What is the ‘Sloth Fever Virus’?
The Oropouche virus, commonly referred to as “sloth fever,” is an emerging insect-borne virus that has recently raised alarms among health officials. This virus, primarily spread by tiny biting insects known as midges and some mosquitoes, was first identified in Trinidad and Tobago in 1955. While originally confined to the Amazon basin and tropical forest areas, recent outbreaks have occurred in new regions, including the Caribbean and South America. Notably, 21 cases have been reported among U.S. travelers returning from Cuba, prompting the Centers for Disease Control and Prevention (CDC) to issue a warning.
How is it Spread?
Sloth fever, or the Oropouche virus, is named after its early detection in a sloth in Brazil. Contrary to what its name suggests, the virus is not spread by sloths. Instead, it is transmitted to humans by tiny biting insects, primarily midges, which are often referred to as “no-see-ums,” and some mosquito species that also carry viruses like West Nile. The virus’s ability to spread from insects to humans in forested areas and subsequently into urban environments has made it a significant public health concern.
Sloth Fever Virus Symptoms and Risks
Symptoms of Sloth Fever Virus:
Symptoms of the sloth fever virus are often similar to those of other tropical diseases such as dengue and Zika. Common symptoms include:
- Fever
- Chills
- Headache
- Muscle and joint pain
- Rash
- Nausea and vomiting
- Diarrhea
While most cases are mild, some individuals may experience severe symptoms, including meningitis (inflammation of the membranes surrounding the brain and spinal cord) and encephalitis (inflammation of the brain). Unique to the Oropouche virus, some patients report a recurrence of symptoms after initially recovering, a phenomenon not typically observed in similar arboviral diseases.
Recent Pandemic Outbreaks
From January 1 to August 1, 2024, more than 8,000 cases of the Oropouche virus were reported in Brazil, Bolivia, Peru, Colombia, and Cuba. In these recent outbreaks, two fatalities were documented, alongside five instances of vertical transmission (mother-to-child transmission in utero), which can lead to fetal death or congenital abnormalities. These developments have heightened concerns about the virus’s potential impact on human health.
In the U.S., the CDC has identified 21 cases of sloth fever among travelers returning from Cuba, with 20 cases in Florida and one in New York. No local transmission of the virus has been reported within the U.S. or its territories. However, health officials are on high alert, especially since some of the U.S. patients experienced recurrent symptoms after their initial recovery.
Prevention and Recommendations
How to Prevent Sloth Fever Virus:
Currently, there are no vaccines available to prevent Oropouche virus infection, nor are there specific medications to treat it. The best method of prevention is avoiding insect bites by:
- Using Environmental Protection Agency (EPA)-registered insect repellents.
- Installing effective window and door screens.
- Using fans when outdoors to help blow biting insects away.
Recommendations for Travelers:
Given the risk of infection, especially for pregnant women, the CDC advises reconsidering non-essential travel to Cuba and other affected areas. Travelers should take precautionary steps to avoid insect bites and discuss any potential risks with their healthcare providers.
What is Being Done for Public Health?
The emergence and spread of the sloth fever virus in areas previously unaffected have prompted a coordinated response from global health organizations. The CDC, in collaboration with state health departments and international partners, is enhancing surveillance and diagnostic testing to monitor the virus’s spread and to facilitate rapid response measures. The agency is also providing updated travel advisories and recommendations to minimize the risk of further transmission.
Clinicians and public health authorities in the U.S. are urged to consider Oropouche virus testing for patients presenting symptoms consistent with the virus and who have recently traveled to affected areas. Increased vigilance and preventive measures are crucial to mitigate the potential impact of this emerging health threat.
As the situation evolves, we’ll keep you informed and vigilant, it is currently the best way to prevent further spread and mitigate the impact of sloth fever in the U.S. and beyond.
