title: Infectious reservoir of Plasmodium infection in Mae Hong Son Province, north-west Thailand.
abstract: BACKGROUND
  It was unknown whether the main reservoir of Plasmodium falciparum and Plasmodium vivax, which infects mosquitoes in Thailand, was (a) in people feeling sufficiently ill with malaria to come to a clinic or (b) in people who had remained in their home villages with some fever symptoms or with none.
  
  
  METHODS
  Mass surveys were carried out in Thai villages to identify people with Plasmodium infections and with fever. Malaria patients were also located at a clinic which served these villages. Adults from both sources whose blood slides registered positive for Plasmodium spp. were requested to allow laboratory-bred Anopheles minimus to feed on them. Seven to nine days after the blood feeds the mosquitoes were dissected and checked for presence of oocysts.
  
  
  CONCLUSIONS
  There were higher rates of Plasmodium infection among people in the villages with fever than without fever and much higher rates of infection among clinic patients than among people who had remained in the villages. People with malarial infections identified via the clinic and the village surveys could infect mosquitoes, especially, but not only, if their blood slides showed visible gametocytes. Because only a very small minority of the village populations were visiting the clinic on any one day, assessment indicated that the main reservoir of infection was not primarily among clinic patients but among those in the villages, especially those feeling feverish.
  
  
  CONCLUSIONS
  Efficient use of an anti-gametocyte drug to suppress the parasite reservoir in a population requires that it be given, not just to clinic patients, but to infected people located by mass surveys of the villages, especially those feeling feverish.
authors.affiliation: London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK. pethleart@yahoo.com
authors.forename: Aree
authors.initials: A
authors.lastname: Pethleart
authors.forename: Somsak
authors.initials: S
authors.lastname: Prajakwong
authors.forename: Wannapa
authors.initials: W
authors.lastname: Suwonkerd
authors.forename: Boontawee
authors.initials: B
authors.lastname: Corthong
authors.forename: Roger
authors.initials: R
authors.lastname: Webber
authors.forename: Christopher
authors.initials: C
authors.lastname: Curtis
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000818:Animals; D000852:Anopheles / Q000469:parasitology; D002648:Child; D004197:Disease Reservoirs / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology; D016778:Malaria, Falciparum / Q000453:epidemiology*; D016780:Malaria, Vivax / Q000453:epidemiology*; D018512:Parasitemia / Q000453:epidemiology; D015995:Prevalence; D013785:Thailand / Q000453:epidemiology