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Title: Temperature impacts the environmental suitability for malaria transmission by Anopheles gambiae and Anopheles stephensi
Abstract

Extrinsic environmental factors influence the spatiotemporal dynamics of many organisms, including insects that transmit the pathogens responsible for vector‐borne diseases (VBDs). Temperature is an especially important constraint on the fitness of a wide variety of ectothermic insects. A mechanistic understanding of how temperature impacts traits of ectotherms, and thus the distribution of ectotherms and vector‐borne infections, is key to predicting the consequences of climate change on transmission of VBDs like malaria. However, the response of transmission to temperature and other drivers is complex, as thermal traits of ectotherms are typically nonlinear, and they interact to determine transmission constraints. In this study, we assess and compare the effect of temperature on the transmission of two malaria parasites,Plasmodium falciparumandPlasmodium vivax, by two malaria vector species,Anopheles gambiaeandAnopheles stephensi. We model the nonlinear responses of temperature dependent mosquito and parasite traits (mosquito development rate, bite rate, fecundity, proportion of eggs surviving to adulthood, vector competence, mortality rate, and parasite development rate) and incorporate these traits into a suitability metric based on a model for the basic reproductive number across temperatures. Our model predicts that the optimum temperature for transmission suitability is similar for the four mosquito–parasite combinations assessed in this study, but may differ at the thermal limits. More specifically, we found significant differences in the upper thermal limit between parasites spread by the same mosquito (A. stephensi) and between mosquitoes carryingP. falciparum. In contrast, at the lower thermal limit the significant differences were primarily between the mosquito species that both carried the same pathogen (e.g.,A. stephensiandA. gambiaeboth withP. falciparum). Using prevalence data, we show that the transmission suitability metric calculated from our mechanistic model is consistent with observedP. falciparumprevalence in Africa and Asia but is equivocal forP. vivaxprevalence in Asia, and inconsistent withP. vivaxprevalence in Africa. We mapped risk to illustrate the number of months various areas in Africa and Asia predicted to be suitable for malaria transmission based on this suitability metric. This mapping provides spatially explicit predictions for suitability and transmission risk.

 
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Award ID(s):
1750113
NSF-PAR ID:
10444477
Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Ecology
Volume:
103
Issue:
8
ISSN:
0012-9658
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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