Bovine hepatogenic photosensitization caused by chronic fasciolasis

Abstract

Hepatogenic photosensitization in cattle is a pathology that can be caused by several diseases, such as chronic fasciolasis, as a consequence of the damage provoked, causing an inability of the liver to excrete photodynamic agents. Fasciolasis is a disease of high prevalence in Uruguay. Photosensitization is one of the clinical signs that can be observed in chronic fasciolasis, based on its ability to produce liver fibrosis, cholangitis with biliary stasis. In this work, two outbreaks of hepatogenic photosensitization in cattle are described in the counties of Tacuarembó and Soriano (Uruguay). The disease affected a herd of Hereford and crossbreed cows, and a herd crossbreed heifers. In both outbreaks animals were grazing in humid woodlands. The main clinical signs observed were weight loss, crusting and peeling of the nose, photophobia, sialorrhea and eye shifts. Main macroscopic findings at necropsy were bilateral necrotic dermatitis of the eyelids, ulcers on the ventral side of the tongue. Thickening of the liver`s Glisson capsule, diffuse hepatic fibrosis and chronic cholangitis with canalicular calcification. Histopathology showed liver fibrosis and canalicular obstruction with the presence of Fasciola hepatica as main lesions. The clinical signs of hepatogenic photosensitization observed in animals are related to the described liver disorders caused by F. hepatica