Daijiworld Media Network - New Delhi

New Delhi, Oct 4: Chikungunya outbreaks are highly unpredictable, both in how many people they affect and how severe the symptoms can be, according to a new study published in Science Advances. Researchers from the University of Notre Dame analyzed data from 86 outbreaks of the mosquito-borne virus, making it the largest comparative study of chikungunya to date.

Chikungunya, transmitted by Aedes aegypti and Aedes albopictus mosquitoes, is common in tropical and subtropical regions such as Asia, Africa, and South America. While rarely fatal, it causes acute fever followed by prolonged and often debilitating joint pain, especially affecting newborns and the elderly more severely.

“What makes chikungunya so difficult to plan for is that its outbreaks are incredibly variable,” said Professor Alex Perkins, an infectious disease expert at Notre Dame. “One setting might see just a handful of cases, while another, under seemingly similar conditions, experiences tens of thousands.”

Although climate conditions like temperature and rainfall can influence mosquito activity and help determine where outbreaks are possible, Perkins noted that they are poor indicators of how severe an outbreak will be. The study highlights that local factors — such as housing quality, mosquito population density, and how quickly communities respond — play a more critical role. In some cases, sheer randomness contributes to outbreak patterns.

Since being identified in the 1950s, chikungunya outbreaks have grown more frequent and widespread, but remain sporadic and hard to forecast. This unpredictability poses major challenges for public health officials, especially in planning vaccine trials and allocating resources effectively.

The findings underscore the importance of strengthening local surveillance, improving living conditions, and enhancing community response efforts — rather than relying solely on climate-based models to predict outbreak severity.