title: Factors affecting the propensity of tsetse flies to enter houses and attack humans inside: increased risk of sleeping sickness in warmer climates.
abstract: BACKGROUND
  Sleeping sickness, or human African trypanosomiasis, is caused by two species of Trypanosoma brucei that are transmitted to humans by tsetse flies (Glossina spp.) when these insects take a bloodmeal. It is commonly assumed that humans must enter the normal woodland habitat of the flies to become infected, but recent studies found that tsetse frequently attack humans inside buildings. Factors affecting human/tsetse contact in buildings need identification.
  
  
  RESULTS
  In Zimbabwe, tsetse were allowed access to a house via an open door. Those in the house at sunset, and those alighting on humans in the house during the day, were caught using hand-nets. Total catches were unaffected by: (i) the presence of humans in the house and at the door, (ii) wood smoke from a fire inside the house or just outside, (iii) open windows, and (iv) chemicals simulating the odor of cattle or of humans. Catches increased about 10-fold with rising ambient temperatures, and during the hottest months the proportion of the total catch that was taken from the humans increased from 5% to 13%. Of the tsetse caught from humans, 62% consisted of female G. morsitans morstans and both sexes of G. pallidipes, i.e., the group of tsetse that normally alight little on humans. Some of the tsetse caught were old enough to be effective vectors.
  
  
  CONCLUSIONS
  Present results confirm previous suggestions that buildings provide a distinctive and important venue for transmission of sleeping sickness, especially since the normal repellence of humans and smoke seems poorly effective in such places. The importance of the venue would be increased in warmer climates.
authors: Natural Resources Institute, University of Greenwich, Chatham, UK. valeglyn@gmail.com
authors: Glyn A
authors: GA
authors: Vale
authors: John W
authors: JW
authors: Hargrove
authors: Andrew
authors: A
authors: Chamisa
authors: David R
authors: DR
authors: Hall
authors: Clement
authors: C
authors: Mangwiro
authors: Stephen J
authors: SJ
authors: Torr
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D008297:Male; D012307:Risk Factors; D014346:Trypanosoma brucei brucei / Q000472:pathogenicity*; D014353:Trypanosomiasis, African / Q000453:epidemiology / Q000635:transmission*; D014370:Tsetse Flies / Q000469:parasitology*; D015030:Zimbabwe / Q000453:epidemiology
references: PLoS Negl Trop Dis. 2013;7(2):e2086
references: 23469309
references: Bull Entomol Res. 1946 Sep;37(2):291-9
references: 21000966
references: Trop Med Int Health. 2005 Sep;10(9):840-9
references: 16135190
references: PLoS Negl Trop Dis. 2012;6(8):e1791
references: 22953013
references: Parasitology. 1995 Aug;111 ( Pt 2):187-91
references: 7675533
references: PLoS Negl Trop Dis. 2012;6(12):e1978
references: 23301107