What is sloth fever and can I catch it?

An emerging virus dubbed ‘sloth fever’ has caused some alarm, after the European Centre for Disease Prevention and Control reported that 19 imported cases of the disease have been found in the European Union for the first time.

The oropouche virus (OROV), an RNA arbovirus, was first detected in the village of Oropouche in Trinidad and Tobago in 1955.

It’s spread to people primarily through the bite of infected biting midges, according to the London School of Hygiene and Tropical Medicine. Some mosquitoes have also been known to carry the virus.

The Pan American Health Organisation (PAHO) first issued an epidemiological alert about an increase in reported cases of the virus in five countries – Brazil, Bolivia, Peru, Cuba and Colombia- in July.

Why is it called sloth fever?

The Lancet medical journal reported that the virus has a reservoir in pale-throated sloths, but also non-human primates and birds. Nonetheless the possible link to sloths seems to have caught on.

“The term ‘sloth fever’ is a colloquial name that has emerged due to the virus being found in areas where sloths, which are known to carry a range of parasites and pathogens, are present,” explained Carolina Goncalves, superintendent pharmacist at Pharmica. “However, the name is relatively misleading as it is spread by insect bites, not by direct contact with sloths.”

Why has it happened?

Dr Enny Paixao, associate professor at the London School of Hygiene and Tropical Medicine, said: “Several factors may explain the recent outbreak, including enhanced surveillance, climate and environmental changes, and potential changes to the virus.

“Similarly to other vector-borne diseases, such as dengue, climate change may also be impacting oropouche virus expansion.

“Changes to temperature and precipitation can affect transmission, for example, rising temperatures can enhance the rate of development of culicoides midges, one of the virus’ main transmission vectors in South America alongside mosquitos.”

Although oropouche virus is not new, the factors driving the recent sharp increase highlight the need for further investigation, she explained.

“Until advancements are made in vaccine development or mosquito and midge control, or until natural immunity within the population in Brazil [and other affected countries] increases, the challenge posed by this neglected tropical disease will persist.”

Will I catch it?

Dr Philip Veal, travel health consultant at the UK Health Security Agency (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.”

The UKHSA also added that all cases diagnosed in Europe were acquired elsewhere.

Who is most at risk?

“There is much we still do not know about the oropouche virus but one of the main concerns arising from the current outbreak in South America is its potential harmful effects on unborn foetuses,” said Paixao.

In July, the PAHO issued an alert regarding the potential transmission of the oropouche virus from mother to child in Brazil.

“Some very limited studies have suggested that antibodies against the virus have been found in children born with microencephaly and that there may be a link between infection, miscarriage, and foetal deaths in Brazil, but further research is needed to investigate a potential causal link,” says Paixao.

What are the symptoms?

The London School of Hygiene and Tropical Medicine clarified that common symptoms include a rash, headache, muscle or joint pain with weakness. Affected individuals will typically experience a fever illness three to eight days after infection

In addition, in some cases individuals may also experience gastrointestinal symptoms and sensitivity to light. The research centre also added that severe cases are rare but can lead to neurological symptoms similar to meningitis.

Can it be treated?

“As of now, there are no specific antiviral treatments or vaccines available for oropouche virus,” said Goncalves. “Treatment primarily focuses on managing symptoms and providing supportive care.”

Patients are typically advised to rest, stay hydrated, and take over-the-counter pain relievers such as paracetamol to reduce fever and alleviate pain.

“In more severe cases, hospitalisation may be necessary to provide supportive care, especially if complications arise, although severe cases are relatively rare,” added Goncalves.

What should I do if I am planning to travel to an affected area?

“When travelling to affected areas, you can avoid the infection by preventing insect bites. Use insect repellent, cover exposed skin and sleep under a treated bed net,” said Veal. “Plan ahead and visit the TravelHealthPro website to look up your destination and the latest health information and advice, particularly if you are pregnant.”