Federal health officials announced on Tuesday that over 20 individuals returning to the United States from Cuba have contracted Oropouche virus disease, commonly referred to as sloth fever, in recent months. Fortunately, no fatalities have occurred, and there is currently no evidence of the virus spreading within the U.S. However, officials are advising doctors to remain vigilant for cases among travelers returning from Cuba and South America.
Oropouche virus is indigenous to wooded tropical regions and was first discovered in 1955 when it infected a forest worker in Trinidad. Its name is derived from a nearby village and wetland. The virus earned the nickname “sloth fever” because initial research linked it to infections found in three-toed sloths, suggesting their role in transmitting the virus through insect vectors.
The transmission of Oropouche virus occurs primarily through small biting flies known as midges, as well as certain types of mosquitoes. Infections are associated with visits to forested landscapes, and while humans can introduce the virus into urban settings, person-to-person transmission has not been documented.
Recent outbreaks of the virus have been reported since late last year across Amazon regions and some new areas in South America and the Caribbean, resulting in approximately 8,000 locally acquired cases in Bolivia, Brazil, Colombia, Cuba, and Peru. In the United States, the Centers for Disease Control and Prevention (CDC) identified 21 cases so far—20 in Florida and one in New York—following travel to Cuba. European health authorities have reported 19 cases, mostly among travelers.
Symptoms associated with Oropouche virus can resemble those of other tropical diseases such as dengue, Zika, and malaria, including fever, headaches, and muscle aches. Additional symptoms may include diarrhea, nausea, vomiting, and rashes. Some individuals experience recurring symptoms, with about 5% of cases leading to more severe complications, such as bleeding, meningitis, and encephalitis. While rare, recent reports indicate that two healthy young individuals in Brazil have died from the virus.
Currently, there are no vaccines available to prevent Oropouche virus infections, nor are there specific treatments for the symptoms. The investigation into possible transmission from pregnant women to their fetuses is ongoing in Brazil, raising concerns reminiscent of the Zika virus outbreaks several years ago.
To mitigate risks, the CDC advises pregnant women to avoid non-essential travel to Cuba and encourages all travelers to take preventive measures against insect bites by using repellents and wearing long-sleeved clothing.