What to know about the Oropouche virus, also known as sloth fever

HAVANA (AP) — More than 20 people returning to the U.S. from Cuba have been infected with a virus transmitted by bugs in recent months, federal health officials said Tuesday. They all had Oropouche virus disease, also known as sloth fever.

None have died, and there is no evidence that it’s spreading in the United States. But officials are warning U.S. doctors to be on the lookout for the infection in travelers coming from Cuba and South America.

Here’s a look at the illness and what sparked the alert:

What is Oropouche virus?

Oropouche is a virus that is native to forested tropical areas. It was first identified in 1955 in a 24-year-old forest worker on the island of Trinidad, and was named for a nearby village and wetlands. It has sometimes been called sloth fever because scientists first investigating the virus found it in a three-toed sloth, and believed sloths were important in its spread between insects and animals.

How does Oropouche virus spread?

The virus is spread to humans by small biting flies called midges, and by some types of mosquitoes. Humans have become infected while visiting forested areas and are believed to be responsible for helping the virus make its way to towns and cities, but person-to-person transmission hasn’t been documented.