Leishmaniasis in China-Present Status of Prevalence and Some Suggestions on Its Control

Abstract

According to the data collected from 1990~1999,visceral leishmaniasis (VL) was prevalent or sporadically distributed in 43 counties of 6 western provinces/autonomous regions (P/A) in China, including Xinjiang, Gansu, Sichuan, Shaanxi, Shanxi and Inner Mongolia. Furthermore, local inhabitants of non endemic counties who had visited endemic area for business or travelling were reported to contract the disease. More than 2 629 new VL cases were discovered in above six P/A from 1990~1999.\;In Xinjiang, VL was mainly prevalent in old oases of plain region in Kashi where the disease was anthroponotic, peridomestic Ph. longiductus was detetced to be the major vector in the oases. The prevalence of the infection is sporadic in desert region, wild species Ph. wui and Ph. alexandri being the vector. In Gansu, Sichuan, Shaanxi and Shanxi Provinces, VL was distributed in mountainous and hilly regions, where wild or semiwild species Ph. chinensis being the vector, with canine visceral leishmaniasis (CVL) as the source of infection. Detection of antibody to Leishmania donovani for family members of VL patients in Wudou County, Gansu Province revealed a positive rate of 21.0%, indicating a high proportion of occult infections occurring in the affected households in situ. VL merely sporadically existed in Ejni Banner, Inner Mongolia and wild species Ph. wui was found to be the vector.\;The survey conducted in pilot sites in mountainous area of Sichuan Province demonstrated that extinction of infected dogs and prohibition of maintaining domestic dogs could markedly reduce the prevalence of VL. And deltamethrin bathing of dogs would obtain promising results in interruption ofthe disease.\;The results of surveillance in formerly endemic areas in the eastern provinces including Shandong, Henan, Jiangsu and Hubei showed that there were no new autochthonic VL cases for 16~27 years, and Ph. chinensis the vector was hardly found, demonstrating desirable and consolidated consequences of intervention.\;Cutaneous leishmaniasis (CL) induced by L.infantum only occurred in Karamay, Xinjiang, showing prevalence of 1.0%~1.6%. In view of the fact that prevalence of CL doesn't exhibit family aggregation, its vector Ph. wui is a wild species and natural infection rate of the sandfly species in the wild is rather high, CL is assumed to be a zoonotic disease.\;Subsequently, on the basis of this paper, six points of suggestion on locality based control measures for different kinds of endemic areas of leishmaniasis were presented.