Time-varying, serotype-specific force of infection of dengue virus.
Infectious disease models play a key role in public health planning. These models rely on accurate estimates of key transmission parameters such as the force of infection (FoI), which is the per-capita risk of a susceptible person being infected. The FoI captures the fundamental dynamics of transmission and is crucial for gauging control efforts, such as identifying vaccination targets. Dengue virus (DENV) is a mosquito-borne, multiserotype pathogen that currently infects ∼390 million people a year. Existing estimates of the DENV FoI are inaccurate because they rely on the unrealistic assumption that risk is constant over time. Dengue models are thus unreliable for designing vaccine deployment strategies. Here, we present to our knowledge the first time-varying (daily), serotype-specific estimates of DENV FoIs using a spline-based fitting procedure designed to examine a 12-y, longitudinal DENV serological dataset from Iquitos, Peru (11,703 individuals, 38,416 samples, and 22,301 serotype-specific DENV infections from 1999 to 2010). The yearly DENV FoI varied markedly across time and serotypes (0-0.33), as did daily basic reproductive numbers (0.49-4.72). During specific time periods, the FoI fluctuations correlated across serotypes, indicating that different DENV serotypes shared common transmission drivers. The marked variation in transmission intensity that we detected indicates that intervention targets based on one-time estimates of the FoI could underestimate the level of effort needed to prevent disease. Our description of dengue virus transmission dynamics is unprecedented in detail, providing a basis for understanding the persistence of this rapidly emerging pathogen and improving disease prevention programs.
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Department of Entomology and Nematology, University of California, Davis, CA 95616; rcreiner@ucdavis.edu.
Robert C
RC
Reiner
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Department of Entomology and Nematology, University of California, Davis, CA 95616;
Steven T
ST
Stoddard
US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Brett M
BM
Forshey
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109;
Aaron A
AA
King
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT 05405;
Alicia M
AM
Ellis
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Department of Mathematics and Biomathematics Graduate Program, North Carolina State University, Raleigh, NC 27695;
Alun L
AL
Lloyd
Department of Entomology and Nematology, University of California, Davis, CA 95616;Department of Biology, Andrews University, Berrien Springs, MI 49104;
Kanya C
KC
Long
US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Claudio
C
Rocha
US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Stalin
S
Vilcarromero
US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Helvio
H
Astete
US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Isabel
I
Bazan
Liverpool School of Tropical Medicine, Liverpool, Merseyside L3 5QA, United Kingdom;Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333;
Audrey
A
Lenhart
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Department of Environmental Sciences, Emory University, Atlanta, GA 30322;
Gonzalo M
GM
Vazquez-Prokopec
Global Health Systems and Development, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112; and.
Valerie A
VA
Paz-Soldan
Liverpool School of Tropical Medicine, Liverpool, Merseyside L3 5QA, United Kingdom;
Philip J
PJ
McCall
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Department of Environmental Sciences, Emory University, Atlanta, GA 30322;
Uriel
U
Kitron
Institute for Behavioral and Community Health, Graduate School of Public Health, San Diego State University, San Diego, CA 92182.
John P
JP
Elder
US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Eric S
ES
Halsey
Department of Entomology and Nematology, University of California, Davis, CA 95616;US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Amy C
AC
Morrison
US Naval Medical Research Unit No. 6 Lima and Iquitos, Peru;
Tadeusz J
TJ
Kochel
Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;Department of Entomology and Nematology, University of California, Davis, CA 95616;
Thomas W
TW
Scott
D003715:Dengue / Q000453:epidemiology* / Q000635:transmission*; D003716:Dengue Virus / Q000235:genetics*; D006801:Humans; D008137:Longitudinal Studies; D008954:Models, Biological; D010568:Peru / Q000453:epidemiology; D062486:Public Health Surveillance / Q000379:methods*; D013997:Time Factors
arthropod-borne virus; disease ecology; emerging infections