Molecular Identification of a Case of Paragonimus pseudoheterotremus Infection in Thailand

Abstract

Paragonimiasis is an important food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Southeast Asia, Paragonimus heterotremus is the only proven causative pathogen. Recently, a new Paragonimus species, P. pseudoheterotremus, was found in Thailand. This species is genetically similar to P. heterotremus and is considered as a sister species. However, infectivity or pathogenicity of P. pseudoheterotremus to humans remains unclear. We report the first confirmed human pulmonary paragonimiasis case caused by P. pseudoheterotremus infection. After polymerase chain reaction/sequencing of the DNA extracted from Paragonimus eggs in the sputum of the patient, partial internal transcribed spacer 2 and cytochrome c oxidase subunit 1 sequences were approximately identical (98-100%) with those of P. pseudoheterotremus. For P. heterotremus, the partial internal transcribed spacer 2 sequence was approximately identical (99-100%), but the partial mitochondrial cytochrome c oxidase subunit 1 sequence showed a similarity of 90-95%.