Most dengue infections transmitted in and around home
- Findings published in Science provide insight into how dengue spreads
- IVI ‘s Dr. In-Kyu Yoon co-authors study
March 21, 2017 - Outbreaks of the dengue virus appear to be largely driven by infections centered in and around the home, with the majority of cases related to one another occurring in people who live less than 200 meters apart, suggests new research led by the University of Florida, the Institut Pasteur, Walter Reed Army Institute of Research, the Ministry of Public Health of Thailand, the Queen Sirikit National Institute of Child Health and the Johns Hopkins Bloomberg School of Public Health. The International Vaccine Institute’s (IVI) Dr. In-Kyu Yoon, also Director of the Global Dengue & Aedes-Transmitted Diseases Consortium (GDAC), is among the co-authors. He previously was Chief of Virology at the Armed Forces Research Institute of Medical Sciences in Bangkok, Thailand.
The findings, published in the March 24 issue of Science, offer new insights into the spread of dengue — which infects more than 300 million people each year — and other flaviviruses such as Zika and yellow fever, and how governments and individuals might put in place more targeted and more effective mosquito control programs.
For their study, the researchers genetically sequenced the viruses of 640 dengue infections that occurred between 1994 and 2010 in both densely-populated Bangkok, Thailand and less densely populated regions outside the capital, then overlaid this information on a map showing where the people infected with the virus lived. Their results show that in people living fewer than 200 meters apart (typically in houses in the same neighborhood), 60 percent of dengue cases come from the same transmission chain, meaning they were infected by a virus that was only recently introduced into the area. In people who were separated by one to five kilometers, just three percent of cases came from the same transmission chain.
Forty percent of the world’s population live in areas where they are at risk for dengue, which is most common in Southeast Asia and the western Pacific islands and has been rapidly increasing in Latin America and the Caribbean. While most of the 300 million people who get dengue annually survive with few or no symptoms, more than two million per year develop more severe dengue, which kills more than 25,000 people each year — mostly children.
The researchers analyzed the genetic diversity of dengue viruses across Bangkok. They estimate that 160 separate chains of transmission co-circulate in Bangkok within a “dengue season,” which in Thailand is usually June to November. Across the city, they found that larger populations of humans support a larger diversity of dengue viruses.
“These findings are significant since they provide empirical evidence of the
importance of home location in dengue virus transmission,” said Dr. In-Kyu Yoon, IVI’s Deputy Director General of Science. “In addition, they highlight the role of population centers as important sources of dengue virus diversity.”
The research was supported by grants from the National Institutes of Health’s National Institute of Allergy and Infectious Diseases (R01AI114703-01 and R01 AI102939-01A1), the National Science Foundation (BCS-1202983) and the Global Emerging Infections Surveillance and Response System, a Division of the Armed Forces Health Surveillance Health Center.
About the International Vaccine Institute
The International Vaccine Institute (IVI) is the world’s only international organization devoted exclusively to developing and introducing new and improved vaccines to protect the world’s poorest people, especially children in developing countries. Established in 1997, IVI operates as an independent international organization under a treaty signed by 35 countries and the World Health Organization. The Institute conducts research in more than 20 countries of Asia, Africa and Latin America on vaccines against enteric and diarrheal infections, Japanese encephalitis, MERS-CoV, and dengue fever, and develops new and improved vaccines at its headquarters in Seoul, Republic of Korea. For more information, please visit http://www.ivi.int .
Tae Kyung Byun, IVI