Prevalence of Platynosomum fastosum infection in free roaming cats in northeastern Brazil: Fluke burden and grading of lesions.

The objective of this paper was to investigate prevalence and parasite load of the trematode Platynosomum fastosum infection and the risk of developing cholangitis/cholangiohepatitis among infected domestic cats in a city of northeastern Brazil, and to characterize the influence of fluke burden in the formation of lesions in liver and gallbladder. A total of 141 cats was necropsied and examined for the presence of P. fastosum. The observed prevalence was 42.6% (60/141, 95% CI=34.2-50.9). Parasite load varied from 1 to 219 flukes per animal. Adult cats were more frequently infected than kittens (p<0.01). Risk of cholangitis was about three times higher in infected animals (RR=3.23, 95% CI=2.01-5.07, p<0.01). Centrolobular congestion, portal cholangitis and cholestasis was significantly more common in infected as compared to non-infected cats (p<0.01). Similarly, fibrosis, cholangitis and mucous gland hyperplasia were significantly more prevalent in the bile duct of infected animals (p<0.01). Mild fibrosis and cholecystitis were observed principally in infected cats. Hyperplastic precursor lesions of cholangiocarcinoma were observed, but no solid tumor was diagnosed. These results reveal high prevalence of P. fastosum in free roaming cats in northeastern Brazil, with increased risk of liver disease.