title: Species composition, seasonal occurrence, habitat preference and altitudinal distribution of malaria and other disease vectors in eastern Nepal.
abstract: BACKGROUND
  It is increasingly recognized that climate change can alter the geographical distribution of vector-borne diseases (VBDs) with shifts of disease vectors to higher altitudes and latitudes. In particular, an increasing risk of malaria and dengue fever epidemics in tropical highlands and temperate regions has been predicted in different climate change scenarios. The aim of this paper is to expand the current knowledge on the seasonal occurrence and altitudinal distribution of malaria and other disease vectors in eastern Nepal.
  
  
  METHODS
  Adult mosquitoes resting indoors and outdoors were collected using CDC light trap and aspirators with the support of flash light. Mosquito larvae were collected using locally constructed dippers. We assessed the local residents' perceptions of the distribution and occurrence of mosquitoes using key informant interview techniques. Generalized linear models were fitted to assess the effect of season, resting site and topography on the abundance of malaria vectors.
  
  
  RESULTS
  The known malaria vectors in Nepal, Anopheles fluviatilis, Anopheles annularis and Anopheles maculatus complex members were recorded from 70 to 1,820 m above sea level (asl). The vectors of chikungunya and dengue virus, Aedes aegypti and Aedes albopictus, the vector of lymphatic filariasis, Culex quinquefasciatus, and that of Japanese encephalitis, Culex tritaeniorhynchus, were found from 70 to 2,000 m asl in eastern Nepal. Larvae of Anopheles, Culex and Aedes species were recorded up to 2,310 m asl. Only season had a significant effect on the abundance of An. fluviatilis, season and resting site on the abundance of An. maculatus complex members, and season, resting site and topography on the abundance of An. annularis. The perceptions of people on mosquito occurrence are consistent with entomological findings.
  
  
  CONCLUSIONS
  This study provides the first vertical distribution records of vector mosquitoes in eastern Nepal and suggests that the vectors of malaria and other diseases have already established populations in the highlands due to climatic and other environmental changes. As VBD control programmes have not been focused on the highlands of Nepal, these findings call for actions to start monitoring, surveillance and research on VBDs in these previously disease-free, densely populated and economically important regions.
authors.affiliation: Nepal Health Research Council (NHRC), Ministry of Health and Population Complex, Ramshah Path, Kathmandu, Nepal. meghdhimal@gmail.com.|Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung, Frankfurt am, Germany. meghdhimal@gmail.com.|Institute for Atmospheric and Environmental Sciences (IAU), Goethe University, Frankfurt am Main, Germany. meghdhimal@gmail.com.|Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Frankfurt am Main, Germany. meghdhimal@gmail.com.
authors.forename: Meghnath
authors.initials: M
authors.lastname: Dhimal
authors.affiliation: Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung, Frankfurt am, Germany. Bodo.Ahrens@iau.uni-frankfurt.de.|Institute for Atmospheric and Environmental Sciences (IAU), Goethe University, Frankfurt am Main, Germany. Bodo.Ahrens@iau.uni-frankfurt.de.
authors.forename: Bodo
authors.initials: B
authors.lastname: Ahrens
authors.affiliation: Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Frankfurt am Main, Germany. kuch@med.uni-frankfurt.de.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kuch
mesh_terms: D000531:Altitude; D063147:Animal Distribution / Q000502:physiology*; D000818:Animals; D057231:Climate Change; D009033:Culicidae / Q000502:physiology*; D017753:Ecosystem; D006801:Humans; D007303:Insect Vectors / Q000502:physiology*; D008288:Malaria / Q000453:epidemiology / Q000635:transmission*; D009390:Nepal / Q000453:epidemiology; D012621:Seasons; D013045:Species Specificity