Oropouche Fever

Oropouche fever is an arboviral illness caused by Oropouche virus (Orthobunyavirus), transmitted mainly by the biting midge Culicoides paraensis, and also by Culex mosquitoes.

• Endemic in the Amazon basin (Brazil, Peru, Colombia, Ecuador), Panama, and the Caribbean (Trinidad, Cuba), with large expansion in 2024 to 2025 including outbreaks in Cuba, Brazil, and travel cases in Europe and the United States.
• Sloth and primates are sylvatic hosts; urban cycle between humans and midges.
• Vertical transmission has been documented, linked to miscarriage, stillbirth, and congenital malformation (microcephaly).

• Abrupt fever, severe headache, retro orbital pain, myalgia, arthralgia, photophobia, nausea, and rash.
• Relapse of symptoms after a few days of recovery in about 60%.
• Neuroinvasive disease (aseptic meningitis, encephalitis) in a minority, and rarely bleeding (epistaxis, gum bleeding).
• Deaths reported in 2024 in previously healthy patients; pregnancy complications are a concern.

• RT-PCR on serum or CSF in the first days; IgM ELISA; plaque reduction neutralisation (cross reactions with other orthobunyaviruses).
• Blood: leucopenia and mild thrombocytopenia; liver enzymes may be raised.
• Exclude dengue, Zika, chikungunya, malaria, leptospirosis, and yellow fever (clinically similar).
• Pregnant women need fetal ultrasound and neonatal evaluation.

• Supportive therapy: rest, fluids, paracetamol for fever and pain (avoid aspirin and NSAIDs if haemorrhage possible).
• Monitor for neurological signs, bleeding, and dehydration; hospitalisation for severe disease.
• No specific antiviral or licensed vaccine.
• Pregnant women: close obstetric follow up with serial ultrasound; neonatal evaluation of exposed infants.
• Vector control (reduce midge breeding sites such as banana and cacao residue), insect repellents (DEET, picaridin), protective clothing, and screens.
• Public health notification and surveillance.