Cargando…
Variations in household microclimate affect outdoor-biting behaviour of malaria vectors
Background: Mosquito behaviours including the degree to which they bite inside houses or outside is a crucial determinant of human exposure to malaria. Whilst seasonality in mosquito vector abundance is well documented, much less is known about the impact of climate on mosquito behaviour. We investi...
Autores principales: | , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
F1000 Research Limited
2017
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5829465/ https://www.ncbi.nlm.nih.gov/pubmed/29552642 http://dx.doi.org/10.12688/wellcomeopenres.12928.1 |
_version_ | 1783302814029578240 |
---|---|
author | Ngowo, Halfan S. Kaindoa, Emmanuel Wilson Matthiopoulos, Jason Ferguson, Heather M. Okumu, Fredros O. |
author_facet | Ngowo, Halfan S. Kaindoa, Emmanuel Wilson Matthiopoulos, Jason Ferguson, Heather M. Okumu, Fredros O. |
author_sort | Ngowo, Halfan S. |
collection | PubMed |
description | Background: Mosquito behaviours including the degree to which they bite inside houses or outside is a crucial determinant of human exposure to malaria. Whilst seasonality in mosquito vector abundance is well documented, much less is known about the impact of climate on mosquito behaviour. We investigated how variations in household microclimate affect outdoor-biting by malaria vectors, Anopheles arabiensis and Anopheles funestus. Methods: Mosquitoes were sampled indoors and outdoors weekly using human landing catches at eight households in four villages in south-eastern Tanzania, resulting in 616 trap-nights over 12 months. Daily temperature, relative humidity and rainfall were recorded. Generalized additive mixed models (GAMMs) were used to test associations between mosquito abundance and the microclimatic conditions. Generalized linear mixed models (GLMMs) were used to investigate the influence of microclimatic conditions on the tendency of vectors to bite outdoors (proportion of outdoor biting). Results: An. arabiensis abundance peaked during high rainfall months (February-May), whilst An. funestus density remained stable into the dry season (May-August) . Across the range of observed household temperatures, a rise of 1 (º)C marginally increased nightly An. arabiensis abundance (~11%), but more prominently increased An. funestus abundance (~66%). The abundance of An. arabiensis and An. funestus showed strong positive associations with time-lagged rainfall (2-3 and 3-4 weeks before sampling). The degree of outdoor biting in An. arabiensis was significantly associated with the relative temperature difference between indoor and outdoor environments, with exophily increasing as temperature inside houses became relatively warmer. The exophily of An. funestus did not vary with temperature differences. Conclusions: This study demonstrates that malaria vector An. arabiensis shifts the location of its biting from indoors to outdoors in association with relative differences in microclimatic conditions. These environmental impacts could give rise to seasonal variation in mosquito biting behaviour and degree of protection provided by indoor-based vector control strategies. |
format | Online Article Text |
id | pubmed-5829465 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | F1000 Research Limited |
record_format | MEDLINE/PubMed |
spelling | pubmed-58294652018-03-16 Variations in household microclimate affect outdoor-biting behaviour of malaria vectors Ngowo, Halfan S. Kaindoa, Emmanuel Wilson Matthiopoulos, Jason Ferguson, Heather M. Okumu, Fredros O. Wellcome Open Res Research Article Background: Mosquito behaviours including the degree to which they bite inside houses or outside is a crucial determinant of human exposure to malaria. Whilst seasonality in mosquito vector abundance is well documented, much less is known about the impact of climate on mosquito behaviour. We investigated how variations in household microclimate affect outdoor-biting by malaria vectors, Anopheles arabiensis and Anopheles funestus. Methods: Mosquitoes were sampled indoors and outdoors weekly using human landing catches at eight households in four villages in south-eastern Tanzania, resulting in 616 trap-nights over 12 months. Daily temperature, relative humidity and rainfall were recorded. Generalized additive mixed models (GAMMs) were used to test associations between mosquito abundance and the microclimatic conditions. Generalized linear mixed models (GLMMs) were used to investigate the influence of microclimatic conditions on the tendency of vectors to bite outdoors (proportion of outdoor biting). Results: An. arabiensis abundance peaked during high rainfall months (February-May), whilst An. funestus density remained stable into the dry season (May-August) . Across the range of observed household temperatures, a rise of 1 (º)C marginally increased nightly An. arabiensis abundance (~11%), but more prominently increased An. funestus abundance (~66%). The abundance of An. arabiensis and An. funestus showed strong positive associations with time-lagged rainfall (2-3 and 3-4 weeks before sampling). The degree of outdoor biting in An. arabiensis was significantly associated with the relative temperature difference between indoor and outdoor environments, with exophily increasing as temperature inside houses became relatively warmer. The exophily of An. funestus did not vary with temperature differences. Conclusions: This study demonstrates that malaria vector An. arabiensis shifts the location of its biting from indoors to outdoors in association with relative differences in microclimatic conditions. These environmental impacts could give rise to seasonal variation in mosquito biting behaviour and degree of protection provided by indoor-based vector control strategies. F1000 Research Limited 2017-10-24 /pmc/articles/PMC5829465/ /pubmed/29552642 http://dx.doi.org/10.12688/wellcomeopenres.12928.1 Text en Copyright: © 2017 Ngowo HS et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Article Ngowo, Halfan S. Kaindoa, Emmanuel Wilson Matthiopoulos, Jason Ferguson, Heather M. Okumu, Fredros O. Variations in household microclimate affect outdoor-biting behaviour of malaria vectors |
title | Variations in household microclimate affect outdoor-biting behaviour of malaria vectors |
title_full | Variations in household microclimate affect outdoor-biting behaviour of malaria vectors |
title_fullStr | Variations in household microclimate affect outdoor-biting behaviour of malaria vectors |
title_full_unstemmed | Variations in household microclimate affect outdoor-biting behaviour of malaria vectors |
title_short | Variations in household microclimate affect outdoor-biting behaviour of malaria vectors |
title_sort | variations in household microclimate affect outdoor-biting behaviour of malaria vectors |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5829465/ https://www.ncbi.nlm.nih.gov/pubmed/29552642 http://dx.doi.org/10.12688/wellcomeopenres.12928.1 |
work_keys_str_mv | AT ngowohalfans variationsinhouseholdmicroclimateaffectoutdoorbitingbehaviourofmalariavectors AT kaindoaemmanuelwilson variationsinhouseholdmicroclimateaffectoutdoorbitingbehaviourofmalariavectors AT matthiopoulosjason variationsinhouseholdmicroclimateaffectoutdoorbitingbehaviourofmalariavectors AT fergusonheatherm variationsinhouseholdmicroclimateaffectoutdoorbitingbehaviourofmalariavectors AT okumufredroso variationsinhouseholdmicroclimateaffectoutdoorbitingbehaviourofmalariavectors |