Oropouche resources

Oropouche virus is endemic to the Amazon basin and was first detected in 1955 near the Oropouche River in Trinidad and Tobago. Prior to 2000, Oropouche outbreaks were reported in Brazil, Panama and Peru. Since then, more countries have reported cases. In 2023, Oropouche virus caused large outbreaks in both endemic areas and new areas in South America and the Carribean, with Cuba confirming its first case in June 2024. 

• Aug. 16, 2024–The CDC issued a HAN on Increased Oropouche Virus Activity and Associated Risk to Travelers

Oropouche virus is spread to humans by biting midges and possibly some mosquitoes (including Culex mosquitoes). Sexual transmission is possible, as replication-competent virus has been found in semen, but no sexually-transmitted cases have been identified. While there have been travel-associated cases in the U.S., local transmission has not been seen.

Vertical transmission is possible with a few cases reported. It is unclear how common verticle transmission is. Fetal loss and congenital abnormalities have occurred. Cases of microcephaly, as seen with Zika vertical transmission, were reported in Brazil.

Most people who are infected with Oropouche virus will develop symptoms. The incubation period is 3-10 days, after which fevers, headaches (often severe), chills, myalgias and arthralgias start. Other symptoms include photophobia, retroorbital or eye pain, nausea and vomiting and a maculopapular rash that starts on the trunk and travels out to the extremities. Less common symptoms are abdominal pain, diarrhea and hemorrhagic symptoms (eg, epistaxis, melena, petchiae). Symptoms last 2-7 days, but in up to 60% of people, their symptoms will return a few days or weeks later. Patients typically recover but deaths have been reported.

Approximately 4% of patients develop neuroinvasive symptoms (eg, meningitis, encephalitis), with cerebrospinal fluid (CSF) revealing pleocytosis and protein elevation. 

In case reports from Brazil and Cuba, findings among women with Oropouche virus infection during pregnancy have included stillbirth and congenital anomalies of the central nervous system.

Diagnosis is made based on symptoms and travel and exposure history. Serum IgM is typically positive after a week of illness, with IgG antibodies rising after. 

Patients with neuroinvasive disease should have CSF examined for cell count and protein along with viral DNA, although it is often absent. Viral DNA is typically present in the serum for the first several days of infection, and samples can be sent from local or state health departments to CDC for RT-PCR testing in serum or CSF.

Prevention of midge and mosquito bites is the only known way to prevent Oropouche infection. Using Environmental Protection Agency (EPA)-registered insect repellents labeled for flies, biting flies or Culicoides (biting midges and no-see-ums). Take precautions when traveling to prevent bites.

Vaccinations

There are no vaccines available for Oropouche. 

Treatment 

There is no antiviral treatment available for Oropouche. As with dengue, avoidance of aspirin-containing drugs and other nonsteroidal anti-inflammatory drugs is recommended to reduce the risk of bleeding.

Prevention infection & control

In acute health care facilities, standard precautions are recommended for all patient care and laboratory professionals. Because of the possibility of sexual transmission, safe sex practices with those returning from an endemic area is recommended. 

When you return from traveling to an area with Oropouche virus, prevent bites from midges and mosquitoes for 3 weeks after turning to prevent local transmission.

As of March 7, 2025, non-congenital and congenital Oropouche virus disease are nationally notifiable conditions. Cases should be reported to state or local health departments and to ArboNET for surveillance.