title: Risk analysis of the re-emergence of Plasmodium vivax malaria in Japan using a stochastic transmission model.
abstract: OBJECTIVE
  This study analyzed the risk of infection with Plasmodium vivax in local residents through a stochastic simulation in which an infected tourist, local resident, or immigrants from an endemic area would visit Himi-shi, Toyama prefecture, which is a formerly endemic area in Japan.
  
  
  METHODS
  In Toyama, the habitats of Anopheles sinensis, which can transmit P. vivax, have been examined previously. We constructed a stochastic model of P. vivax transmission that can handle small numbers of infected persons and infected mosquitoes. The seasonal fluctuation in the numbers of captured An. sinensis was taken into account in the model.
  
  
  RESULTS
  Ten thousand trial simulations were carried out stochastically with a range of human blood indexes (HBI) of 1-10% for a range of months (June-September). The simulation results for a realistic assumption of a 1% HBI showed that the risk of infection for local residents was low (below 1%) except for the immigrants scenario.
  
  
  CONCLUSIONS
  The risk of infection among local residents (second cycle) was estimated to be very low for all situations. Therefore, there is little possibility for P. vivax infection to become established in this area of Japan.
authors: Department of Human Ecology, Graduate School of Environmental Science, Okayama University, Okayama, 700-8530, Japan.
authors: Tomoyuki
authors: T
authors: Bitoh
authors: Kaoru
authors: K
authors: Fueda
authors: Hiroshi
authors: H
authors: Ohmae
authors: Mamoru
authors: M
authors: Watanabe
authors: Hirofumi
authors: H
authors: Ishikawa
mesh_terms: D000818:Animals; D000852:Anopheles / Q000469:parasitology*; D003198:Computer Simulation; D054242:Emigrants and Immigrants; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology*; D007564:Japan / Q000453:epidemiology; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission*; D008954:Models, Biological; D010966:Plasmodium vivax / Q000502:physiology; D018570:Risk Assessment; D012621:Seasons; D013269:Stochastic Processes