The World Health Organisation has raised the alarm over a possible chikungunya outbreak, two decades after its last widespread breakout. According to estimates, around 5.6 billion people in 119 countries are at risk.
Dr Subramanian Swaminathan, Director, Infectious Diseases, Gleneagles BGS Hospital, Bengaluru and Dr Akshay Challani, Lead and Senior Consultant Critical Care and Medical Advisor, Apollo Hospitals, Navi Mumbai, answered some basic questions about the mosquito-borne disease.
Why is chikungunya re-emerging globally in 2025?
There are multiple interlinked factors. Climate change is significantly altering the breeding patterns of Aedes mosquitoes, particularly Aedes aegypti and Aedes albopictus, the carriers of the virus. Rising temperatures and unpredictable, erratic rainfall are expanding mosquito habitats into new geographies, including urban areas previously considered safe.
Rapid urbanisation, crowded living conditions, and poor sanitation further provide ideal environments for mosquito proliferation. Additionally, increased international travel and post-pandemic global mobility allow the virus to spread more easily across borders. The absence of a licensed vaccine, along with waning immunity in populations, means large numbers remain vulnerable, allowing outbreaks to occur repeatedly.
What are the associated symptoms and complications? How long do they persist?
Chikungunya infection typically begins abruptly, with a sudden high fever, intense joint pain, particularly in wrists, ankles, and small joints, severe fatigue, headache, muscle pain, and sometimes rash. While the fever usually subsides within a few days, the joint pain and stiffness often persist for weeks or even months, sometimes mimicking chronic arthritis. This lingering joint inflammation can be debilitating, especially for elderly patients or those with existing health conditions. Some individuals may also develop serious complications such as heart inflammation, neurological effects, or chronic inflammatory arthritis. Beyond physical symptoms, many patients report prolonged fatigue and low mood long after the infection has cleared, indicating a broader impact on overall health.
What factors contribute to recurrence and relapse of chikungunya in individuals and communities?
For individuals, persistent inflammation causes flare-ups of joint pain and fatigue weeks or even months after initial recovery, a phenomenon known as post-viral sequelae. Community-level factors driving recurrent outbreaks include ineffective mosquito control, stagnant water in urban slums, poor sanitation, and diminishing public vigilance over time. Since chikungunya infection does generally provide long-lasting immunity to those infected, repeated outbreaks occur primarily because mosquitoes remain unchecked in breeding-prone environments, keeping uninfected family members and neighbours vulnerable. The cyclical nature of poor sanitation, crowded living conditions, and lack of a vaccine perpetuates this cycle of recurrence.
What preventive measures can be taken against outbreaks?
Prevention requires an approach combining individual actions with collective public health efforts. Individuals can significantly reduce risk by eliminating stagnant water around homes, consistently using mosquito repellents, sleeping under mosquito nets, wearing protective clothing, and staying informed about early symptoms to seek timely medical help. At the community level, regular fogging, larvicide spraying, clearing breeding sites like clogged drains, and running sustained mass awareness campaigns are essential. Long-term strategies include improving urban planning and reinforcing resilient public health infrastructure. Although there is currently no licensed vaccine, promising candidates in advanced clinical trials offer hope for better future control in endemic areas.
Are there any particular vulnerabilities in India?
India faces significant vulnerabilities due to its tropical climate, high population density, and widespread urban slums with inadequate drainage and sanitation. Extended monsoons, heat, and frequent flooding exacerbate mosquito breeding conditions. Many neighbourhoods struggle with clogged drains and overflowing garbage, which become unnoticed breeding grounds. The simultaneous circulation of chikungunya with other vector-borne diseases like dengue and malaria strains healthcare resources, especially post-monsoon, when mosquito populations peak. Vulnerable groups include migrant workers, residents of informal housing clusters, the elderly, immunocompromised individuals, and those with comorbidities. These layered challenges require continuous, focused, and year-round prevention efforts rather than seasonal interventions alone.