. >> Right now at 530. >> Health alert a new mosquito borne virus is spreading in the U.S. Almost two dozen people returning from Cuba have been infected by what is known as sloth fever. >> And health officials are now warning doctors to be on the lookout for this infection in avelers especially. But what are the symptoms of sloth fever ? Well, for that, we're going to turn to local Ten's Layron Livingston. He is live in Miami with everything you need to know. Lauren fill us in. >> Listen, there's a lot going on, especially here in South Florida, where we already have experienced West Nile and dengue and Zika. And now we have this illness to concern ourselves with sloth fever or sloth flu is what it's sometimes called. Decades ago, researchers first investigating the virus found it in a sloth, and it was thought te disease, as you might have gotten it from a sloth that had been bitten by a midge. >> You might not have. You might have gotten it from a midge, had bitten somebody else. Know sloth involved? >> More than likely it was the midge or mosquito doing what they do and spreading the illness. >> People get a rapid onset of fever, headache? >> Um, your joints get stiff, you get aches and pains. Uh, a lot of people will have a rash, infectious disease specialist Doctor Eileen Marty says in most cases, though, there are no symptoms, meing folks may not even know they're infected. >> This week, the CDC reported 21 US cases of Oropouche virus. That's the official name. One case in New York, 20 cases in Florida. >> These are the ones detected, not necessarily all the ones that may or may not have come to the United States. >> The CDC says all those people had traveled to Cuba. >> They're going to come back from wherever they acquired the virus with virus in their blood. >> For our midges and mosquitoes to get infected. >> And that's what we need to prevent. >> There's no vaccine for sloth d preventable. Doctor Marty says that's where mosquito control measures come into play, like repellents. >> You should be prudent, right? >> You should know where you are . Know where you are, and take the necessary precautions. >> Now, there have been deaths reported in other parts of the world, Latin America, but thankfully here in the United States, there have been no deaths reported. As it relates to this illness. And there's also right now, no evidence that it is actually spreading, as in, nobody has been bitten by a mosquito that had it and then transmitted the disease to another person who did not. Of course, it's something that health officials say we need to be aware of and on alert for. We're here in Miami