The epidemiological characteristics of visceral leishmaniasis in China from 2005-2009.

Objective To describe the epidemiological characteristics of visceral leishmaniasis (VL) in China and provide evidence for developing a VL control strategy.Methods All data were obtained from the Disease Reporting Information System of the Chinese CDC,and the distribution,peak season of onset,and age of onset in cases of VL were described and compared among different types of VL.Results (1) The incidence of VL in China tended to increase from 2005 to 2009,with growing numbers of reported cases and counties affected.The number of reported cases dramatically increased 159% in 2008 compared to the previous year as a result of a VL outbreak in Jiashi County,Xinjiang Uygur Autonomous Region.(2) The incidence of VL was limited to several areas.The cases reported from Xinjiang,Gansu,and Sichuan provinces accounted for 97.8% of all VL cases in China.(3) There was a significant difference in age distribution among canine VL,anthroponotic VL,and VL originating from wild animals (P0.05).For VL originating from wild animals,79% of individuals affected were under 1 year of age;for anthroponotic VL,0.7% were under 1 year of age.For anthroponotic VL,the age of onset peaked for individuals 3-4 years of age.For canine VL,however,the age of onset peaked for individuals under 1 year of age and the number of reported cases declined with age.(4) The majority of affected individuals ages 2 and up were reported from March to June,and there were no seasonal characteristics for affected individuals under 2 years of age (except for individuals in Jiashi County) (P0.05).The peak season of onset was from September to February for cases identified in an outbreak in Jiashi County.Conclusion The incidence of VL has increased in China,and the epidemiological characteristics of various types of the disease differed significantly.Based on epidemiological characteristics in different areas,adequate steps should be taken to enhance VL control and prevention and to control the outbreaks and incidence of VL in western China.In addition,the epidemiological factors and characteristics of VL should be studied further in different areas.