Disease-driven reduction in human mobility influences human-mosquito contacts and dengue transmission dynamics

• Type of Material: Article
• Authors: Kathryn L. Schaber, Emory University; T. Alex Perkins, University of Notre Dame; Alun L. Lloyd, North Carolina State University; Lance Waller, Emory University; Uriel Kitron, Emory University; Valerie A. Paz-Soldan, Tulane University; John P. Elder, San Diego State University; Alan L. Rothman, University of Rhode Island; David Civitello, Emory University; William H. Elson, University of California Davis; Amy C. Morrison, University of California Davis; Thomas W. Scott, University of California Davis; Gonzalo M. Vazquez-Prokopec, Emory University
• Language: English
• Date: 2021-01-01
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: Author A.C.M. is a federal/contracted employee of the United States government. This work was prepared as part of her official duties. Title 17 U.S.C. §105 provides that ‘Copyright protection under this title is not available for any work of the United States Government.’ Title 17 U.S.C. §101 defines a U.S. Government work as a work prepared by a military service member or employee of the U.S. Government as part of that person’s official duties.
• License: Creative Commons Universal : Public Domain Dedication
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pcbi.1008627
• Title of Journal or Parent Work: PLoS Computational Biology
• Volume: 17
• Issue: 1
• Start Page: e1008627
• End Page: e1008627
• Grant/Funding Information: This research was supported by funding from the US National Institutes of Health-National Institute of Allergy and Infectious Diseases (NIH-NIAID) award number P01AI098670 (to T.W.S.).
• Keywords: Life Sciences & Biomedicine; Biochemical Research Methods; Population; Impact; Puerto Rico; People; Heterogeneity; Biochemistry & Molecular Biology; Mathematical & Computational Biology; Science & Technology
• Research Categories: Health Sciences, Public Health; Chemistry, Biochemistry; Computer Science; Mathematics

Abstract

Heterogeneous exposure to mosquitoes determines an individual’s contribution to vector-borne pathogen transmission. Particularly for dengue virus (DENV), there is a major difficulty in quantifying human-vector contacts due to the unknown coupled effect of key heterogeneities. To test the hypothesis that the reduction of human out-of-home mobility due to dengue illness will significantly influence population-level dynamics and the structure of DENV transmission chains, we extended an existing modeling framework to include social structure, disease-driven mobility reductions, and heterogeneous transmissibility from different infectious groups. Compared to a baseline model, naïve to human pre-symptomatic infectiousness and disease-driven mobility changes, a model including both parameters predicted an increase of 37% in the probability of a DENV outbreak occurring; a model including mobility change alone predicted a 15.5% increase compared to the baseline model. At the individual level, models including mobility change led to a reduction of the importance of out-of-home onward transmission (R, the fraction of secondary cases predicted to be generated by an individual) by symptomatic individuals (up to -62%) at the expense of an increase in the relevance of their home (up to +40%). An individual’s positive contribution to R could be predicted by a GAM including a non-linear interaction between an individual’s biting suitability and the number of mosquitoes in their home (>10 mosquitoes and 0.6 individual attractiveness significantly increased R). We conclude that the complex fabric of social relationships and differential behavioral response to dengue illness cause the fraction of symptomatic DENV infections to concentrate transmission in specific locations, whereas asymptomatic carriers (including individuals in their pre-symptomatic period) move the virus throughout the landscape. Our findings point to the difficulty of focusing vector control interventions reactively on the home of symptomatic individuals, as this approach will fail to contain virus propagation by visitors to their house and asymptomatic carriers.