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How house design affects malaria mosquito density, temperature, and relative humidity: an experimental study in rural Gambia.
Lancet Planet Health. 2018 11; 2(11):e498-e508.LP

Abstract

INTRODUCTION

Unprecedented improvements in housing are occurring across much of rural sub-Saharan Africa, but the consequences of these changes on malaria transmission remain poorly explored. We examined how different typologies of rural housing affect mosquito house entry and indoor climate.

METHODS

Five typologies of mud-block houses were constructed in rural Gambia: four were traditional designs with poorly fitted doors and one was a novel design with gable windows to improve ventilation. In each house, one male volunteer slept under a bednet and mosquitoes were collected indoors with a light trap. Typologies were rotated between houses weekly. Indoor conditions were monitored with data loggers and the perceived comfort of sleepers recorded with questionnaires. We used pyschrometric modelling to quantify the comfort of the indoor climate using the logger data. Primary measurements were mean number of Anopheles gambiae and mean temperature for each house typology.

FINDINGS

In thatched-roofed houses, closing the eaves reduced A gambiae house entry by 94% (95% CI 89-97) but increased the temperature compared with thatched-roofed houses with open eaves. In houses with closed eaves, those with metal roofs had more A gambiae, were hotter (1·5°C hotter [95% CI 1·3-1·7]) between 2100h and 2300 h, and had 25% higher concentrations of carbon dioxide (211·1 ppm higher [117·8-304·6]) than those with thatched roofs. In metal-roofed houses with closed eaves, mosquito house entry was reduced by 96% (91-98) by well fitted screened doors. Improved ventilation of metal-roofed houses made them as cool as thatched houses with open eaves. Metal-roofed houses with closed eaves were considered more uncomfortable than thatched ones with closed eaves. In metal-roofed houses, ventilated houses were more comfortable than unventilated houses before midnight, when people retired to bed.

INTERPRETATION

Closing the eaves reduced vector entry in thatched houses but increased entry in metal-roofed houses. Metal-roofed houses with closed eaves were, however, protected against malaria vectors by well fitted screened doors and were made comfortable by increasing ventilation. House designs that exclude mosquitoes and are comfortable to live in should be a priority in sub-Saharan Africa.

FUNDING

Sir Halley Stewart Trust, Global Clinical Trials, and Global Challenges Research Fund.

Authors+Show Affiliations

National Malaria Control Programme, Banjul, The Gambia.Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia.Tropical Epidemiology Group and Infectious Diseases Department, London School of Hygiene & Tropical Medicine, London, UK.Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia.National Malaria Control Programme, Banjul, The Gambia.The Royal Danish Academy of Fine Arts, Schools of Architecture, Design and Conservation, Copenhagen, Denmark.Department of Biosciences, Durham University, Durham, UK.Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia; Department of Biosciences, Durham University, Durham, UK.Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia; Tropical Epidemiology Group and Infectious Diseases Department, London School of Hygiene & Tropical Medicine, London, UK.Department of Biosciences, Durham University, Durham, UK; Tropical Epidemiology Group and Infectious Diseases Department, London School of Hygiene & Tropical Medicine, London, UK. Electronic address: s.w.lindsay@durham.ac.uk.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30396441

Citation

Jatta, Ebrima, et al. "How House Design Affects Malaria Mosquito Density, Temperature, and Relative Humidity: an Experimental Study in Rural Gambia." The Lancet. Planetary Health, vol. 2, no. 11, 2018, pp. e498-e508.
Jatta E, Jawara M, Bradley J, et al. How house design affects malaria mosquito density, temperature, and relative humidity: an experimental study in rural Gambia. Lancet Planet Health. 2018;2(11):e498-e508.
Jatta, E., Jawara, M., Bradley, J., Jeffries, D., Kandeh, B., Knudsen, J. B., Wilson, A. L., Pinder, M., D'Alessandro, U., & Lindsay, S. W. (2018). How house design affects malaria mosquito density, temperature, and relative humidity: an experimental study in rural Gambia. The Lancet. Planetary Health, 2(11), e498-e508. https://doi.org/10.1016/S2542-5196(18)30234-1
Jatta E, et al. How House Design Affects Malaria Mosquito Density, Temperature, and Relative Humidity: an Experimental Study in Rural Gambia. Lancet Planet Health. 2018;2(11):e498-e508. PubMed PMID: 30396441.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - How house design affects malaria mosquito density, temperature, and relative humidity: an experimental study in rural Gambia. AU - Jatta,Ebrima, AU - Jawara,Musa, AU - Bradley,John, AU - Jeffries,David, AU - Kandeh,Balla, AU - Knudsen,Jakob B, AU - Wilson,Anne L, AU - Pinder,Margaret, AU - D'Alessandro,Umberto, AU - Lindsay,Steve W, PY - 2018/05/11/received PY - 2018/09/27/revised PY - 2018/10/12/accepted PY - 2018/11/7/entrez PY - 2018/11/7/pubmed PY - 2019/8/28/medline SP - e498 EP - e508 JF - The Lancet. Planetary health JO - Lancet Planet Health VL - 2 IS - 11 N2 - INTRODUCTION: Unprecedented improvements in housing are occurring across much of rural sub-Saharan Africa, but the consequences of these changes on malaria transmission remain poorly explored. We examined how different typologies of rural housing affect mosquito house entry and indoor climate. METHODS: Five typologies of mud-block houses were constructed in rural Gambia: four were traditional designs with poorly fitted doors and one was a novel design with gable windows to improve ventilation. In each house, one male volunteer slept under a bednet and mosquitoes were collected indoors with a light trap. Typologies were rotated between houses weekly. Indoor conditions were monitored with data loggers and the perceived comfort of sleepers recorded with questionnaires. We used pyschrometric modelling to quantify the comfort of the indoor climate using the logger data. Primary measurements were mean number of Anopheles gambiae and mean temperature for each house typology. FINDINGS: In thatched-roofed houses, closing the eaves reduced A gambiae house entry by 94% (95% CI 89-97) but increased the temperature compared with thatched-roofed houses with open eaves. In houses with closed eaves, those with metal roofs had more A gambiae, were hotter (1·5°C hotter [95% CI 1·3-1·7]) between 2100h and 2300 h, and had 25% higher concentrations of carbon dioxide (211·1 ppm higher [117·8-304·6]) than those with thatched roofs. In metal-roofed houses with closed eaves, mosquito house entry was reduced by 96% (91-98) by well fitted screened doors. Improved ventilation of metal-roofed houses made them as cool as thatched houses with open eaves. Metal-roofed houses with closed eaves were considered more uncomfortable than thatched ones with closed eaves. In metal-roofed houses, ventilated houses were more comfortable than unventilated houses before midnight, when people retired to bed. INTERPRETATION: Closing the eaves reduced vector entry in thatched houses but increased entry in metal-roofed houses. Metal-roofed houses with closed eaves were, however, protected against malaria vectors by well fitted screened doors and were made comfortable by increasing ventilation. House designs that exclude mosquitoes and are comfortable to live in should be a priority in sub-Saharan Africa. FUNDING: Sir Halley Stewart Trust, Global Clinical Trials, and Global Challenges Research Fund. SN - 2542-5196 UR - https://www.unboundmedicine.com/medline/citation/30396441/How_house_design_affects_malaria_mosquito_density_temperature_and_relative_humidity:_an_experimental_study_in_rural_Gambia_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S2542-5196(18)30234-1 DB - PRIME DP - Unbound Medicine ER -