Oropouche virus – or sloth fever, as it’s also known – is a deadly virus that’s quietly spreading across South America and Europe, and scientists fear it’s more prevalent than first believed
Oropouche virus is far more common and dangerous than previously believed, scientists have revealed.
The virus – which is also known as sloth fever – has soared across South America over the past 18 months, and it’s recently been discovered in Europe for the first time, too. It’s spread by midges and some types of mosquito, and it’s largely contained the Amazon region.
Sloth fever was largely believed to be a mild infection, with general symptoms like headaches, rashes and nausea. But, it could also lead to pregnancy loss or birth defects, scientists warned.
More than 20,000 cases of oropouche virus have been reported in Latin America since late 2023, sparked by a warming climate and more frequent rain storms. Anyone living around the Amazon rainforest was most at risk of infection, with analysis showing up to 10% of all people had previously had sloth fever – whether they knew it or not.
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“We therefore assume that the current oropouche outbreak has been fueled by weather phenomenons like El Niño,” explains Professor Jan Felix Drexler, head of the Virus Epidemiology laboratory at the Institute of Virology at Charité. El Niño describes a weather phenomenon that causes a higher-than-average sea surface temperature in the central Pacific Ocean.
“By contrast, we have not found evidence that changing properties of the virus could provide an alternative explanation for the high case count at present,” he added
Professor Drexler also sent an ominous warning for the rest of the world, claiming the virus could spread even further outside the continent.
“I think it’s possible that oropouche virus will become even more widespread in the future as climate change progresses.”
Sloth fever was found in Europe for the very first time last year. It was confirmed in Italy, Spain and Germany. Spain reported 12 cases of oropouche in June and July of 2024. Italy had five cases, and Germany had two.
Eighteen of the 19 cases had a travel history to Cuba, and one had previously visited Brazil. It’s not believed any of the cases were internally passed on in Europe, and they all picked up the virus outside the continent.
Oropouche was first discovered in 1955, in Trinidad and Tobago. It got its name after being found next to the Oropouche River. The virus has previously sparked outbreaks in Brazil, Bolivia, Colombia, Ecuador, French Guiana, Panama, and Peru over the past 25 years.
In June last year, Cuba reported its first case of the infection. Sloth fever symptoms tend to start somewhere between three and 10 days after infection, according to the Centers for Disease Control and Prevention (CDC). There have been very few deaths among people infected with the virus, it added.
There’s no current medication to treat oropouche, and there’s no vaccination to protect against it. Anyone that’s been diagnosed with the infection would be advised to get plenty of rest and drink lots of fluids.
There have been no confirmed cases of sloth fever in the UK, and the risk of it ever reaching Britain or Northern Ireland remains incredibly low. But, it’s vital that everyone stays alert to the threat, and seeks medical attention if they think they could be at risk, health experts have claimed.
Dr Philip Veal, Travel Health Consultant at UKHSA, said: “The midge that carries Oropouche virus is not currently established in Europe. It is typically found in the Americas. There is no evidence that the virus can spread from person to person.
“When travelling to affected areas, you can avoid the infection, and others such as dengue, Zika and malaria, by preventing insect bites. Use insect repellent, cover exposed skin and sleep under a treated bed net. Plan ahead and visit the TravelHealthPro website to look up your destination and the latest health information and advice, particularly if you are pregnant.”