None of the travelers have died, and there is no evidence that the virus is spreading in the United States. However, officials are recommending that U.S. doctors be alert to the infection in travelers from Cuba and South America.
Here’s a look at the disease and what triggered the alert.
What is Oropouche virus?
Oropouche is a virus native to tropical forested areas. It was first identified in 1955 in a 24-year-old forest worker on the island of Trinidad, and was named after a nearby village and wetlands.
It was sometimes called “sloth fever” because scientists who began studying the virus discovered it in a three-toed sloth and thought that sloths played a significant role in its spread between insects and animals.
How is the Oropouche virus spread?
The virus is transmitted to humans by small, biting flies called midges and some types of mosquitoes. Humans have been infected while visiting forested areas and are thought to have contributed to the spread of the virus in cities, but person-to-person transmission has not been documented.
How many cases have been recorded?
Starting late last year, the virus was identified as causing major outbreaks in Amazon regions where it was known to exist, as well as in new areas of South America and the Caribbean. About 8,000 cases of local infection have been reported in Bolivia, Brazil, Colombia, Cuba and Peru.
Some travelers have been diagnosed in the United States and Europe. The U.S. Centers for Disease Control and Prevention said Tuesday that 21 U.S. cases had been reported so far — 20 in Florida and one in New York — and all had been to Cuba. European health officials had previously said they had found 19 cases, almost all in travelers.
What are the symptoms and treatments?
Symptoms can be similar to those of other tropical diseases such as dengue fever, Zika, or malaria. Fever, headache, and muscle aches are common, and some infected people also experience diarrhea, nausea, vomiting, or a rash.
Some patients have recurring symptoms, and 1 in 20 people may have more serious symptoms such as bleeding, meningitis or encephalitis. The infection is rarely fatal, although two healthy young people have recently died in Brazil.
There are no vaccines to prevent infections and no medications to treat symptoms.
Are there any other concerns?
In Brazil, authorities are investigating reports that infections could be transmitted from a pregnant woman to a fetus — a potentially frightening echo of what was seen during Zika outbreaks nearly a decade ago.
The CDC has recommended that pregnant women avoid all nonessential travel to Cuba and suggested that all travelers take steps to avoid insect bites, such as using insect repellent and wearing long-sleeved shirts and long pants.