hepatica causes sequential morphologic changes that are designated as early, intermediate, or late phase, and C fasciolaris forms cysts surrounded by fibroplasia and granulomatous inflammation. The present study describes the prevalence of these parasites and associated liver and lung lesions in wild rats ( Rattus norvegicus) living around pig farms in South Korea. Selected parenchymal organs, including liver and lung, of 89 wild rats were examined. Of 89 rats, 28 (31.5%) were infected with either C hepatica or C fasciolaris or with both parasites. Severe medial hypertrophy of small arterioles was observed in the lungs of 11 of the 28 parasite-infected rats ( P < .01). The pulmonary arteriolar hypertrophy in the rats infected with C hepatica was strongly associated with early and/or intermediate phases (88.8%) of morphologic change in the livers ( P < .01). As such, this report is the first to suggest a significant association between parasite-induced hepatitis and pulmonary arteriolar hypertrophy in rodents. Further studies are warranted for the use of C hepatica–infected rats as an animal model to explore the underlying mechanisms of portopulmonary hypertension in humans.