Paragonimiasis in Japan: a twelve-year retrospective case review (2001-2012).
OBJECTIVE
Paragonimiasis, or lung fluke infection, is a food-borne parasitic disease caused by infection with trematodes belonging to the genus Paragonimus. Although paragonimiasis was once considered successfully controlled in the 1970s, new cases began to emerge in the late 1980s. To apprehend the current-day situation of the re-emergent cases of paragonimiasis in Japan, we conducted a retrospective review of 443 patients who were referred to our laboratory and diagnosed as having paragonimiasis during 2001-2012.


METHODS
Patients were diagnosed as having paragonimiasis based primarily on immunodiagnostic methods in addition to clinical, laboratory, and radiographic findings. Patient data were extracted from consultation sheets from attending physicians and were analyzed.


RESULTS
Majority of the patients were residents of Kyushu Island. However, a substantial number of cases were also from other parts of Japan. Immigrants (mostly from China, Thailand, and Korea) accounted for a quarter of the cases. Native Japanese contracted paragonimiasis by consuming wild boar meat or freshwater crabs, whereas immigrants contracted the infection almost exclusively by consumption of freshwater crabs. Eosinophilia and elevated serum IgE levels were found in around 80% of the patients. Parasite egg detection was documented only in 11.7% of the cases, showing the reliance on serological tests for diagnosing paragonimiasis in current clinical practice.


CONCLUSIONS
Paragonimiasis remains a public health issue in Japan, and the situation should be closely monitored.
Division of Parasitology, Department of Infectious Diseases, Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Japan.
Eiji
E
Nagayasu
Ayako
A
Yoshida
Amy
A
Hombu
Yoichiro
Y
Horii
Haruhiko
H
Maruyama
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000818:Animals; D003386:Brachyura / Q000469:parasitology; D002681:China / Q000208:ethnology; D005260:Female; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D010237:Paragonimiasis / Q000453:epidemiology* / Q000209:etiology; D056910:Republic of Korea / Q000208:ethnology; D012189:Retrospective Studies; D012698:Serologic Tests; D034421:Sus scrofa / Q000469:parasitology; D013785:Thailand / Q000208:ethnology
D007073:Immunoglobulin E