Twenty-one Americans have been diagnosed with a virus that originates from sloths and is spread by mosquitoes.
According to the U.S. Centers for Disease Control (CDC), the patients were diagnosed with the Oropouche virus after returning to the U.S. from Cuba.
Twenty of the cases were in Florida and one in New York. The most common symptoms were fever, muscle aches, headache, fatigue and stiffness.
Three patients were hospitalized, but there were no deaths.
The Oropouche virus is spread by mosquitoes in tropical parts of the Caribbean and South America. Since the end of last year, the virus has caused an unprecedented outbreak.
The Oropouche virus is also called sloth fever, not because it is transmitted by sloths, but because the animals can be carriers of the disease
The Oropouche virus is primarily spread by bites from an insect called a midge. Sometimes mosquitoes also carry it
In rare cases it can lead to swelling of the brain and death. Earlier this year it claimed the lives of two healthy Brazilian women.
In 2024, more than 8,000 cases were reported in Central and South America, resulting in two deaths, one miscarriage, and four newborns with birth defects.
Earlier this month, nineteen cases were reported in Europe, prompting an alert from the European Centre for Disease Control.
The Oropouche virus is spread by mosquitoes and a small blood-sucking insect called the midge.
Despite its nickname, sloth fever is not caused by contact with sloths.
Instead, it was given the nickname because scientists believe sloths can carry and be infected with the disease. Experts suspect that other animals, such as birds, can also carry the virus.
If you are bitten by an insect carrying Oropouche, there are no medications to treat it and no vaccines to prevent it. The only defense against the disease is to not get bitten at all when traveling to these regions.
The 21 infected Americans ranged in age from 15 to 94, with an average age of 48. The most common symptom was fever (95 percent), followed by muscle aches (86 percent), headache (76 percent), fatigue (62 percent) and joint stiffness (57 percent).
Patients also reported diarrhea, abdominal pain, nausea, vomiting, rash, back pain, and bloody mucus.
Fewer than one in twenty people who get the disease develop more serious, life-threatening symptoms. These include severe bleeding, meningitis, a swelling of the membranes that protect the brain, and encephalitis, a swelling of the brain itself.
It can also cause birth defects and miscarriages.
It is unclear whether any patients in the CDC report were pregnant. Pregnancy status was not collected for confidentiality reasons.
The agency advised doctors to report suspected Oropouche infections to state or local health authorities to expedite testing and prevent spread. Patients should avoid taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen to reduce the risk of bleeding.
To prevent infection, the CDC recommends wearing long sleeves and pants, using insect repellent, and staying in areas with screens on windows and doors.