- Author: Kathy Keatley Garvey
(News embargo lifts at noon Monday, May 19, 2014, Pacific Time)
Listen to Video, Robert Reiner (YouTube, Created by Professor James Carey)
DAVIS--Newly published research involving a 12-year study of dengue infections in Iquitos, Peru—an international team project led by researchers at the University of California, Davis—helps explain why interventions are frequently unsuccessful in efforts to prevent the mosquito-borne disease.
"Defining variation in the risk of dengue transmission has been a roadblock to understanding disease dynamics and designing more realistic and effective disease prevention programs,” said Scott, noted dengue researcher and a senior author of the paper, “Time-Varying, Serotype-Specific Force of Infection of Dengue Virus.”
“This study is an important step toward overcoming that obstacle,” Scott said. “We hope our results will help reduce the burden of this increasingly devastating disease."
“Typically, most infections go unnoticed and as such, measuring and modeling transmission intensity is problematic,” Reiner said.
Dengue virus is transmitted by Aedes aegypti, a mosquito that bites during the daytime as people move about in their daily routines.
“Our work suggests that certain serotypes can infect up to 33 percent of the susceptible population in a single year and that 79 percent of the population of Iquitos would need to be protected from any further infection to eliminate transmission. Further, our estimates form a detailed description of virus transmission dynamics that provides a basis for understanding the long-term persistence of dengue and for improving disease prevention programs.”
Reiner, who holds a doctorate in statistics from the University of Michigan, joined the Scott lab in September 2011. He has just accepted a position as assistant professor in the Department of Epidemiology and Biostatistics, Indiana University, Bloomington.
“The marked variation in transmission intensity that we detected indicates that intervention targets based on one-time estimates of the force of infection (FoI) could underestimate the level of effort needed to prevent disease,” the authors wrote in their abstract. “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.”
“There is no vaccine nor drug that is effective against this virus,” said Scott, who has studied dengue more than 25 years and is recognized as the leading expert in the ecology and epidemiology of the disease.
While vaccines are under development, it is not clear how they can be best applied when they are available, including in combination with other interventions like mosquito control, Scott said. “New disease prevention tools, in addition to vaccines, and an improved understanding of virus transmission dynamics, which will enhance surveillance and epidemic response, are needed to reduce the global burden of dengue.”
The work was supported by the RAPPID program of the Science and Technology Directory, Department of Homeland Security, and Fogarty International Center, National Institutes of Health; Innovative Vector Control Consortium; U.S. Department of Defense Global Emerging Infections Systems Research Program Work Unit; Military Infectious Disease Research Program Work Units; Deployed Warfighter Protection Program, Department of Defense; and a Wellcome Trust.