[A study of seroprevalence of leptospirosis in Gunma Prefecture, 2010].

Objectives: Leptospirosis is a zoonotic infection; water and soil are contaminated with Leptospira through the urine of rodents carrying the agent in the kidneys, and then the infection is established percutaneously or orally. In November 2009, the first notification of leptospirosis was submitted in Gunma Prefecture. It is important to clarify the current status of the leptospirosis epidemic in the prefecture and to enlighten residents and healthcare professionals. Hence, we examined the infection status of leptospirosis in residents living near the residence of the patient in this study.

Subjects: SUBJECTS were residents of Isesaki City, Gunma Prefecture, aged 40-64 years and who had undergone a specific health examination (mass health examination) for insured persons under Japan's National Health Insurance on April 23 and 26, 2010.

Sample Size: We randomly selected 100 subjects from residents who underwent the examination, and antibody titer against leptospirosis was measured. Testing method: Measurement of the antibody titer was commissioned to the National Institute of Infectious Diseases. Microscopic agglutination tests using 6 serotypes of living Leptospira that are widely distributed to the main islands of Japan were performed.

Results: One hundred eighty subjects underwent the examination on the 2 days, and 174 of them consented to participate in the study. Serum antibody titer was measured in 100 patients, and the results were all negative.

Conclusion: Leptospirosis is a treatable disease when it is diagnosed; therefore, early diagnosis and treatment is important. Mild cases may be missed. Awareness of leptospirosis is low among healthcare professionals in the prefecture. Although it is a rarely infectious disease, it is important to make leptospirosis known to medical associations in the prefecture and to conduct training workshops and similar activities.