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Evening Standard
Evening Standard
World
Sian Baldwin and Nuray Bulbul

What is the sloth fever? Symptoms of virus that is spreading across Europe and the US

A rare virus, referred to as sloth fever, was detected in 21 travellers who were returning from Cuba to the US, according to the Centres for Disease Control and Prevention (CDC).

One case in New York and 20 cases in Florida have been reported as of Tuesday, August 27.The majority of individuals who came back from Cuba with symptoms were recorded between May and July.According to the CDC's Morbidity and Mortality Weekly Report, three individuals were admitted to the hospital overall, but no deaths were noted.

The disease, which health experts have warned could be “unstoppable”, was called sloth fever after it was found in sloths based in South America.

Dubbed a “mysterious threat” in the Lancet journal, little is known about it as it is still an emerging disease, but world health experts have warned people to be wary of symptoms – particularly if you are pregnant.

The virus, formally known as oropouche fever, has already reportedly killed two in Brazil last month, both women in their twenties, and now it has already reportedly made its way to Europe.

It is believed it is spread by mosquitoes and midges.

So far, more than 10,000 cases have been reported this year, 19 of which have been in Europe - with 12 in Spain, five in Italy and two in Germany.

It is believed all of the cases in Europe affect people who have recently travelled to areas where the virus is already established, and there has not yet been any case of human-to-human transmission detected.

Here is what we know.

What is sloth virus?

Mainly spread by midges and mosquitoes, there is no known vaccine or cure for this neurotropic virus at present, and typical prevention methods, such as using nets to sleep under, may not be effective as the midges are so small.

It is a virus that affects people after they are bitten by insects that have fed on sloth, monkey or bird blood, and is said to be similar to dengue fever.

There have been numerous reported cases in South America and Cuba, leading health professionals to warn those travelling to those areas to beware.

What symptoms does sloth virus cause?

One of the main symptoms is fever but other symptoms include headache, muscle aches, stiff joints, nausea, vomiting, chills, and sensitivity to light. You do not have to have all of the symptoms to have the virus. Rarely, it can cause meningitis and encephalitis.

Most people recover with no lasting effects, but there are fears the virus could be dangerous to unborn babies, potentially causing stillbirth, miscarriage or deformities in the foetus.

Symptoms typically start four to eight days after being bitten and last three to six days.

Is there a cure for sloth virus?

At present, no. It is an emerging virus, which means not a lot is known about it.

There is no specific medicine available to cure it, and patients can only be given supportive treatment to treat the symptoms.

Although most will fully recover, health experts are warning that because not a lot is known, caution must be used when travelling to areas where cases are present.

The US-based Centers for Disease Control and Prevention (CDC) has warned that severe cases may result in neuroinvasive diseases such as meningitis and, on July 17, an alert was given by the UN about possible negative health effects to unborn babies if the mother contracts the disease while pregnant. Potential cases of pregnant mother-to-child transmission in Brazil are being looked into. 

Among the cases under investigation are four newborns with microcephaly (a smaller than normal head) found to have antibodies against oropouche virus in serum samples, though they tested negative for other viruses, such as zika, known to affect foetuses.

Another case is of a woman who suffered a stillbirth in June this year, having contracted the oropouche virus, and another who miscarried.

Should we be worried?

The disease, which was first detected in 1955, is now spreading fast due to travel, climate change, and deforestation, while also mutating to overcome our immune systems.Dr Paul Hunter, a professor of medicine at the University of East Anglia, told the Telegraph that he would advise “against non-essential travel to infected areas for pregnant women”.

He added that he is “almost certain” that in Europe there are more infections than have yet been detected and reported. 

Others have said there is a real need for vigilance, and to seek medical help should you contract any of the symptoms after travelling to countries where the virus is known to be. So far, there are no known cases in the UK.

Dr Danny Altmann, a professor of immunology at Imperial College London, told the Metro that the virus was “taking off this summer in the Americas”, meaning tourists should be aware. 

He said: “Southern Europe and North America could one day be much more at risk from diseases such as sloth fever and zika because global warming is allowing the midges and mosquitoes that spread them to expand the areas they can thrive.”

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