title: Comparison of two adult mosquito sampling methods with human landing catches in south-central Ethiopia.
abstract: The human landing catch (HLC) is the standard reference method for measuring human exposure to mosquito bites. However, HLC is labour-intensive, exposes collectors to infectious mosquito bites and is subjected to collector bias. These necessitate local calibration and application of alternative methods. This study was undertaken to determine the relative sampling efficiency (RSE) of light traps with or without yeast-produced carbon dioxide bait vs. HLC in south-central Ethiopia.
  
  
  
  The experiment was conducted for 39 nights in a 3 × 3 Latin square randomized design with Anopheles arabiensis as the target species in the period between July and November 2014 in Edo Kontola village, south-central Ethiopia. Center for Disease Control and Prevention light trap catches (LTC) and yeast-generated carbon dioxide-baited light trap catches (CB-LTC) were each evaluated against HLC. The total nightly mosquito catches for each Anopheles species in either method was compared with HLC by Pearson correlation and simple linear regression analysis on log-transformed [log10(x + 1)] values. To test if the RSE of each alternative method was affected by mosquito density, the ratio of the number of mosquitoes in each method to the number of mosquitoes in HLC was plotted against the average mosquito abundance.
  
  
  
  Overall, 7606 Anopheles females were collected by the three sampling methods. Among these 5228 (68.7%) were Anopheles ziemanni, 1153 (15.2%) An. arabiensis, 883 (11.6%) Anopheles funestus s.l., and 342 (4.5%) Anopheles pharoensis. HLC yielded 3392 (44.6%), CB-LTC 2150 (28.3%), and LTC 2064 (27.1%) Anopheles females. The RSEs of LTC and HLC for An. arabiensis were significantly correlated (p < 0.001) and density independent (p = 0.65). However, for outdoor collection of the same species, RSEs of LTC and CB-LTC were density dependent (p < 0.001). It was estimated that on average, indoor LTC and CB-LTC each caught 0.35 and 0.44 times that of indoor HLC for An. arabiensis respectively.
  
  
  
  Results showed that HLC was the most efficient method for sampling An. arabiensis. LTC can be used for large-scale indoor An. arabiensis surveillance and monitoring when it is difficult to use HLC. CB-LTC does not substantially improve sampling of this major vector compared to LTC in this setting. Trial registration PACTR201411000882128 (retrospectively registered 8 September, 2014).
authors.affiliation: Department of Zoological Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia. qabanef2015@gmail.com.|Department of Biology, Wollega University, P. O. Box 395, Nekemte, Ethiopia. qabanef2015@gmail.com.
authors.forename: Oljira
authors.initials: O
authors.lastname: Kenea
authors.affiliation: Akililu Lemma Institute of Pathobiology, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Meshesha
authors.initials: M
authors.lastname: Balkew
authors.affiliation: Department of Zoological Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Habte
authors.initials: H
authors.lastname: Tekie
authors.affiliation: Akililu Lemma Institute of Pathobiology, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Teshome
authors.initials: T
authors.lastname: Gebre-Michael
authors.affiliation: Department of Preventive Medicine, School of Public Health, College of Health Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Wakgari
authors.initials: W
authors.lastname: Deressa
authors.affiliation: School of Public and Environmental Health, Hawassa University, P. O. Box 1560, Hawassa, Ethiopia.
authors.forename: Eskindir
authors.initials: E
authors.lastname: Loha
authors.affiliation: Centre for International Health, University of Bergen, P. O. Box 7804, 5020, Bergen, Norway.
authors.forename: Bernt
authors.initials: B
authors.lastname: Lindtjørn
authors.affiliation: Norwegian University of Life Sciences, P. O. Box 5003, 1432, Ås, Norway.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Overgaard
mesh_terms: D000328:Adult; D000818:Animals; D000852:Anopheles / Q000502:physiology*; D004772:Entomology / Q000379:methods*; D005002:Ethiopia; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007299:Insect Bites and Stings; D014838:Volunteers; D055815:Young Adult
keywords: Anopheles arabiensis; Ethiopia; Human landing catches; Light traps