We encountered three cases of
paragonimiasis westermani caused by ingestion of Chinese freshwater crabs. All patients are Chinese living in Japan who had a history of eating raw Shanghai crabs at the Chinese restaurant owned by one of them. A few months later they complained of
cough,
chest pain and
dyspnea. On examination, their peripheral blood showed a remarkable increase in eosinophils. Chest radiographs revealed the presence of
pleural effusion in all cases, and of
pneumothorax in one. Pleural fluid obtained from two cases showed an increased number of eosinophils, an elevated LDH, and a decreased
glucose level. Paragonimus westermani was determined in a positive serum antibody test. The patients were treated with
praziquantel for 3 days at a daily dosage of 75 mg/kg and their symptoms were relieved, but one case needed additional treatment with
praziquantel for 3 days at a daily dosage of 50 mg/kg because of sustained
pleural effusion and a persistently high antibody titer. Most cases of
paragonimiasis found in Japan have been sporadic and individual, but three cases occurring close to each other in both distance and time have recently been reported. Such multiple
infections are likely to increase because of the gourmet food boom and the internationalization of eating habits.
Paragonimiasis must be kept in mind in the differential diagnosis of cases of
pleural effusion with
eosinophilia. We would therefore like to emphasize the importance of the detection of parasite-specific
antibodies and of careful history-taking from patients.