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 .