Oropouche Virus: An Emerging Neuroinvasive Arbovirus.

Oropouche virus (OROV) is an arthropod-borne virus (arbovirus) in the Orthobunyavirus genus and Peribunyaviridae viral family that is endemic to parts of South America, Central America, and the Caribbean. It has recently emerged in Cuba, and travel-imported cases are recently being reported in the United States and Europe. Typically maintained in a sylvatic cycle between certain forest sloths, non-human primates, birds, and mosquitoes, OROV disease outbreaks can occur in an urban cycle between certain biting midges and/or mosquitoes and humans. Clinically, approximately 60% of infections are symptomatic with an abrupt fever and non-specific influenza-like illness within 3 to 10 days. Many initial OROV infections can present similarly to chikungunya, dengue, and Zika virus infections. Interestingly, OROV infections can follow a biphasic course with recurrence of symptoms approximately 1 week after initial symptom onset. Concerningly, similar to Zika virus, it appears that vertical transmission of OROV may occur with potentially adverse effects on fetal development including miscarriages. Neuroinvasion of OROV occurs in animal models, and human cases of meningitis, encephalitis, and peri-infectious Guillain-Barré syndrome have all been reported. Diagnosis is either through detection of OROV nucleic acid, OROV immunoglobulin M, or OROV neutralizing antibodies in the serum and/or cerebrospinal fluid. No antiviral treatments are available, and there are no current vaccines. Preventing mosquito and biting midge bites is key. Neurologists should be aware of and report any potential neuroinvasive OROV disease cases to local/state/territorial health departments. ANN NEUROL 2024.