Surveillance of leptospirosis in Longyou, Zhejiang,2007-2011

Objective To understand the epidemiological characteristics of leptospirosis in Longyou county from 2007 to 2011 and provide scientific evidence for the development of prevention and treatment strategies. Methods Descriptive epidemiological analysis was conducted on the incidence data of leptospirosis in Longyou during this period and the serum samples collected from clinic diagnosed patients and host animals in Longyou were tested by microscopic agglutination test. The kidney samples of mouse, frog, duck, swine and the urine samples of bovine were collected for pathogen culture. The kidney samples of mouse and frog were collected to detect leptospira by PCR. Results The average annual incidence of leptospirosis was 0.40/lakh. Most patients were middle-aged farmers, and more female patients were reported than male ones. The serum antibodies detected in the patients were mainly to L. icterohemorrhagie. The disease mainly occurred in summer and autumn. The cases were distributed in all townships, but the case number in Miaoxia township was highest. Twelve strains of leptospira were detected, most of which belonged to L. autumnalis (83.33%).The positive rate of serum of host animals was 41%, and the main strains were L. icterohemorrhagie (51.22%) and L. autumnalis (39.02%). The positive rate of the kidney samples of mouse and frog was 28.07% by PCR. Conclusion The incidence of leptospirosis was high in summer and autumn in Longyou, and middle-aged farmers were affected mostly. The serogroups of leptospira detected in host animals and patients were not consistent. It is necessary to further strengthen the surveillance of leptospirosis both in human and in host animals.