Pleuropulmonary Infection by Paragonimus westermani in the United States: A Rare Cause of Eosinophilic Pneumonia After Ingestion of Live Crabs

Infections caused by the parasite Paragonimus westermani are endemic to Southeast Asia. Most infections reported in the United States are among immigrants who acquired the disease abroad. Due to the nonspecific nature of its presentation and rarity in the United States, the diagnosis may first be suggested by the pathologist on biopsy review. Definitive diagnosis may need serologic testing for confirmation. We report 4 cases of pleuropulmonary disease caused by United States-acquired P. westermani, which were identified in the consultation files of the authors. Patients (3 men and 1 woman; aged, 20 to 66 y) presented with pulmonary complaints and chest imaging abnormalities including cavitary infiltrates (2), lung mass (1), pleural effusion (1), and pneumothorax (1). Biopsies showed chronic eosinophilic pneumonia and organizing pneumonia in all cases. Other pathologic findings included granulomatous inflammation with geographic necrosis (3), vasculitis (3), and pleuritis (3). Paragonimus organisms and/or eggs were identified in 2 cases. Serologic studies were positive for P. westermani in 3 cases (2 enzyme-linked immunosorbent assay and 1 immunoblot). Three patients ate live crabs at sushi bars (including crabs in martinis, a previously unreported mechanism for infection). In 1 patient, the source of infection was uncertain. Paragonimiasis should be considered in the differential diagnosis of patients with eosinophilic pleuropulmonary disease in the United States. Although eosinophilic pneumonia was a consistent finding, the biopsies may be nonspecific as the organisms and/or eggs are not always visualized. Unusual features include marked pleuritis, foci of geographic necrosis and granulomatous vasculitis. A history of ingestion and targeted serologies are the keys to diagnosis.