The US Centers for Disease Control and Prevention (CDC) has issued a warning about the rise in Oropouche virus disease cases in the Americas, with cases also reported in Europe.

In June and July of this year, 19 cases of Oropouche virus disease, also referred to as “sloth fever,” were reported for the first time in European countries.

All of the travellers who returned to Europe with symptoms had been to Cuba or Brazil.

Read on for what travellers need to know about this deadly disease and how to stay safe.

Where are travellers catching Oropuche virus?

Beginning late last year, the virus was identified as the cause of large outbreaks in Amazon regions where it was known to exist, as well as in new areas in South America and the Caribbean.

About 8,000 locally acquired cases have been reported in Bolivia, Brazil, Colombia, Cuba, and Peru.

As of August, 19 cases have been reported in European countries: 12 in Spain, five in Italy and two in Germany. Eighteen of the cases had travelled to Cuba and one to Brazil, according to the European Centre for Disease Prevention and Control.

Oropouche is a virus that is native to forested tropical areas. It was first identified in 1955 in a 24-year-old forest worker on the island of Trinidad, and was named for a nearby village and wetlands.

It has sometimes been called sloth fever because scientists first investigating the virus found it in a three-toed sloth, and believed sloths were important in its spread between insects and animals.

The symptoms of Oropouche are similar to those of dengue, Zika and malaria.

What are the symptoms and treatments for Oropouche?

Symptoms can seem similar to other tropical diseases like dengue, Zika or malaria.

After an incubation period of 3–10 days, patients typically experience abrupt onset of fever, chills, headache, myalgia, and arthralgia. Other symptoms might include retroorbital pain, photophobia, vomiting, diarrhea, fatigue, maculopapular rash, conjunctival injection, and abdominal pain, according to the CDC.

Most people recover from Oropouche though some suffer recurring symptoms, and one in 20 can suffer more severe symptoms like bleeding, meningitis and encephalitis. It is rarely fatal, though there are recent reports of deaths in two healthy young people in Brazil.

There are no vaccines to prevent infections and no medicines currently available to treat the symptoms.

Who is most at risk from Oropouche?

In Brazil, officials are investigating reports that infections might be passed on from a pregnant woman to a fetus – a potentially frightening echo of what was seen during Zika outbreaks nearly a decade ago.

The CDC has recommended that pregnant women avoid non-essential travel to Cuba and suggested all travelers take steps to prevent bug bites, such as using insect repellents and wearing long-sleeved shirts and long trousers.

How does Oropouche virus spread?

The virus is spread to humans by small biting flies called midges, and by some types of mosquitoes. Humans have become infected while visiting forested areas and are believed to be responsible for helping the virus make its way to towns and cities, but person-to-person transmission hasn’t been documented.

How many cases have there been?

19 cases have been found in Europe, though this is nothing compared to the 8,000 identified cases in the Americas.

21 people returning to the US from Cuba have been infected with the virus – 20 were in Florida and one was in New York. They had all been to Cuba

Concerns are growing over the rise of West Nile virus after it killed two more people in Seville, Spain, raising the country’s total to five deaths this year.

Travellers and locals alike have been advised to wear insect repellant, cover up, and avoid breeding grounds like stagnant water – particularly between dusk and dawn.

This year in Europe, cases also have been reported in Austria, Croatia, France, Greece, Hungary, Italy, Romania and Serbia. These were confirmed by the European Centre for Disease Prevention and Control (ECDC) as having been acquired locally rather than on trips to tropical regions.

It comes after dengue fever outbreaks in Europe put travellers on red alert in spring.

What is West Nile virus and what are the symptoms?

West Nile virus (WNV) can cause a fatal neurological disease in humans. It belongs to the Japanese encephalitis group of viruses, along with others like dengue and yellow fever.

Birds are the natural hosts of WNV, but it is typically spread by mosquitoes and, in a small number of cases, through blood transfusion, organ donations or pregnancy.

In around four out of five patients, WNV presents no symptoms, but in the other 20 per cent, it develops into West Nile fever. Symptoms include sudden high fever, headache, neck stiffness and a rash on the neck, arms, or legs – and in more severe cases, seizures, muscle weakness and paralysis, according to ECDC.

People over the age of 50 – especially if they have underlying health conditions – are more likely to get seriously ill. Less than 1 per cent of people go on to develop neurological infections such as meningitis or encephalitis – with one in 10 of these cases being fatal.

Symptoms typically appear two to six days after infection but can take up to 14 days or more to develop. In uncomplicated cases, these usually ease within three to six days.

How to protect yourself against West Nile virus

No vaccine against WNV is yet available for humans, so the best way to protect yourself is to prevent mosquito bites.

You can do this by not travelling to affected areas at times when mosquitoes are more common, such as in summer, and reducing your time outdoors when in an affected area.

The virus was first detected in the West Nile district of Uganda in 1937, but can now be found in countries across the world, including in Africa, the Middle East, west and central Asia, North America – and Europe.

Using mosquito repellant, covering your arms, legs and feet, and keeping mosquitoes out of your bedroom at night can also help prevent infection.

If you feel unwell – especially if you have a fever – you should contact your doctor and tell them where you have recently travelled to.

Why is Europe seeing more cases of mosquito-borne illness?

Record-high temperatures and other extreme weather events driven by climate change are causing an uptick in virus outbreaks in Europe.

“Europe is already seeing how climate change is creating more favourable conditions for invasive mosquitoes to spread into previously unaffected areas and infect more people with diseases such as dengue,” ECDC’s director Andrea Ammon said in June.

“Increased international travel from dengue-endemic countries will also increase the risk of imported cases, and inevitably also the risk of local outbreaks,” she added.

Locally acquired dengue cases in Europe almost doubled between 2022 and 2023, and figures suggest it could become even more prevalent this year.

Where are infections most likely in Europe?

Dengue-carrying tiger mosquitoes are now established in 13 European countries: Austria, Bulgaria, Croatia, France, Germany, Greece, Hungary, Italy, Malta, Portugal, Romania, Slovenia and Spain.

The first large outbreak of WNV in Europe occurred in Romania in 1996. Cases have since been identified in European countries including Austria, Croatia, France, Greece, Hungary, Italy, Portugal, Romania, Serbia and Spain.

Recently, WNV carrying mosquitos have been detected in towns near Spain’s Guadalquivir River, such as Coria del Rio near Seville. Various regions in Greece have also been affected, including Kos, Thessaloniki and Zakynthos, as well as Italy including Bologna, Modena, Salerno and Venice, among others.

In 2023, 713 locally acquired cases were reported in the EU/EEA in 123 different regions – 22 of which were seeing the infection for the first time. Tragically, 67 deaths were reported.

The case seen in Spain in March this year came unusually early, likely due to unseasonably warm weather.

ECDC warns that the mosquito responsible for transmitting dengue and Zika virus is spreading further north, east and west in Europe, and has recently established itself in Cyprus.

Driving between France and Italy this year? You may be forced take a detour as the Mont-Blanc Tunnel, which links the two countries beneath the Alps, is closing for 15 weeks for renovation work.

Between 2 September and 16 December, a 600-metre stretch of the 11-kilometre tunnel will be completely reconstructed. During this time, the Tunnel du Mont-Blanc will be closed to traffic.

Alternative routes are available but they will likely add to your travel time. Here’s how to plan your Europe road trip around this autumn’s closure.

Why is the Mont-Blanc Tunnel closing?

Opened in 1965, the Mont-Blanc highway tunnel links Chamonix in Haute Savoie, southeast France, with Courmayer in Aosta Valley, northwest Italy.

It is part of the north-south European route E25, which runs from the Hook of Holland down to the ferry crossing from Cagliari to Palermo in Sicily.

Lying 2,480 metres beneath the Aiguille du Midi summit, it is the world’s second deepest tunnel in operation after Switzerland’s Gotthard Base Tunnel.

Various closures have taken place throughout 2024 to allow for maintenance work, safety drills and renovation.

This autumn’s closure is scheduled for structural renovation work on the vault. It will be one of the first major European tunnels to undertake deep renovation work on its structure.

Between 5pm on 2 September and 5pm on 16 December, different reconstruction technologies will be tested on two 300 metre stretches of the tunnel.

The most efficient and effective techniques could then be applied to an additional 600 metre section during another closure in 2025 – and further works along the tunnel’s entire length in the coming years.

During the Mont-Blanc Tunnel closure, it will still be possible to drive between France and Italy on different routes.

Although these may extend your journey time, they could save you money: the one-way toll for a car use to the Mont-Blanc tunnel is €51.50 while a return is €64.20.

Around 160 km south of the Mont-Blanc Tunnel, the Fréjus Tunnel connects Modane in France to Bardonecchia in Italy. It is slightly cheaper to use, with a one-way trip for cars costing €47 and a return €57. Heavy goods vehicles will be diverted to this route during the closure.

Toll payment subscriptions including the TMB card and Eurotoll cover both tunnels under the same pass. Multi-journey discount passes valid during the Mont-Blanc Tunnel closure will automatically be extended by four months.

Alternatively, the Tunnel du Grand-Saint-Bernard links Martigny in Valais, Switzerland, with Saint-Rhémy-en-Bosses in Italy’s Aosta Valley. The one-way toll for a car is €31.

Located further southwest, the Col du Petit-Saint-Bernard is a mountain pass linking Savoie in France with Aosta Valley. However, it could face closures due to heavy snow, so check the weather before planning your route.

To the north, the Col des Montets mountain pass, linking Chamonix with Vallorcine in France – on the border with Valais – is another route that could be hit by snow closures.

The Tunnel des Montets, a single track railway tunnel that doubles as a road, can sometimes be used when the pass is closed but it is likely to face heavy traffic.

The scenic Mont Cenis pass between the Cottian Alps in France and the Graian Alps in Italy is typically open to traffic until November, when it closes for the winter season.

The Montgenèvre Pass connecting Briançon in France and Cesana Torinese in Italy is another option for road travel further south of the Tunnel du Mont-Blanc.