A virus found in sloths and spread by mosquitos in South America has now been found in the US.
The US Centers for Disease Control (CDC) issued has issued a warning about the Oropouche virus after 11 Floridians returned from summer travel with the disease.
The condition is spread by mosquitos in tropical parts of the Caribbean and South America, and causes fever, rash, joint aches.
In rare cases, it can cause brain swelling and death, and claimed the life of two healthy Brazilian women earlier this year.
In 2024, there have been more than 8,000 cases reported in Central and South America – causing two deaths, one miscarriage and four newborns to be born with birth defects. Nineteen cases were reported in Europe earlier this month, leading to a warning from the European Center for Disease Control.
The Oropouche virus is nicknamed sloth fever not because it’s transmitted by sloths, but because the animals can be carriers for the disease
The Oropouche virus is spread primarily by bites from a bug called a midge. Sometimes, mosquitos also carry it
The US CDC’s warning was specifically addressed to doctors and public health authorities, asking them to test people who’ve returned from a Latin American vacation this summer for the virus.
The Oropouche virus is spread by mosquitos and a bug called a midge – which is a small, blood sucking winged insect.
Despite it’s nickname, sloth fever is not caused by coming into contact with sloths.
Instead, it got the nickname because scientists believe sloths can carry and be infected by the disease. Experts suspect other animals, like birds, can also carry the virus.
If you get bit by a bug carrying Oropouche, there are no medicines to treat it and no vaccines to prevent it. The only defense against the disease is to avoid being bit all together when travelling to these regions.
The CDC recommends wearing long sleeves and pants, wearing insect repellant and staying in places that use window and door screens.
Common symptoms include fever, severe headache, chills, muscle ache and joint pain, according to the CDC.
Less than one in 20 people who get the disease will go on to develop more serious, life threatening symptoms. These include severe bleeding, meningitis, a swelling of the membranes that protect the brain, and encephalitis, a swelling of the brain itself.
It can also cause birth defects and miscarriage.
The four babies reported in the CDC’s letter were born with microcephaly – a condition where the brain and skull of a newborn is much smaller than it should be.
As such, the CDC letter urged pregnant women to reconsider potential travel plans to the area.
Aside from transmission during pregnancy, the virus cannot spread between humans.
Cases have been reported in Brazil, Bolivia, Peru, Colombia and Cuba. All cases reported in Europe and North America have been in people who have recently travelled to one of those countries.
Medical entomologists Cameron Webb, from the University of Sydney and Andrew van den Hurk Medical from The University of Queensland, said this has been a local concern for years, but it’s the first time it’s drawing international attention.
‘The situation is reminiscent of the Zika outbreak in 2015–16,’ Professor Webb and Professor van den Hurk said.
Dr Danny Altmann, a professor of Immunology at Imperial College London, told The Telegraph: ‘we should all be worried’.
He added: ‘Oropouche is certainly a worry for its uncertainty and, for all those worried about global health, it just feels like climate change is adding to the healthcare burden in a very palpable way, season by season’.
Rachel Carter is a health and wellness expert dedicated to helping readers lead healthier lives. With a background in nutrition, she offers evidence-based advice on fitness, nutrition, and mental well-being.
