sloth fever virus oropo virus sloth fever is a viral illness caused by the orpo virus the virus is transmitted to humans through the bites of infected mosquitoes and midges while it's named sloth fever sloths are not the primary reservoir for the virus instead it's believed to circulate among various animals including Birds rodents and possibly sloths symptoms of sloth fever can vary but often include fever headache muscle aches joint pain nausea and vomiting rash the focus is on managing symptoms and providing supportive care if you're experiencing symptoms consistent with SLO fever it's important to seek medical attention avoid mosquito bites wear long- sleev clothing and pants use insect repellent and stay indoors during Peak mosquito activity hours if you have concerns about your risk of slow fever consult with a health care provider for personalized advice