Simplified Models of Vector Control Impact upon Malaria Transmission by Zoophagic Mosquitoes

Kiware, Samson S., Chitnis, Nakul, Moore, Sarah J., Devine, Gregor J., Majambere, Silas, Merrill, Stephen and Killeen, Gerry ORCID: https://orcid.org/0000-0002-8583-8739 (2012) 'Simplified Models of Vector Control Impact upon Malaria Transmission by Zoophagic Mosquitoes'. PLoS ONE, Vol 7, Issue 5, e37661.

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Abstract

Background

High coverage of personal protection measures that kill mosquitoes dramatically reduce malaria transmission where vector populations depend upon human blood. However, most primary malaria vectors outside of sub-Saharan Africa can be classified as “very zoophagic,” meaning they feed occasionally (<10% of blood meals) upon humans, so personal protection interventions have negligible impact upon their survival.

Methods and Findings

We extended a published malaria transmission model to examine the relationship between transmission, control, and the baseline proportion of bloodmeals obtained from humans (human blood index). The lower limit of the human blood index enables derivation of simplified models for zoophagic vectors that (1) Rely on only three field-measurable parameters. (2) Predict immediate and delayed (with and without assuming reduced human infectivity, respectively) impacts of personal protection measures upon transmission. (3) Illustrate how appreciable indirect communal-level protection for non-users can be accrued through direct personal protection of users. (4) Suggest the coverage and efficacy thresholds required to attain epidemiological impact. The findings suggest that immediate, indirect, community-wide protection of users and non-users alike may linearly relate to the efficacy of a user’s direct personal protection, regardless of whether that is achieved by killing or repelling mosquitoes. High protective coverage and efficacy (≥80%) are important to achieve epidemiologically meaningful impact. Non-users are indirectly protected because the two most common species of human malaria are strict anthroponoses. Therefore, the small proportion of mosquitoes that are killed or diverted while attacking humans can represent a large proportion of those actually transmitting malaria.

Conclusions

Simplified models of malaria transmission by very zoophagic vectors may be used by control practitioners to predict intervention impact interventions using three field-measurable parameters; the proportion of human exposure to mosquitoes occurring when an intervention can be practically used, its protective efficacy when used, and the proportion of people using it.

Item Type:	Article
Subjects:	QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases WC Communicable Diseases > Tropical and Parasitic Diseases > WC 750 Malaria WC Communicable Diseases > Tropical and Parasitic Diseases > WC 765 Prevention and control
Faculty: Department:	Groups (2002 - 2012) > Vector Group
Digital Object Identifer (DOI):	https://doi.org/10.1371/journal.pone.0037661
Depositing User:	Lynn Roberts-Maloney
Date Deposited:	16 Jan 2015 12:23
Last Modified:	16 Sep 2019 10:12
URI:	https://archive.lstmed.ac.uk/id/eprint/4769

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