Domestication of American Cutaneous Leishmaniasis

全世界皮肤利什曼病的发病率平均每年约为125万例。在美洲，过去十年中，以前占主导地位的森林传播周期已成为新兴的国内传播周期的次要因素。最近，在低流行率（每年<50例）的农村地区发生了几次美国皮肤利什曼病（ACL）暴发（每次1000 - 2000例）。州和地方监测资源的可用性，以及毗邻的非流行区作为控制地点的可用性，提供了一个独特的机会，以确定导致(a)流行病的建立和(b)传播周期的国内性的因素。在此制定的项目侧重于一个地区，该地区的流行病病例达到了100 000例

Worldwide incidence of cutaneous leishmaniasis averages approximately 1.25 million cases per annum. In the Americas, the formerly dominant sylvatic cycle of transmission has become secondary to an emerging domestic transmission cycle within the past decade. Very recently, several outbreaks of American Cutaneous Leishmaniasis (ACL) have occurred (1,000-2,000 cases each) in rural districts with low endemicity (<50 cases per annum). The availability of state and local surveillance resources, along and the availability of adjacent non-endemic districts to serve as control sites, has provided a unique opportunity to determine factors leading to (a) the epidemic establishment and (b) the domesticity of the transmission cycle. The project developed herein focuses on a district involved in an epidemic of >2,000 cases across 112 townships and has evolved the following specific aims: (1) To detect a human-to-sand fly-to-human mode of transmission. The normal sylvatic mode of transmission to humans is via a reservoir animal to sand fly. (2) To determine the roles of the common peridomestic animals?opossums, dogs and equines?as parasite reservoirs. (3) To incriminate the insect vector species. Four species are identified in the epidemic areas, but details of their density, vector competence and host preference are not characterized. (4) To examine the population genetic structure of a newly dominant vector species, Lutzomyia longiflocosa, for its genetic heterogeneity and ecological origins. (5) To model vector-reservoir-human relationships for optimization of control strategies. State of art field methods and analytic tools will be employed, including molecular genetic strategies (gene sequencing, SSCP gel sieving), geographical information systems (including local mapping with GPS and remotely sensed imagery), and iterative modeling.