Planning a sunny getaway? You might want to pack a mosquito net.
Health experts are warning about an emerging threat making waves in popular vacation destinations, as cases of the Oropouche virus have been reported in US and Canadian travelers returning from Bolivia, Brazil, Colombia, Cuba and Peru.
While much about the tropical disease remains unknown, the recent spate of infections has raised questions about whether it could become the next Zika virus. Here’s everything you need to know about this potential travel headache.
What is the Oropouche virus?
The Oropouche virus is primarily spread through the bites of small flies called midges, as well as certain species of mosquitoes.
It’s commonly referred to as “sloth fever” because the virus was first identified in the slow-moving mammal, which researchers believe played a key role in its spread.
Since its discovery in 1955, there have been an estimated 500,000 cases of Oropouche virus, mostly around the Amazon Basin. However, starting in late 2023, the virus has started popping up in new areas of South America and the Caribbean where it hadn’t been seen before, raising concerns about its expanding reach.
As of March 11, the CDC has identified 109 cases of imported sloth fever in US travelers from seven states, including one case in New York. The majority of the illnesses have been reported in Florida, with 103 cases so far in 2024 and the first three months of 2025.
Symptoms to watch for
If you’re bitten by a mosquito or midge carrying the Oropouche virus, symptoms can appear anywhere from 3 to 10 days later, according to the CDC.
The most common symptoms include a sudden fever and severe headache, often resembling those of other tropical illnesses like dengue, chikungunya, Zika or malaria. Additional symptoms can include chills, muscle aches, joint pain, light sensitivity, dizziness, pain behind the eyes, nausea, vomiting and a rash.
In most cases, symptoms last less than a week, with most people fully recovering within a month. However, the CDC notes that some individuals may experience a recurrence of symptoms, either a few days or even weeks later.
In rare cases, the Oropouche virus can cause more severe conditions, such as excessive bleeding, brain swelling, or Guillain-Barré syndrome, which can lead to muscle weakness, numbness and paralysis.
While fatalities are uncommon, there have been a few instances where the virus has proven fatal.
Pregnancy risk
The Oropouche virus doesn’t just pose a threat to adults and children — it can also be transmitted from a pregnant person to their unborn fetus, with potentially devastating consequences.
Infection during pregnancy has been linked to stillbirths, miscarriages, and other serious risks to the fetus, such as low birth weight, skull collapse, club foot, and microcephaly, a condition where brain development is significantly impaired.
Given these risks, the CDC is advising pregnant women to reconsider any nonessential travel to areas where Oropouche outbreaks have recently been reported.
How is sloth fever treated?
Unfortunately, there’s no vaccine to prevent or specific medication to treat Oropouche virus.
To manage symptoms, the CDC recommends getting plenty of rest, staying hydrated, and taking over-the-counter pain relievers. But don’t reach for aspirin and other nonsteroidal anti-inflammatory drugs, as they can increase the risk of excessive bleeding.
For those with more severe symptoms, additional medical care or even hospitalization may be required to ensure proper treatment and recovery.
How to protect yourself from the Oropouche virus?
To steer clear of the Oropouche virus, your best bet is to minimize exposure to mosquito and midge bites.
The CDC recommends wearing loose, long-sleeved shirts and pants when traveling to regions where the virus is circulating.
Make sure your accommodations are bug-proof by using window and door screens, or set up a fan outdoors to keep the pests at bay. And of course, don’t forget to bring along insect repellent.
A recent study also found traces of Oropouche virus in the semen of an infected individual for the first time. While no sexual transmission cases have been reported, the CDC suggests that travelers who are worried about contracting or passing the virus through sex to consider using condoms or abstaining from sex during travel and for six weeks after returning home.
Could sloth fever start to spread in the US?
While Oropouche cases have been reported in American travelers, the risk of widespread transmission in the continental US remains low.
The CDC notes that the US has a different climate and distinct species mosquitoes and midges compared to those in regions where the virus is common. Additionally, factors like air conditioning make it less likely for the virus to take root.
However, the agency does warn that infections could still pop up in certain areas.
