COLUMBIA, Mo. – If winter travels are in your plans, you might bring back more than just a sunburn and souvenirs.

Emily Althoff, extension urban entomologist for the University of Missouri and Lincoln University, says travelers who become ill after visiting South and Central America should let their doctors know their travel history.

The Pan American Health Organization recently upgraded the risk of Oropouche virus disease, commonly called sloth fever, from moderate to high.

The main concern is that the primary vector of the disease is also native in North America, Althoff says. Localized outbreaks could occur if humans who contracted OROV elsewhere are bitten by the vector. Historically, the disease is primarily transmitted from a biting midge native to the Americas. It also spreads through the southern house mosquito.

Doctors diagnosed the first local infections in June 2024. Twenty Floridians and one New Yorker who visited Cuba were infected. Doctors also confirmed an additional case in Kentucky. Authorities reported fatalities in two healthy individuals in Brazil this year.

The disease is not new: It was first identified in 1955 in Trinidad and Tobago, says Althoff, and there have been sporadic outbreaks in Brazil, Panama and Peru over the years. The disease is of special concern to pregnant women because of potential associations with fetal death.

Althoff says experts are unsure whether there are more infections now than earlier or if researchers and professionals have better tools for diagnosis at their disposal.

The numbers are low now, says Althoff, but it is important to be aware of symptoms and report them to your doctor right away. “It is critical to monitor your health after traveling to potential hot spots,” she says.

Symptoms include fever, headache and chills 3-10 days after infection. Infected humans may also experience light sensitivity, disorientation, eye pain, nausea, vomiting or maculopapular rash. Less common symptoms include inflamed or dilated blood vessels of the eye, diarrhea, severe abdominal pain and bleeding. In less than 4% of patients, neurological symptoms may appear.

Symptoms often reappear after treatment and are often mistaken for other diseases, including malaria. There are no vaccines to prevent or treat Oropouche virus disease, so the best protective measure is using an EPA-registered insect repellent and wearing long sleeves and pants to prevent bites.

For more information

“Clinical Overview of Oropouche Virus Disease,” https://cdc.gov/oropouche/hcp/clinical-overview

“Health Advisory: Increased Oropouche Virus Activity and Associated Risk to Travelers,” https://health.mo.gov/emergencies/ert/alertsadvisories/pdf/cdc-advisory081624.pdf

Photo

https://phil.cdc.gov/details.aspx?pid=17697

The southern house mosquito can transmit Oropouche virus disease, also known as sloth fever. Public domain photo by James Gathany/Centers for Disease Control and Prevention.