Paragonimiasis.

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species. Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex. Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 6.1).

Epidemiologic evaluation of pulmonary paragonimiasis in Japan using a Japanese nationwide administrative database.

BACKGROUND: Paragonimiasis is a parasitic disease primarily contracted through consumption of undercooked freshwater crustaceans or wild boar meat. Large-scale nationwide epidemiological data on paragonimiasis are lacking. In this study, we aimed to investigate the nationwide epidemiology of hospitalized patients with paragonimiasis in Japan using a comprehensive nationwide Japanese administrative database. METHODS: We evaluated the Japanese Diagnosis Procedure Combination (DPC) data of patients diagnosed with pulmonary paragonimiasis between April 1, 2012 and March 30, 2020. The patients' address and information, including age, sex, treatment (medication: praziquantel; surgery: open thoracotomy or intracranial mass extirpation), Japan coma scale, comorbidities, and length of hospital stay, were extracted. RESULTS: Of the 49.6 million hospitalized patients, data were extracted on 73 patients with paragonimiasis, of whom 36 were male and 37 were female. The mean age was 49.7 years and the mean length of stay was 12.5 days. The most frequent comorbidity was pleural effusion (31.5 %), followed by pneumothorax (13.7 %). The sites of ectopic paragonimiasis in organs other than the lung included the liver (5.5 %), skin (4.1 %), and brain (2.7 %). Geographically, most patients were from the Kyushu region (54.8 %), followed by the Kanto region (22.0 %). Fukuoka Prefecture had the highest number of patients (22.0 %) by prefecture. During the study period, an average of 9.1 patients/year were hospitalized with lung paragonimiasis in Japan. CONCLUSION: Paragonimiasis has not completely disappeared in Japan; thus, physicians should be aware of paragonimiasis in the Kyushu region, especially in the Fukuoka Prefecture.