U.S. health authorities are cautioning travelers about a potentially lethal insect-borne virus referred to as sloth fever, which has infected 21 individuals returning from Cuba, alongside thousands more in South America and the Caribbean.
As of August 1, more than 8,000 cases of Oropouche virus disease have been documented in Brazil, Bolivia, Peru, Colombia, and Cuba. Additional cases have emerged in the U.S. and Europe among travelers returning from Cuba and Brazil, according to a report from the Centers for Disease Control and Prevention (CDC).
Sloth fever is an informal term for infections caused by the Oropouche virus, first identified in Trinidad and Tobago in 1955. The virus is transmitted through bites from midges and mosquitoes and is commonly found in central and eastern South America.
The current outbreak has seen cases in Brazil, Bolivia, Peru, Colombia, and Cuba, with U.S. infections occurring among travelers returning to Florida and New York from Cuba. While commonly referred to as sloth fever, the Oropouche virus can also infect rodents, monkeys, and birds.
Symptoms of sloth fever tend to be mild; however, two healthy women in Brazil, aged 24 and 21, have died after contracting the virus. Symptoms typically appear three to ten days post-infection and include fever, chills, headaches, and muscle and joint pain or stiffness. Other possible symptoms comprise vomiting, diarrhea, fatigue, skin rash, abdominal pain, sensitivity to light, and eye redness. Treatment focuses on alleviating symptoms through rest, fluids, and acetaminophen for fever and pain relief.
Public health officials express particular concern over cases of mother-to-fetus transmission.
Currently, there is no vaccine or antiviral treatment available for Oropouche virus.
The CDC has identified five cases where an infected mother seemed to transmit the virus to her fetus. Sadly, one fetus died, and four reported microcephaly, a defect characterized by an unusually small head. The CDC emphasized that these incidents indicate a possible link between the virus and both fetal death and congenital malformations, raising alarms about the health risks associated with Oropouche virus.
For pregnant individuals contemplating travel, the CDC suggests they consult healthcare providers about potential risks before visiting areas with known outbreaks. Pregnant travelers should take precautions to avoid insect bites and may want to postpone travel to regions experiencing sloth fever outbreaks.
In the U.S., 20 confirmed cases were reported among Florida residents and one in a New York resident returning from Cuba. Most patients received medical evaluation upon falling ill; however, three experienced recurring symptoms. The median age of affected patients was 48, with common symptoms including fever, muscle pain, headaches, fatigue, and joint pain or stiffness. Some patients also reported symptoms such as diarrhea, abdominal pain, nausea, vomiting, rash, back pain, and bleeding.