The symptoms of chikungunya manifest swiftly — an acute fever followed by debilitating joint pain that can persist for months. Although rarely fatal, this mosquito-borne virus poses a significant threat to high-risk groups, including newborns and older adults. While chikungunya is prevalent in tropical and subtropical regions such as Asia, Africa, and South America, public health officials have noted its spread to Europe and recently confirmed a case in Long Island, New York.
In response to these outbreaks, the Centers for Disease Control and Prevention (CDC) have issued health advisories for travelers to regions including Bangladesh, Cuba, Guangdong Province in China, Kenya, Madagascar, Somalia, and Sri Lanka. In Guangdong Province, an “unprecedented” outbreak led Chinese authorities to enforce quarantine measures for suspected cases, alongside widespread use of mosquito repellent and insecticide treatments in affected areas.
Groundbreaking Study on Chikungunya Outbreaks
A new study published in Science Advances by researchers at the University of Notre Dame has analyzed over 80 chikungunya outbreaks to enhance the prediction of future occurrences and inform vaccine trial development. Alex Perkins, the Ann and Daniel Monahan Collegiate Professor of infectious disease epidemiology and co-author of the study, emphasized the unpredictability of chikungunya outbreaks.
“Chikungunya outbreaks are unpredictable in both size and severity,” said Perkins. “You can have one outbreak that infects just a few people, and another in a similar setting that infects tens of thousands. That unpredictability is what makes public health planning — and vaccine development — so difficult.”
Leading the study, Alexander Meyer, a postdoctoral researcher in Perkins’ lab, along with his team, reconstructed and analyzed 86 outbreaks, creating the largest comparative dataset of its kind. “Instead of looking at outbreaks in isolation, looking at many, all of which varied in size and severity, allowed us to search for patterns among them,” Meyer explained.
Historical Context and Transmission Factors
First identified in the 1950s, chikungunya outbreaks have become more frequent and widespread, yet remain sporadic and difficult to predict. This poses a challenge for public health officials in planning and preventing infections. The virus is primarily transmitted by bites from infected mosquitoes, specifically Aedes aegypti or Aedes albopictus.
Changes in chikungunya and other mosquito-borne illnesses are often linked to climate change, as warmer, more humid conditions can increase mosquito activity. However, Perkins noted that climate is not necessarily the most critical factor in predicting outbreak severity.
“Climate factors like temperature and rainfall can tell us where outbreaks are possible, but this study shows that they don’t help very much in predicting how severe they will be,” he said. “Local conditions matter — things like housing quality, mosquito density and how communities respond. Some variation is simply due to chance. That randomness is part of the story, too.”
Implications for Vaccine Development
Currently, only two vaccines for chikungunya have received regulatory approval, yet they are not widely available in regions where the virus is most prevalent. The comprehensive dataset from this study is invaluable for vaccine development, as accurate predictions of outbreak locations are essential for conducting trials and assessing vaccine efficacy.
The study underscores the importance of a detailed analysis of past outbreaks to better prepare public health officials for future occurrences, ultimately protecting vulnerable populations and supporting vaccine development efforts.
Additional co-authors of the study include Kathryn B. Anderson from the State University of New York, Natalie Dean at Emory University, and Sandra Mendoza Guerrero and Steven T. Stoddard at Bavarian Nordic Inc., which funded the study. The research also received support from the Office of the Assistant Secretary of Defense for Health Affairs.
