title: Outdoor biting by Anopheles mosquitoes on Bioko Island does not currently impact on malaria control.
abstract: BACKGROUND
  There have been many recent reports that the rate of outdoor biting by malaria vectors has increased. This study examined the impact this might have on malaria transmission by assessing the association between exposure to outdoor bites and malaria infection on Bioko Island, Equatorial Guinea.
  
  
  METHODS
  Responses to questions about time spent outside the previous night from a malaria indicator survey were combined with human landing catch measurements of hourly rates of outdoor and indoor biting for the whole island to estimate the number of outdoor and indoor bites received by each survey respondent. The association between RDT measured malaria infection status of individuals and outdoor bites received was investigated.
  
  
  RESULTS
  The average number of bites received per person per night was estimated as 3.51 in total, of which 0.69 (19.7%) would occur outdoors. Malaria infection was not significantly higher in individuals who reported spending time outside between 7 pm and 6 am the previous night compared to those not spending time outside in both adults (18.9% vs 17.4%, p = 0.20) and children (29.2% vs 27.1%, p = 0.20). Malaria infection in neither adults (p = 0.56) nor in children (p = 0.12) was associated with exposure to outdoor bites, even after adjusting for confounders.
  
  
  CONCLUSIONS
  Malaria vector mosquitoes in Bioko do bite humans outdoors, and this has the potential to reduce the effectiveness of vector control. However, outdoor biting is currently not a major factor influencing the malaria burden, mainly because more than 95% of the population are indoors during the middle of the night, which is the peak biting period for malaria vector mosquitoes. The majority of resources should remain with control measures that target indoor biting and resting such as LLINs and IRS.
authors.affiliation: MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK. john.bradley@lshtm.ac.uk.
authors.forename: John
authors.initials: J
authors.lastname: Bradley
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK. jo.lines@lshtm.ac.uk.
authors.forename: Jo
authors.initials: J
authors.lastname: Lines
authors.affiliation: Medical Care Development International, Malabo, Equatorial Guinea. gfuseini@mcd.org.
authors.forename: Godwin
authors.initials: G
authors.lastname: Fuseini
authors.affiliation: Medical Care Development International, Silver Spring, MD, USA. cschwabe@mcd.org.
authors.forename: Christopher
authors.initials: C
authors.lastname: Schwabe
authors.affiliation: Medical Care Development International, Malabo, Equatorial Guinea. felixmonti@gmail.com.
authors.forename: Feliciano
authors.initials: F
authors.lastname: Monti
authors.affiliation: Texas A & M University, College Station, TX, USA. maslotman@ag.tamu.edu.
authors.forename: Michel
authors.initials: M
authors.lastname: Slotman
authors.affiliation: Medical Care Development International, Malabo, Equatorial Guinea. vargasdany@yahoo.es.
authors.forename: Daniel
authors.initials: D
authors.lastname: Vargas
authors.affiliation: Medical Care Development International, Malabo, Equatorial Guinea. ggarcia@mcd.org.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Garcia
authors.affiliation: Medical Care Development International, Malabo, Equatorial Guinea. dhergott@mcd.org.
authors.forename: Dianna
authors.initials: D
authors.lastname: Hergott
authors.affiliation: MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK. immo.kleinschmidt@lshtm.ac.uk.|Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. immo.kleinschmidt@lshtm.ac.uk.
authors.forename: Immo
authors.initials: I
authors.lastname: Kleinschmidt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000852:Anopheles / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D016703:Equatorial Guinea / Q000453:epidemiology; D005247:Feeding Behavior; D005260:Female; D006802:Human Activities; D006801:Humans; D007223:Infant; D007299:Insect Bites and Stings / Q000453:epidemiology*; D062312:Islands / Q000453:epidemiology; D008288:Malaria / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission; D008297:Male; D008875:Middle Aged; D012306:Risk; D055815:Young Adult