Oropouche virus disease

Oropouche virus belongs to the Orthobunyavirus group and was first identified in Trinidad in 1955. It circulates in a forest cycle involving non-human primates and sloths, and in an urban cycle between midges and people. WHO describes this dual pattern, and TravelHealthPro notes that the vector midges are found in the Americas and Caribbean but not in the UK, so there is no local transmission here.

Outbreaks in 2024 occurred across multiple countries including Brazil, Colombia, Peru, Ecuador and several Caribbean nations, extending to areas with no previously documented local transmission, according to TravelHealthPro.

TravelHealthPro describes symptoms beginning 4 to 8 days after infection, with fever, headache, joint and muscle pain, and sometimes nausea, rash and eye discomfort. WHO adds chills and vomiting. The illness resembles dengue and chikungunya, which is why misdiagnosis is common in places where those infections also circulate.

The first episode typically settles within a week, though some people take weeks to recover fully. TravelHealthPro states that symptoms may return a few days or even weeks later in approximately 60 per cent of cases, so a relapse does not mean a new infection or a treatment failure.

• Fever, chills and severe headache.

• Joint, muscle and back pain.

• Nausea, vomiting, rash and light sensitivity.

• Return of symptoms after a symptom-free interval in some people.

Most people recover without lasting problems, but both TravelHealthPro and WHO describe rare serious complications, including meningitis and encephalitis, and TravelHealthPro lists Guillain-Barre syndrome. Fatal cases in previously healthy young adults were documented for the first time in 2024.

WHO reports that in Brazil in 2024 there were reports of possible fetal infection transmitted from mothers infected during pregnancy, including cases of stillbirth, miscarriage and newborns with microcephaly, and notes that investigations into causation continue. TravelHealthPro confirms mother-to-baby transmission and advises pregnant travellers to consult healthcare providers before travelling to affected regions.

WHO states that diagnosis is made by RT-PCR, and no commercial rapid tests exist. In the UK, testing of a returning traveller with fever is arranged through specialist laboratories and malaria is excluded first. There is no specific treatment: care is rest, fluids and pain and fever relief, with hospital care for complications. People with a possible dengue illness are usually advised to avoid anti-inflammatory painkillers until dengue is excluded.

There is no vaccine. TravelHealthPro advises avoiding insect bites with fine-mesh bed nets and screened accommodation, and WHO lists protective clothing and repellents containing DEET, IR3535 or icaridin. The midges are active from dawn to dusk, and some mosquitoes bite at other times, so protection is needed throughout the day and evening. Because sexual transmission is possible, TravelHealthPro suggests condom use during and for six weeks after travel.

Contact NHS 111 or a GP urgently for fever within a few weeks of returning from the Americas or Caribbean, and call 999 for confusion, severe headache with neck stiffness, weakness, seizures or breathing difficulty. Pregnant women who have travelled to an affected region should speak to their midwife or obstetric team whether or not they were unwell.