Health officials are urging Americans headed overseas to take extra precautions after a painful mosquito-borne illness spread to dozens of countries this year, infecting hundreds of thousands of people worldwide.
The Centers for Disease Control and Prevention (CDC) issued new travel advisories this month, warning U.S. citizens about chikungunya, a virus that causes severe joint pain and has no specific treatment. The disease has been detected in active outbreaks across Bangladesh, Cuba, China's Guangdong Province, and Sri Lanka.
Americans visiting eight other nations face heightened risk even without confirmed outbreaks. Those destinations include Brazil, Colombia, India, Mexico, Nigeria, Pakistan, the Philippines, and Thailand. The advisory notes these countries have reported at least one laboratory-confirmed case among U.S. travelers annually over the past five years.
So far in 2025, 228 Americans have contracted the virus while traveling abroad, with one case acquired domestically within the United States, according to CDC data reported to ArboNET. No locally transmitted cases have been documented in U.S. states or territories since 2019.
The disease poses particular danger for pregnant women, young children, and older adults, according to the World Health Organization. While most people recover, the joint pain can persist for weeks, months, or even years in some patients.
"Chikungunya can cause large outbreaks with high attack rates, affecting one-third to three-quarters of immunologically susceptible populations," the WHO said in an October update.
Globally, more than 445,000 suspected and confirmed cases have been reported from 40 countries between January and September of this year, with 155 deaths, the WHO reported. Brazil accounted for nearly 96 percent of cases in the Americas with 96,159 confirmed infections and 111 deaths.
China is experiencing its largest documented outbreak on record, with more than 16,000 laboratory-confirmed cases reported in Guangdong Province through late September. The outbreak spread to 21 cities, with Foshan reporting over 10,000 cases alone.
The virus spreads through bites from infected Aedes mosquitoes, the same species that transmit dengue and Zika. These mosquitoes bite primarily during daylight hours and breed in standing water found in containers around homes and yards.
Symptoms typically appear four to eight days after an infected mosquito bite. The illness starts suddenly with fever and debilitating joint pain, often accompanied by swelling, muscle aches, headache, nausea, fatigue, and rash.
"Most patients recover fully from the infection; however, occasional cases of eye, heart, and neurological complications have been reported," the WHO said.
No antiviral medications exist to treat the disease. Doctors recommend pain relievers like acetaminophen, rest, and drinking plenty of fluids to manage symptoms.
Two vaccines have received regulatory approval in several countries, but they are not yet widely available or in common use. The agency is currently reviewing vaccine data to potentially issue recommendations.
The CDC recommends vaccination for travelers visiting areas with active outbreaks. Those planning extended stays in high-risk countries without current outbreaks may also consider getting vaccinated.
For Americans who cannot avoid traveling to affected regions, health officials stress prevention through avoiding mosquito bites. The CDC advises wearing clothing that covers exposed skin, using window and door screens, and applying insect repellent.
Travelers should also discard standing water around their living area by emptying containers weekly and properly disposing of waste that could collect rainwater.
The CDC advises anyone who develops symptoms after traveling to affected areas to avoid further mosquito bites during the first week of the illness to prevent spreading the virus to others.