title: Plasticity of host selection by malaria vectors of Papua New Guinea.
abstract: Host selection is an important determinant of vectorial capacity because malaria transmission increases when mosquitoes feed more on humans than non-humans. Host selection also affects the outcome of long-lasting insecticidal nets (LLIN). Despite the recent nationwide implementation of LLIN-based malaria control program in Papua New Guinea (PNG), little is known about the host selection of the local Anopheles vectors. This study investigated the host selection of Anopheles vectors in PNG.
  
  
  
  Blood-engorged mosquitoes were sampled using the barrier screen method and blood meals analyzed for vertebrate host source with PCR-amplification of the mitochondrial cytochrome b gene. Abundance of common hosts was estimated in surveys. The test of homogeneity of proportions and the Manly resource selection ratio were used to determine if hosts were selected in proportion to their abundance.
  
  
  
  Two thousand four hundred and forty blood fed Anopheles females of seven species were sampled from five villages in Madang, PNG. Of 2,142 samples tested, 2,061 (96.2%) yielded a definitive host source; all were human, pig, or dog. Hosts were not selected in proportion to their abundance, but rather were under-selected or over-selected by the mosquitoes. Four species, Anopheles farauti (sensu stricto) (s.s.), Anopheles punctulatus (s.s.), Anopheles farauti no. 4 and Anopheles longirostris, over-selected humans in villages with low LLIN usage, but over-selected pigs in villages with high LLIN usage. Anopheles koliensis consistently over-selected humans despite high LLIN usage, and Anopheles bancroftii over-selected pigs.
  
  
  
  The plasticity of host selection of an Anopheles species depends on its opportunistic, anthropophilic or zoophilic behavior, and on the extent of host availability and LLIN usage where the mosquitoes forage for hosts. The high anthropophily of An. koliensis increases the likelihood of contacting the LLIN inside houses. This allows its population size to be reduced to levels insufficient to support transmission. In contrast, by feeding on alternative hosts the likelihood of the opportunistic species to contact LLIN is lower, making them difficult to control. By maintaining high population size, the proportion that feed on humans outdoors can sustain residual transmission despite high LLIN usage in the village.
authors.affiliation: Papua New Guinea Institute of Medical Research, Vector Borne Diseases Unit, Madang, 511, Madang, Papua New Guinea. kevenjoh@msu.edu.|Department of Microbiology and Molecular Genetics, Michigan State University, 48824, East Lansing, MI, USA. kevenjoh@msu.edu.
authors.forename: John B
authors.initials: JB
authors.lastname: Keven
authors.affiliation: Liverpool School of Tropical Medicine and Hygiene, Liverpool, UK.
authors.forename: Lisa
authors.initials: L
authors.lastname: Reimer
authors.affiliation: Papua New Guinea Institute of Medical Research, Vector Borne Diseases Unit, Madang, 511, Madang, Papua New Guinea.
authors.forename: Michelle
authors.initials: M
authors.lastname: Katusele
authors.affiliation: Papua New Guinea Institute of Medical Research, Vector Borne Diseases Unit, Madang, 511, Madang, Papua New Guinea.
authors.forename: Gussy
authors.initials: G
authors.lastname: Koimbu
authors.affiliation: Papua New Guinea Institute of Medical Research, Vector Borne Diseases Unit, Madang, 511, Madang, Papua New Guinea.|Department of Entomology, Michigan State University, 48824, East Lansing, MI, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Vinit
authors.affiliation: Papua New Guinea Institute of Medical Research, Vector Borne Diseases Unit, Madang, 511, Madang, Papua New Guinea.
authors.forename: Naomi
authors.initials: N
authors.lastname: Vincent
authors.affiliation: Liverpool School of Tropical Medicine and Hygiene, Liverpool, UK.
authors.forename: Edward
authors.initials: E
authors.lastname: Thomsen
authors.affiliation: School of Criminal Justice and Department of Integrative Biology, Michigan State University, 48824, East Lansing, MI, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Foran
authors.affiliation: Center for Global Health and Diseases, Case Western Reserve University, 44106, Cleveland, OH, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Zimmerman
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, 48824, East Lansing, MI, USA.|Department of Entomology, Michigan State University, 48824, East Lansing, MI, USA.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Walker
mesh_terms: D000818:Animals; D000852:Anopheles / Q000502:physiology*; D001769:Blood; D016172:DNA Fingerprinting; D005247:Feeding Behavior; D006801:Humans; D000072138:Mosquito Vectors / Q000502:physiology*; D010219:Papua New Guinea
keywords: Anopheles; Anthropophilic; Hosts; Malaria; Opportunistic; Selection; Species; Zoophilic