Time to Infection With Malaria Parasites
Condition: Plasmodium Falciparum Malaria
MeSH terms: Malaria; Malaria, Falciparum
Study type: Observational

Summary: 
      This study will attempt to find out what effect mosquito insecticides have on the
      transmission of malaria in The Gambia. Eight hundred healthy men and women, aged 18 to 40
      years, living in selected villages east of Farafenni town in The Gambia, West Africa will be
      screened for parasites. About 552 of these people are expected to be free of malaria and will
      form the study group. These people will participate in the study for 7 months and will be
      checked for the malaria-causing parasite every two weeks by finger prick blood sample.
    

Detailed description: 
      Malaria remains one of the world's greatest childhood killers and is a substantial obstacle
      to social and economic development in the tropics. The overwhelming bulk of the world's
      malaria burden rests upon the population of sub-Saharan Africa because of the unique
      coincidence of expanding human populations, weak health systems, the world's most effective
      vector mosquito species and environmental conditions ideal for transmission. At the start of
      the new millennium malaria is still deeply entrenched in Africa and effective malaria control
      is under threat from the inexorable spread of parasite strains resistant to antimalarial
      drugs and the emergence of mosquitoes resistant to the pyrethroid insecticides used to
      impregnate bednets. Larval control may offer a new alternative for effective control.
      Mosquito larval control strategies (environmental management and larviciding) have
      historically been shown to be successful in reducing the abundance of mosquitoes. This study
      plans to apply a larvicide in an effort to control malaria and reduce the burden of malaria.
      While it is abundantly clear that this product will kill mosquito larvae in the laboratory
      and in the field, it is not certain that doing so will reduce the burden of malaria for the
      human population. Briefly, the steps involved include survival and development of immature
      mosquito stages, emergence of adult mosquitoes, blood feeding by those mosquitoes,
      acquisition and development of malaria parasites by adult mosquitoes and transmission of
      parasites to susceptible humans. The objective of this pilot study is to evaluate the use of
      the time-to-infection end point as a measure of malaria transmission in The Gambia, while
      mosquito larvicides are used to control malaria vectors. The main outcomes of this study are
      (1) the proportion of adults with detectable parasitemia (Plasmodium falciparum) that is a
      binary variable and (2) time-to-infection with malaria parasites that will be treated as a
      continuous variable. This experimental design takes place over 7 months. The target sample
      size is 800 adults (aged 18-40 years, approximately half will be women and half men) living
      in 50 villages east of Farafenni town in The Gambia, West Africa. It is estimated that 552 of
      the adults will have no detectable parasites in their blood at the beginning of the
      transmission season (June). These parasite negative individuals will be followed either for
      the duration of the transmission season (June through November) or until they become positive
      for parasites.
    

Time perspective: Prospective
Keywords: malaria, Plasmodium falciparum, Gambia, larvicides, vector