Vector incrimination and entomological inoculation rates.

Abstract

This chapter provides standard methods for the incrimination of Anopheles mosquito species serving as malaria vectors and associated methods for measuring the intensity of transmission. In any malaria-endemic area, one or more species of Anopheles mosquitoes serve as malaria vectors. To show that an Anopheles mosquito species serves as a malaria vector in nature, it is necessary to demonstrate: 1. An association in time and space between the Anopheles species of mosquito and cases of malaria in humans. After study sites are selected, longitudinal field studies are established to sample mosquito populations. Adult mosquitoes are sampled by using trapping techniques such as landing/biting collections, light traps, pyrethrum spray catches inside houses, and outdoor aspiration collections. Larval mosquitoes developing in aquatic habitats normally are sampled by dipping methods. Mosquitoes are identified by standard taxonomic methods and also by molecular methods if mosquitoes belong to a species complex. The standard methods for performing landing/biting collections are described in this chapter; other types of mosquito trapping methods are described in refs. and . 2. Evidence of direct contact between the Anopheles species and humans. Catching a mosquito biting humans through landing/biting catches conclusively establishes contact between that mosquito species and humans. A second method involves immunologically identifying human blood in the abdomen of field-captured Anopheles mosquitoes. A direct enzyme-linked immunosorbent assay (ELISA) suitable for bloodmeal identification of African malaria vectors is described in this chapter (). 3. Evidence that the Anopheles species harbors malaria sporozoites in the salivary glands. Sporozoites may be detected in mosquitoes through the dissection and microscopic examination of mosquito salivary glands () or through ELISA methods (). Both methods are described in this chapter.