Complexity of Paragonimus westermani Diagnosis: A Review of Case Reports in Asia

Abstract

Paragonimiasis caused by Paragonimus westermani is a foodborne trematode infection that primarily affects the lungs but may involve multiple organs, often mimicking other diseases and leading to frequent misdiagnosis. This systematic review aimed to summarize the epidemiology, clinical manifestations, diagnostic approaches, and treatment outcomes of P. westermani infection, with emphasis on its diagnostic challenges. A literature search was conducted following PRISMA guidelines across PubMed, ScienceDirect, Google Scholar, and ResearchGate for case reports published between January 2014 and August 2024 in Asia. Eligible studies included peer-reviewed English-language reports with confirmed      human infections. Forty cases met the inclusion criteria. The majority of infections were associated with consumption of raw or undercooked freshwater crabs (55%). Pulmonary and pleural involvement represented the most common presentation (62%), frequently misdiagnosed as pneumonia, tuberculosis, or lung malignancy, while extrapulmonary cases involved the brain, abdomen, skin, and other organs. Diagnosis was primarily established through histopathologic identification of eggs or worms (60%) and serologic testing (45%). Praziquantel therapy resulted in favorable outcomes in most cases. These findings highlight the diverse clinical spectrum of P. westermani infection and underscore the importance of clinical awareness, exposure history, and appropriate diagnostic evaluation to prevent misdiagnosis and ensure timely treatment.