Linking human behaviours and malaria vector biting risk in south-eastern Tanzania

Finda, M. F. et al. (2019) Linking human behaviours and malaria vector biting risk in south-eastern Tanzania. PLoS ONE, 14(6), e0217414. (doi: 10.1371/journal.pone.0217414) (PMID:31158255) (PMCID:PMC6546273)

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To accelerate malaria elimination in areas where core interventions such as insecticide-treated nets (ITNs) are already widely used, it is crucial to consider additional factors associated with persistent transmission. Qualitative data on human behaviours and perceptions regarding malaria risk was triangulated with quantitative data on Anopheles mosquito bites occurring indoors and outdoors in south-eastern Tanzania communities where ITNS are already used but lower level malaria transmission persists. Each night (18:00h-07:00h), trained residents recorded human activities indoors, in peri-domestic outdoor areas, and in communal gatherings. Host-seeking mosquitoes were repeatedly collected indoors and outdoors hourly, using miniaturized exposure-free double net traps (DN-Mini) occupied by volunteers. In-depth interviews were conducted with household representatives to explore perceptions on persistent malaria and its control. Higher proportions of people stayed outdoors than indoors in early-evening and early-morning hours, resulting in higher exposures outdoors than indoors during these times. However, exposure during late-night hours (22:00h–05:00h) occurred mostly indoors. Some of the popular activities that kept people outdoors included cooking, eating, relaxing and playing. All households had at least one bed net, and 83.9% of people had access to ITNs. Average ITN use was 96.3%, preventing most indoor exposure. Participants recorgnized the importance of ITNs but also noted that the nets were not perfect. No complementary interventions were reported being used widely. Most people believed transmission happens after midnight. We conclude that insecticide-treated nets, where properly used, can still prevent most indoor exposures, but significant risk continues unabated before bedtime, outdoors and at communal gatherings. Such exposure is greatest for rural and low-income households. There is therefore an urgent need for complementary interventions, particularly those targeting outdoor-biting and are applicable for all people including the marginalised populations such as migratory farmers and fishermen. Besides, the differences in community understanding of ongoing transmission, and feedback on imperfections of ITNs should be considered when updating malaria-related communication and interventions.

Item Type:Articles
Additional Information:This work was supported by the World Health Organization’s Tropical Disease Research (TDR) group [Ref: 2015/590235-0]. FO is also supported by a Wellcome Trust Intermediate Fellowship in Public Health and Tropical Medicine (Grant Number: WT102350/Z/13). LF and IM were also supported through a Consortium for Advanced Research Training (CARTA) grant awarded by Wellcome Trust (Grant No: 087547/Z/08/Z), the Carnegie Corporation of New York [B 8606.R02], and Sida [54100029].
Glasgow Author(s) Enlighten ID:Ngowo, Halfan and Okumu, Dr Fredros
Creator Roles:
Ngowo, H. S.Formal analysis, Writing – review and editing
Okumu, F. O.Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Resources, Software, Supervision, Validation, Visualization, Writing – review and editing
Authors: Finda, M. F., Moshi, I. R., Monroe, A., Limwagu, A. J., Nyoni, A. P., Swai, J. K., Ngowo, H. S., Minja, E. G., Toe, L. P., Kaindoa, E. W., Coetzee, M., Manderson, L., and Okumu, F. O.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN (Online):1932-6203
Copyright Holders:This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose
First Published:First published in PLoS ONE 14(6): e0217414
Publisher Policy:Reproduced under a Creative Commons License

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