Dengue study to focus on asymptomatic carriers

April 15, 2014 by Carol Clark
A NASA satellite image shows the metropolitan area of Iquitos, Peru, nestled in the Amazon Basin, on the banks of the Amazon River (lower left) and surrounded by smaller rivers, lakes and lagoons.

Dengue fever is a leading cause of illness and death in the tropics and subtropics, infecting as many as 400 million people annually, according to the CDC.

"Currently, the most effective way to control outbreaks is to spray for mosquitoes and help people to avoid getting bit by them," says Gonzalo Vazquez-Prokopec, a disease ecologist in Emory's Department of Environmental Sciences.

Vazquez-Prokopec is a co-principal investigator on a major dengue research project ongoing in Iquitos, Peru, which is honing in on ways to control outbreaks of the disease and more effectively treat infections. The National Institutes of Health recently awarded $7 million to the project team, led by the University of California, Davis, and also including the U.S. Navy, North Carolina State University, the University of Iowa, Tulane University and San Diego State.

Emory's portion of the grant – $1.3 million – will be used to study how people who are infected with a , but not showing symptoms, may contribute to the spread of dengue.

Infections can spread like wildlife through urban areas of the developing world where many people live in close quarters in substandard housing. Mosquitoes are the vectors of the disease, transmitting the four viruses that cause dengue between people.

The video will load shortly
For an earlier phase of the research project, Emory post-doc Donal Bisanzio created a data visualization, above, of the movement routines of people in Iquitos.

"It's a complex disease, made even more complicated by the fact that four different species of dengue viruses can interact with one another," Vazquez-Prokopec says. "And yet, we actually know more about these viruses than we do about the behaviors of the people who get infected with them."

The Emory research team also includes Uriel Kitron, chair of Emory's Department of Environmental Sciences, and Lance Waller, chair of the Department of Biostatistics and Bioinformatics at the Rollins School of Public Health.

Dengue is endemic in Iquitos, a city on the edge of the Amazon rainforest. A large portion of people who get infected do not experience the usual debilitating symptoms of dengue and continue going to work or visiting friends and relatives.

"We want to determine if these people are significant spreaders of the disease," Vazquez-Prokopec says.

The experiment will require participants to undergo blood tests and wear a device that uses a GPS to track their movements and a body temperature monitor to record any bouts of fever. The data from asymptomatic people who are infected will be analyzed along with spatial-temporal data on infected people who become sick during an outbreak. Ultimately, the project will infer the contribution of asymptomatic people by linking those data with mathematical models simulating virus spread within the city.

Previously, Vazquez-Prokopec and colleagues used GPS technology to quantify the movement and contact dynamics of nearly 600 residents of Iquitos, where most people are self-employed or hold several jobs to try and make ends meet. The results showed that the participants visited an average of six locations per day overall, compared to cities in North America and Europe where urbanites visit an average of two to four locations daily.

The researchers have also conducted spatial-temporal analyses of dengue outbreak patterns through two large neighborhoods of Iquitos. When a case of dengue was confirmed through a blood test, social workers would interview the patient, recording all the places he patient went during the 15 days leading up to the onset of fever. That study found that one of the main drivers for infection was people visiting friends and relatives in nearby homes, as opposed to large gathering places like schools.

"This large project will shed light onto something that hasn't been explored before: The role of people who are undetected by the health system in propagating dengue," says Vazquez-Prokopec.

Explore further: Tracking the spread of dengue fever: Domestic networks drive rapid transmission of human infection

Related Stories

Tracking the spread of dengue fever: Domestic networks drive rapid transmission of human infection

January 24, 2013
The mosquitoes that spread dengue fever tap into the domestic networks of humans, along with their bloodstreams, finds a study recently published in the Proceedings of the National Academy of Sciences (PNAS).

UN attacks biting bugs that spread diseases

April 7, 2014
Nobody likes mosquitoes, and the World Health Organization blames them for an array of diseases that kill a million people each year and threaten the health of half the world's people.

Swedish researchers map the risks of new virus epidemic in Europe

April 8, 2014
The risk of dengue fever beginning to spread in Europe is imminent. According to researchers from Umeå University, this is no longer just an issue for the scientific community but also for politicians and policy makers, ...

Dengue outbreak kills 23 in Pakistan

September 26, 2013
An outbreak of dengue fever in northwest Pakistan's Swat valley has killed 23 people in the past month, but health officials said Thursday it was likely to subside as the weather cools in the coming weeks.

Tropical medicine study finds most rapid way to detect dengue

January 6, 2014
University of Hawaii Mānoa scientists have found that a commercially available, FDA-approved dengue detection kit bests the former "gold standard" test by producing results in under five hours.

Woman's death highlights danger of overlooking dengue

January 24, 2014
(HealthDay)—The case of a Texas woman who died after becoming infected in New Mexico with the mosquito-borne dengue virus highlights a need for U.S. doctors to recognize the disease early, experts say.

Recommended for you

Google searches can be used to track dengue in underdeveloped countries

July 20, 2017
An analytical tool that combines Google search data with government-provided clinical data can quickly and accurately track dengue fever in less-developed countries, according to new research published in PLOS Computational ...

MRSA emerged years before methicillin was even discovered

July 19, 2017
Methicillin resistant Staphylococcus aureus (MRSA) emerged long before the introduction of the antibiotic methicillin into clinical practice, according to a study published in the open access journal Genome Biology. It was ...

New test distinguishes Zika from similar viral infections

July 18, 2017
A new test is the best-to-date in differentiating Zika virus infections from infections caused by similar viruses. The antibody-based assay, developed by researchers at UC Berkeley and Humabs BioMed, a private biotechnology ...

'Superbugs' study reveals complex picture of E. coli bloodstream infections

July 18, 2017
The first large-scale genetic study of Escherichia coli (E. coli) cultured from patients with bloodstream infections in England showed that drug resistant 'superbugs' are not always out-competing other strains. Research by ...

Ebola virus can persist in monkeys that survived disease, even after symptoms disappear

July 17, 2017
Ebola virus infection can be detected in rhesus monkeys that survive the disease and no longer show symptoms, according to research published by Army scientists in today's online edition of the journal Nature Microbiology. ...

Mountain gorillas have herpes virus similar to that found in humans

July 13, 2017
Scientists from the University of California, Davis, have detected a herpes virus in wild mountain gorillas that is very similar to the Epstein-Barr virus in humans, according to a study published today in the journal Scientific ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.