According to a recent study led by the University of Florida and the Johns Hopkins Bloomberg School of Public Health, most cases of dengue fever occur very close to an individual’s home and are transmitted from the same family of mosquitoes.
Findings from the study were published in the March 24 issue of the journal Science.
To gather data, the researchers genetically sequenced the viruses of 640 dengue infections that occurred in Bangkok, Thailand between 1994 and 2010. They then pinpointed each infection on a map showing where 17,291 infected people lived.
Their results showed that 60 percent of all dengue infections in people living less than 200 meters apart occurred from the same mosquito transmission family.
“Our findings suggest that large urban centers provide a source of dengue [genetic] diversity that could possibly be dispersed to other areas of the country and world,” Derek Cummings, professor of biology at Florida’s Emerging Pathogens Institute, said. “This suggests that these areas might be where intense competition is occurring between dengue viruses.”
The researchers estimated there were approximately 160 chains of transmission circulating Bangkok in a given season. They also estimate the virus will typically stay in one area for the first season, then eventually mix across the country by the next season. The research teams noted, however, that it appeared the virus would typically stay within a country’s borders and that they didn’t quite understand why.
“We often think that pathogens don’t respect borders,” Henrik Salje, lead author of the study, said. “While clearly there is a lot of human mobility between the countries in the region, it does not appear to be enough to connect their dengue epidemics.”