Key Points

The virus, common in tropical and subtropical regions, including Asia, Africa, and South America, leads to symptoms such as acute fever, followed by debilitating joint pain that can last for months.

Though rarely fatal, the chikungunya virus can be particularly severe for high-risk individuals, including newborns and older adults.

In a new study, published in Science Advances, researchers at the University of Notre Dame, US, analysed more than 80 outbreaks of chikungunya virus to improve the prediction of future outbreaks and inform vaccine trial development.

"Chikungunya outbreaks are unpredictable in both size and severity," said Alex Perkins, Professor of infectious disease epidemiology in the Department of Biological Sciences.

"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," Perkins added.

For the study, the team reconstructed and analysed 86 chikungunya outbreaks, creating the largest comparative dataset of its kind.

Chikungunya was first identified in the 1950s. Outbreaks have become increasingly frequent and widespread, but they're also sporadic and difficult to predict, posing a challenge to public health officials when it comes to planning for and preventing infections.

Changes in outbreaks of chikungunya, transmitted by bites from infected mosquitoes -- Aedes aegypti or Aedes albopictus are the primary vectors -- and other mosquito-borne illnesses are often considered in relation to climate change, as warmer, more humid conditions can promote mosquito activity.

But Perkins noted that the study showed that climate isn't necessarily the most important factor when trying to predict the severity of an outbreak of disease caused by a virus like chikungunya.

"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," the expert added.

- IANS