Quantifying individual variability in exposure risk to mosquito bites in the Cascades region, Burkina Faso

Guglielmo, Federica, Sanou, Antoine, Churcher, Thomas S, Ranson, Hilary ORCID: https://orcid.org/0000-0003-2332-8247 and Sherrard-Smith, Ellie (2021) 'Quantifying individual variability in exposure risk to mosquito bites in the Cascades region, Burkina Faso'. Malaria Journal, Vol 20, Issue 44.

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Abstract

Background
The Cascades region, Burkina Faso, has a high malaria burden despite reported high insecticide-treated mosquito net (ITN) use. Human and vector activities outside the hours when indoor interventions offer direct protection from infectious bites potentially increase exposure risk to bites from malaria-transmitting Anopheles mosquitoes. This work investigated the degree of variation in human behaviour both between individuals and through time (season) to quantify how it impacts exposure to malaria vectors.

Methods
Patterns in human overnight activity (18:00–06:00) to quantify time spent using an ITN across 7 successive nights in two rural communities, Niakore (N = 24 participants) and Toma (71 participants), were observed in the dry and rainy seasons, between 2017 and 2018. Hourly human landing Anopheles mosquito catches were conducted in Niakore specifically, and Cascades region generally, between 2016 and 2017. Data were statistically combined to estimate seasonal variation in time spent outdoors and Anopheles bites received per person per night (bpppn).

Results
Substantial variability in exposure to outdoor Anopheles bites was detected within and between communities across seasons. In October, when Anopheles densities are highest, an individual’s risk of Anopheles bites ranged from 2.2 to 52.2 bites per person per night (bpppn) within the same week with variable risk dependent on hours spent indoors. Comparably higher outdoor human activity was observed in April and July but, due to lower Anopheles densities estimated, bpppn were 0.2–4.7 and 0.5–32.0, respectively. Males and people aged over 21 years were predicted to receive more bites in both sentinel villages.

Conclusion
This work presents one of the first clear descriptions of the degree of heterogeneity in time spent outdoors between people and across the year. Appreciation of sociodemographic, cultural and entomological activities will help refine approaches to vector control.

Item Type:	Article
Subjects:	QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes WA Public Health > Health Problems of Special Population Groups > WA 395 Health in developing countries WC Communicable Diseases > Tropical and Parasitic Diseases > WC 750 Malaria
Faculty: Department:	Biological Sciences > Vector Biology Department
Digital Object Identifer (DOI):	https://doi.org/10.1186/s12936-020-03538-5
Depositing User:	Mel Finley
Date Deposited:	25 Jan 2021 12:39
Last Modified:	25 Jan 2021 12:39
URI:	https://archive.lstmed.ac.uk/id/eprint/16332

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