The Spread of Chikungunya Virus and the Impact of Climate Change
Chikungunya virus is typically found in tropical and subtropical regions, including Central and South America, the Caribbean, the Indian Ocean islands, South and Southeast Asia, and Africa. However, a recent study has warned that this virus could soon spread to Europe and North America due to the effects of climate change.
Scientists from Zhejiang Chinese Medical University in Hangzhou, China, have highlighted that climate change is creating ideal conditions for two mosquito vectors—Aedes aegypti and Aedes albopictus—in major cities across the globe. Dr Yang Wu, an author of the study, explained that climate change affects chikungunya mainly by altering the habitats where its mosquito vectors can thrive.
The Asian tiger mosquito, in particular, plays a significant role in the predicted distribution of the virus, accounting for over 70% of the model’s results. This mosquito species is more tolerant of cooler conditions compared to the yellow fever mosquito, which means warming temperatures could enable it to establish itself in areas that were previously too cold. Once these mosquitoes become established, the likelihood of local chikungunya transmission increases significantly.
Although the virus is rarely fatal, it can cause prolonged joint pain and disability. The name “Chikungunya” originates from the Kimakonde language, meaning “to become contorted.” The disease has been around since 1952 and is caused by a virus transmitted through Aedes mosquitoes. Despite approximately 33,000 cases reported this year, Chikungunya remains one of the most neglected tropical diseases globally, according to the World Health Organisation (WHO).
Currently, most outbreaks occur in tropical and subtropical regions. However, Dr Ye Xu, another author of the study, predicts that by 2100, this could change dramatically. She stated that at present, 139 countries or regions—covering 21.3% of the world’s land area—are considered risk zones for the virus. Under climate change models, the virus is expected to expand further northward into temperate regions, particularly northeastern North America, central Europe, and East Asia.
In their research, the team modeled how the ranges of the yellow fever mosquito and the Asian tiger mosquito will shift as temperatures rise. Their findings suggest that north-central Europe, northeastern North America, and eastern Asia are set to become future hotspots for the virus.
Dr Xu emphasized that while the public does not need to panic, health systems should prepare early. She suggested that public health officials take proactive steps such as tracking Aedes mosquitoes, training doctors to recognize chikungunya quickly, strengthening mosquito control measures, and setting up rapid-response plans before outbreaks occur. These actions are especially important in temperate regions where the disease has not been a routine public health concern.
Limiting global warming and investing in basic preparedness could help reduce the chances of large outbreaks. Although the study did not identify the UK as a future hotspot, there has been a noticeable increase in cases within the country. In 2024, 112 confirmed and probable cases of chikungunya were reported among travelers returning to England, Wales, and Northern Ireland—nearly 1.5 times the number recorded in 2023. Most of these cases were linked to travel to India, followed by Pakistan and Brazil.
The UK Health Security Agency (UKHSA) noted that there is currently no risk of onward transmission in the UK because there is no evidence of invasive mosquito species being established. However, they added that climate change may increase the suitability of certain areas in the UK for these mosquitoes.
What is Chikungunya?
Chikungunya is a disease caused by the chikungunya virus, which is transmitted to humans by infected mosquitoes. Large outbreaks and sporadic cases have been reported mostly in the Americas, Asia, and Africa, with occasional smaller outbreaks in Europe. The symptoms of chikungunya resemble those of dengue and Zika, making it challenging to diagnose and leading to difficulties in accurately determining the number of infections.
Common symptoms include fever and severe joint pain, which can be debilitating and prolonged. Other symptoms may involve joint swelling, muscle pain, headache, nausea, fatigue, and rash. While there are two vaccines approved in several countries and recommended for high-risk populations, they are not yet widely available. The WHO and external experts are reviewing vaccine trial data to determine potential recommendations for use.
There is currently no specific antiviral treatment for chikungunya virus infections. However, medications such as paracetamol can be used to manage fever and pain. Severe symptoms and deaths from chikungunya are rare and usually affect young babies or elderly individuals with other health conditions.
