Insect-borne oropouche virus is spreading rapidly: What you need to know

No case in India yet but expert advises precautions similar to dengue and malaria.

The treatment is symptomatic and is similar to what is given in other arboviral (insect-borne) infections. (File/ Representational Photo)

An insect-borne virus, much like the mosquito-borne dengue virus, called oropouche, has been wreaking havoc in South America with more than 8,000 cases reported since August 1. Now the virus has jumped geographies through travellers and it has also been reported in the US and Europe, which never had a history of this virus.

What is this virus all about and how does it spread?

According to Dr Rommel Tickoo, Director, Internal Medicine, Max Superspeciality Hospital, Delhi, oropouche, also called sloth fever, is similar to dengue and is spread primarily by the bite of infected biting midges, a kind of fly. “Some mosquitoes can also spread the virus. Now local transmission by other vectors are under investigation. Currently it is limited to South America and Caribbeans and so far, cases have not been reported in India. It was detected for the first time in 1955 and was found in Trinidad and Tobago. Since then, the virus has had limited circulation in parts of South America,” he says.

What are signs and symptoms?

Most cases of oropouche fever are mild with symptoms similar to dengue, including headache, fever, muscle pain, nausea, eye pain and rash but in some cases the virus can also cause meningitis and encephalitis. “It’s difficult to identify without a molecular lab diagnosis. It’s a self-limiting illness and is rarely fatal. However, it could be a challenge for pregnant women where complications can arise like foetal deaths, stillbirth, birth defects and an underdeveloped brain in the new-born, the last being characteristic of Zika,” says Dr Tickoo.

The symptoms typically last less than a week (2–7 days) and can recur a few days or even weeks later. Most people with oropouche recover within several days to one month.

What’s the treatment?

The treatment is symptomatic and is similar to what is given in other arboviral (insect-borne) infections. There’s no vaccine. However, the US Centers for Disease Control and Prevention (CDC) recommends using acetaminophen (paracetamol) to treat fever and pain instead of aspirin or similar nonsteroidal anti-inflammatory drugs to reduce the risk of haemorrhaging.

Why have the cases increased and should India remain cautious?

According to a Lancet editorial, the increased dissemination, as with other vector-borne diseases, is driven by factors like climate change, human and animal mobility and behaviour, deforestation, and land use. Another factor is that the oropouche virus genome (complete set of genetic material in any organism) is formed by three RNA (ribonucleic acid involved in protein synthesis) segments, while most insect-borne viruses consist of one. Mutations may result from swapping of segments. These genetic changes can impact the virus’ ability to infect, cause disease, spread, evade the immune system, and develop drug resistance. After reporting of imported cases in Europe, it is expected that oropouche fever could be reported in travellers in other regions.

Dr Tickoo says it’s important to take precautions similar to what we do for dengue and malaria. “The best way to protect yourself and your family from oropouche is to prevent bites from midges and mosquitoes,” he adds.