Oliver J. Brady
Researchers predicted that the geographical range of dengue will expand to put more than 6 billion people — or 60% of the world’s population — at risk for infection by 2080, according to findings published in Nature Microbiology.
“Dengue is likely to continue its global spread but at a lower rate than previously thought,” Oliver J. Brady, DPhil, from the London School of Hygiene & Tropical Medicine, told Infectious Disease News. “Instead, it is areas where the disease is already endemic, like Southeast Asia and South America, that are likely to face the biggest growth in dengue risk as more and more of their populations move into high-risk urban areas. Africa also will see a big growth in risk, often in countries least able to cope with a new infectious disease threat.”
The role of climate change in the spread of dengue will be relatively small compared with that of population growth and increasing urbanization in tropical areas, Brady explained in a news release.
For their study, Brady and colleagues created a 2015 map of environmental suitability for dengue, then used modeling to project suitability in 2020, 2050 and 2080, according to the study.
Dengue, which is transmitted by mosquito bites, is common in tropical and subtropical countries, and is endemic in the United States territories of America Samoa, Guam, Puerto Rico and the U.S. Virgin Islands. The FDA recently approved Dengvaxia (Sanofi Pasteur), but the vaccine is available only for individuals previously infected with dengue because of safety concerns.
“Currently, no widely available drugs or vaccines are available, so clinicians must focus on providing good advice on how to avoid mosquito bites in high-risk areas and encourage affected people to seek treatment as soon as denguelike symptoms develop so clinicians can best manage the disease,” Brady said.
The African continent is projected to see the greatest shifts in dengue risk, namely in southern Africa and the Sahel in West Africa, according to the study.
The results conflict with other studies that predicted the expansion of dengue across continental Europe. Brady and colleagues concluded that there will likely be only several isolated areas around the Mediterranean that are affected, and the risk levels are projected to be low.
The risk will increase in the southeastern United States, coastal areas of China and Japan and inland regions of Australia, the researchers wrote.
Elsewhere, recent findings published in The Lancet Planetary Health by Yesim Tozan, PhD, assistant professor of global health at New York University College of Global Public Health, and colleagues highlighted interventions in Sri Lanka that have reduced dengue by 50%. Teams composed of public health authorities, police and military personnel conducted door-to-door inspections to identify and remove mosquito breeding sites, such as containers of stagnant water in or near homes.
“The public health sector can greatly benefit from investments in vector control programs and reduce the disease and economic burden of dengue in endemic settings if source reduction interventions are rigorously implemented and effectively coordinated across sectors, including ensuring community participation,” Tozan told Infectious Disease News.
Brady offered other examples of ways to curb dengue’s effect, including investments in robust surveillance programs to detect the arrival of infected mosquitoes before they become established. Sustainable urban growth will also play a role, he said – by Joe Gramigna
Liyanage P, et al. Lancet Planet Health. 2019;doi:10.1016/S2542-5196(19)30057-9.
Messina JP, et al. Nat Microbiol. 2019;doi:10.1038/s41564-019-0476-8.
Disclosures: The authors report no relevant financial disclosures.