Diagnosis of feline platynosomosis: case series and literature review.

Platynosomosis is a parasitic disease of cats and other animal species, caused by trematodes of the genus Platynosomum. These flukes can infect the liver parenchyma, biliary ducts, and gallbladder. In cats, this parasite is most commonly associated with inapparent infections; however, clinical infections with cholangiohepatitis have also been described. Platynosomum spp. are also related to the development of cholangiocarcinoma. Here, we describe 6 cases of cats parasitized by Platynosomum illiciens. Four of these cats were also infected with feline leukemia virus; 5 were parasitized with Spirometra mansoni, 4 with Ancylostoma sp., and 1 with Dirofilaria immitis. Clinical and coprologic evaluations were performed on all individuals. Five cats had severe clinical decline, which prompted euthanasia. On autopsy, these 5 animals had diffuse cholangiohepatitis with intralesional trematodes. Gross and microscopic lesions, parasite and egg morphology, PCR, and DNA sequencing with a Bayesian inference phylogenetic tree and haplotype network confirmed a diagnosis of platynosomosis caused by P. illiciens.