Deadly Mosquito-Borne Chikungunya Virus Shows Up in U.S. Travelers—How to Stay Safe

As a walking mosquito magnet, you won’t find me leaving the house without bug spray. (I swear a giant “Bite Me” sign follows me wherever I go.) Mosquito bites are uncomfortable, super itchy, and just plain ugly. This is also why I always carry anti-itch cream, because I have no self-restraint. That said, there’s a mega mosquito on the loose that we all need to be on the lookout for this summer.

The Centers for Disease Control and Prevention (CDC) is warning about the deadly mosquito-borne chikungunya virus, which is gaining prevalence in South Asia and Europe, and now affecting U.S. travelers. Here’s everything we know.

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What is the chikungunya virus?

According to the World Health Organization (WHO), the chikungunya virus is transmitted to humans by the bites of infected female Aedes aegypti and Aedes albopictus mosquitoes, also known as tiger mosquitoes. This species is also linked to the Zika virus.

If you live in tropical regions with warm temperatures and high humidity, you know mosquitoes are most active in the hours after sunset. However, tiger mosquitoes tend to attack “primarily during daylight hours,” says the WHO.

Although rarely fatal, the chikungunya virus can cause “an abrupt onset” of symptoms. These typically appear within four to eight days post-bite and can linger up to 12 days—though, in most cases, mild symptoms subside by the third day. Chikungunya is known for causing “debilitating” joint pain that can last for weeks or months.

“The name ‘chikungunya’ derives from a word in the Kimakonde language of southern Tanzania, meaning ‘that which bends up and describes the stooped appearance of infected people with severe joint pain (arthralgia),'” explains the WHO.

Other common symptoms of the chikungunya virus include:

• Fever
• Muscle pain
• Headache
• Nausea
• Fatigue
• Rash

In healthy people, full recovery is expected. However, the elderly and people who are pregnant or immunocompromised are at higher risk. In more advanced cases, hospitalization might be necessary as the virus can cause:

• Eye, heart, and neurological complications
• Organ damage
• Death

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Where is the chikungunya virus spreading?

Chikungunya isn’t spreading locally in the U.S., but there have been incidences of travelers bringing the virus into the country. Thus far in 2025, the CDC has reported 45 travel-associated cases of chikungunya. This refers to people who became infected with chikungunya while in another country, prior to visiting/returning to the U.S.

As Best Life previously reported, “It’s not endemic in the U.S., mainly reported in travelers returning from affected areas in Asia, Africa, or the Indian Ocean, per the CDC. However, in late 2013, local transmission of the virus (meaning mosquitoes in the area were infected and spreading the virus to people) was reported in Caribbean countries and territories. The following year, the virus was reported in U.S. travelers returning from these affected areas in the Americas, with local transmission then identified in Florida, Puerto Rico, Texas, and the U.S. Virgin Islands.”

But now, chikungunya cases are ramping up across the globe.

“Chikungunya is not a disease that is widely known, but it has been detected and transmitted in 119 countries globally, putting 5.6 billion people at risk,” WHO medical officer Diana Rojas Alvarez, PhD, said in a recent press conference, as reported by Science Alert.

The virus has made landfall in Madagascar, Somalia, and Kenya, with epidemic transmission also occurring in South Asia. “One-third of the population of Reunion is estimated to have been infected already,” said Rojas Alvarez.

A chikungunya outbreak has also been confirmed in the Indian Ocean islands, which is fueling local transmission in Europe—specifically in France and possibly Italy.

Rojas Alvarez said, “these patterns of transmission” have medical experts on high alert.

“Because these patterns of transmission were seen in the outbreak from 2004 onwards, WHO is calling for urgent action to prevent history from repeating itself,” she said.

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Is there a vaccine for the chikungunya virus?

The IXCHIQ vaccine (made by Valneva) is currently available for adults 18 and over. It’s a “live-attenuated vaccine,” which means it “uses a weakened form of the chikungunya virus to prompt an immune response to help prevent disease,” per the CDC. It was licensed by the U.S. Food and Drug Administration (FDA) in Nov. 2023.

“According to a press release from Valneva, the single-dose shot might also be considered for those traveling to an area where there is evidence of transmission (not a full outbreak) in the last five years. This includes travelers older than 65 with underlying conditions who have a moderate risk of exposure to mosquitoes, and those traveling for longer than six months. It is also recommended for laboratory workers who could be exposed to chikungunya,” Best Life previously explained.