To control mosquito-borne diseases like dengue, researchers need to look at the behavior of people, not just the insect that transmits the disease, according to newly published research by Steven Stoddard of the University of California, Davis, and colleagues.

The study, which appears in the July 21 issue of the journal PLoS Neglected Tropical Diseases at http://www.plosntds.org, presents the work of an international, multidisciplinary team of vector biologists, sociologists and virologists studying dengue in Iquitos, Peru.

Understanding the behavior of the people and mosquitoes can lead to better surveillance, intervention and improved prevention of diseases like dengue, said Stoddard, a postdoctoral scholar in the laboratory of Professor Thomas Scott of the UC Davis Department of Entomology. Dengue appeared in Iquitos in 1990, and since then its incidence rate has varied from approximately 5 percent to more than 30 percent after new virus serotype introductions, Stoddard said.

No vaccine or cure is currently available for dengue, which is transmitted by the tiger-striped, day-biting mosquito Aedes aegypti. Some 2.5 billion to 3 billion people are at risk for dengue each year, and 50 million to 100 million suffer from clinically apparent dengue, according to Scott.

To track individual human movement, the research team uses small GPS devices and culturally sensitive interviews that were developed by the team.

“We do not necessarily expect to be able to identify actual places or individuals where the risk is greatest because the population dynamics of the vector and the behavior of the hosts are too transient,” Stoddard said. “We do hope, however, to arrive at a much better understanding of the mechanics of transmission — like why epidemics occur even when vector abundances are low — and of the types of places and types of individuals at greatest risk.”

The researchers developed a conceptual model showing that the relevance of human movement at a particular scale depends on mosquito behavior. Focusing on Aedes aegypti, they illustrated how biting behavior combined with fine-scale movements of individual humans engaged in daily routines can influence disease transmission. They also outlined several considerations for designing epidemiological studies to encourage studies of individual human movement.

“We hope to arrive at a better notion of the spatial scale on which dengue transmission occurs and from an operational standpoint, at what scale to focus interventions,” Stoddard said. Another aim is to encourage researchers of other mosquito-borne diseases, such as malaria, “to conduct more incisive examinations of individual human movements.”

The research paper was authored by vector biologists Stoddard, Scott and vector biologist Amy Morrison of the UC Davis Department of Entomology; vector biologists Gonzalo Vasquez-Prokopec and Uriel Kitron of the Department of Environmental Studies, Emory University, Atlanta; virologist Tadeuz Kochel of the U.S. Naval Medical Research Center Detachment, Lima and Iquitos, Peru; sociologist John Elder of the Graduate School of Public Health, San Diego State University; and sociologist Valerie Paz Soldan of Tulane University, New Orleans.

This research is supported by a five-year award to Scott from the National Institutes of Health.

About UC Davis

For 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has 31,000 students, an annual research budget that exceeds $500 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science -- and advanced degrees from six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.