Massive visceral pentastomiasis caused by Porocephalus crotali in a dog.

The testes of a 5-year-old, male, crossbred Schnauzer dog were the indicator organs for detection of massive pentastomiasis. Necropsy revealed numerous additional encysted parasites within the mesenteric lymph nodes, omentum, liver, sub-serosa of the small and large intestines, mesentery, and lungs. The nymphs had a pseudosegmented body, containing large eosinophilic glands and a chitinous cuticle with characteristic pores. Their hook configuration was consistent with that of Porocephalus. A pentastomid-specific 18S rRNA polymerase chain reaction (PCR) was designed and used to amplify template for sequencing. The sequence of the PCR product was 99.7% homologous with the reference sequence for P. crotali. This pentastomid parasite has been reported in North American snakes of genera Crotalus and Agkistrodon. Mammals are intermediate hosts, and snakes are the definitive hosts. Porocephalus crotali has been reported in dogs only once, and molecular methods have not been used previously to identify the species in clinical pentastomiasis.