[4] Since its discovery in 1955, there have been more than 30 epidemics of OROV in countries including Brazil, Peru, and Panama, with over half a million diagnosed cases in total.

Fever, headache, and muscle and joint pains are most common; a skin rash, unusual sensitivity to light, and nausea and vomiting may also occur.

In severe illness, however, the central nervous system may be affected, with symptoms of meningitis and encephalitis, and a tendency to excessive bleeding has been reported in up to 15% of cases.

[8][6] In serious cases, particularly in large outbreaks, the central nervous system may be affected with symptoms of meningitis and encephalitis, including severe headache, dizziness, neck stiffness, double vision, darting of the eyes, uncoordinated movements, and evidence of viral infection in the cerebrospinal fluid (CSF).

[13] This virus is an arbovirus and is transmitted among sloths, marsupials, primates, and birds through mosquito species including Aedes serratus and Culex quinquefasciatus.

[1] The oropouche virus has evolved to an urban cycle infecting humans though a midge, Culicoides paraensis, as its main transporting vector,[1] with mosquitoes such as Culex quinquefasciatus also possibly contributing.

[3] In Brazil, OROV was first described in 1960 when it was isolated from a three-toed sloth (Bradypus tridactylus) and Ochlerotatus serratus mosquitoes captured nearby during the construction of the Belém–Brasília Highway.

[3] Large epidemics are common and very swift, one of the earliest and largest having occurred at the city of Belém, in the Brazilian Amazon state of Pará, with 11,000 recorded cases.

In some cases this virus has also been recovered from the cerebrospinal fluid, but the route of invasion to the central nervous system (CNS) remains unclear.

[9] As the infection progresses, the virus crosses the blood-brain barrier and spreads to the brain parenchyma leading to severe manifestations of encephalitis.

[9]The oropouche virus spreads through the neural routes during early stages of the infection, reaching the spinal cord and traveling upward to the brain through brainstem with little inflammation.

[6][7] There is no cure or specific therapy for Oropouche fever; only symptomatic treatment (such as analgesics for pain relief and fluids to prevent and treat dehydration) is recommended.

[19][20] Aspirin is not a recommended choice of drug because it can reduce blood clotting and may aggravate the hemorrhagic effects and prolong recovery time.