The World Health Organization (WHO) has issued a grim warning about a large-scale outbreak of the chikungunya virus is gaining speed—and the initial symptoms are ominously reminiscent. In comparison to the catastrophic 2004–2005 epidemic that started in the Indian Ocean region and later reached hundreds of thousands of people all over the world, WHO experts are calling on governments to take action before the same repeats itself.Dr. Diana Rojas Alvarez, WHO’s technical lead for chikungunya, told reporters in Geneva that the virus is now being detected in 119 countries, putting 5.6 billion people at risk. The warning is not hypothetical. Already in 2025, regions like Réunion, Mayotte, and Mauritius have seen major outbreaks. In Réunion alone, nearly one-third of the population is estimated to have been infected.What’s different this time is the potential for global scale and speed, thanks to interconnected travel, shifting climates, and growing populations of virus-carrying mosquitoes. And while the name “chikungunya” may not be widely known outside scientific circles, its impact can be life-altering—if not deadly.Why Is Chikungunya Dangerous?Chikungunya is a mosquito-borne viral illness caused by the chikungunya virus (CHIKV), typically transmitted by Aedes aegypti and Aedes albopictus, the same mosquitoes that spread dengue and Zika viruses. These insects bite mostly during the daytime with peak activity in the morning and late afternoon.The virus causes sudden onset of high fever, intense joint pain, headaches, rash, and muscle aches. The joint pain can become so severe that it bends sufferers into contorted postures—an origin of the disease’s name, which comes from a Makonde word meaning “that which bends up.”While the majority of patients recover within a week, some symptoms—particularly joint pain—can persist for months or even years. In rare cases, chikungunya can cause neurological, cardiac or ophthalmic complications. Newborns, older adults and those with chronic medical conditions face a higher risk of severe disease or death.Although the case fatality rate remains under 1%, WHO warns that large-scale outbreaks could mean thousands of deaths, especially in countries with under-resourced health systems.According to WHO, the trajectory of the current outbreaks strangely mirrors that of the 2004–2005 epidemic. It began in small island nations before spreading across the Indian Ocean and into Asia, Africa and beyond. Today, similar trends are being observed with:Réunion has reported over 51,000 cases as of May 2025Mayotte, another French territory, has recorded 560 cases, pushing it into an epidemic phaseMadagascar, Somalia, and Kenya are now reporting new clustersSouth Asia is experiencing epidemic-level transmissionFrance has confirmed 30 local cases across 12 regions, with the largest cluster in Salon-de-ProvenceItaly reported its first locally acquired case since 2017 in PiacenzaEven countries like Portugal have reported dengue and chikungunya cases in 2025, highlighting how climate change and international travel are making vector-borne illnesses harder to contain.Dr. Rojas Alvarez emphasized, “We are raising the alarm early so countries can prepare early—strengthening detection, prevention, and response systems is key.”Why Europe and the US Should Pay Attention?For decades, chikungunya was seen as a “tropical” disease, limited to warmer parts of Asia, Africa, and the Americas.The Aedes albopictus, or tiger mosquito, is expanding its range northward due to warming temperatures and human-driven climate change. These mosquitoes have already become established in parts of southern Europe and even the southeastern United States. And with imported cases from travelers on the rise, localized outbreaks are becoming increasingly plausible.The European Centre for Disease Prevention and Control (ECDC) recently launched updated guidance on mosquito-borne illnesses and emphasized the growing risk of local transmission. In addition to chikungunya, local dengue cases have been reported in Italy, France and Portugal in 2025.How Can People Protect Themselves?There’s no antiviral treatment for chikungunya, and supportive care—hydration, rest, and pain relief—is the mainstay of treatment. That makes prevention the most powerful tool. The WHO and ECDC recommend the following steps:Use mosquito repellents with DEET or picaridin on skin and clothingWear long sleeves and pants, especially during mosquito-active hoursInstall screens on windows and doors, and use insecticide-treated mosquito nets when sleepingEmpty standing water from containers like buckets, pots, and old tires, where mosquitoes lay eggsAvoid outdoor activity during early morning and late afternoon, especially in outbreak zonesHas Vaccine Become The New Line of Defense?In a significant step, UK has approved a chikungunya vaccine which contains a weakened version of the virus that trains the immune system to produce antibodies. The vaccine is prescription-only and is currently recommended for people traveling to high-risk areas. However, it is not without limitations. The Commission on Human Medicines has advised caution in people aged 65 and older, pending further evaluation.Until now, all we had were repellents and mosquito nets. With this vaccine, people who travel frequently or live in endemic areas now have another layer of protection. Still, experts advise travelers to assess their personal risk. If you're taking a one-off trip to France, your risk is low but if you're planning repeated travel to areas with outbreaks, vaccination may be worthwhile.Does Climate Change Affect Incidence Rate?Chikungunya and other mosquito-borne diseases are moving into new regions and our global health systems are scrambling to keep up. The convergence of climate change, urbanization, and international mobility is creating the perfect storm for diseases like chikungunya, dengue, and Zika to flourish.As WHO warns, the time to act is now. That means not only educating the public and travelers but also investing in surveillance, vector control, and vaccine distribution especially in lower-income countries where health infrastructure is fragile. In 2005, the world was caught off guard and in 2025, we don’t have that excuse.