First report of Paragonimus mexicanus infection in a domestic cat from Costa Rica

Abstract Paragonimus is the only genus in the family Troglotrematidae. Dogs, cats and other mammals may become infected by consuming crabs or shrimp harbouring metacercariae. A 1.11‐year‐old cat was presented with chronic coughing episodes. Thoracic radiography and ultrasonography suggested diffuse pneumonia. Cytology from a pulmonary granuloma and faecal examination revealed numerous trematode eggs (50–100 µm) consistent with Paragonimus spp. Molecular analysis of faecal DNA confirmed 100% nucleotide identity with Paragonimus mexicanus metacercariae previously reported from freshwater crabs in Puntarenas, Costa Rica. Antiparasitic therapy combining praziquantel, pyrantel and mebendazole resolved clinical signs. This case highlights the importance of including paragonimiasis in the differential diagnosis of cats with chronic respiratory disease in Central America, where aquatic intermediate hosts and wild reservoirs are abundant, even in peri‐urban settings.