Oropouche virus disease (OROV) is a febrile infection caused by an arbovirus of the genus Orthobunyavirus, belonging to the family Peribunyaviridae. First identified in 1955 in Trinidad and Tobago, OROV has caused cases and outbreaks in several South American countries. Outbreaks have been most frequent in the Amazon Basin region, where the most known vector, the midge (Culicoides paraensis), maintains a sylvatic cycle involving hosts such as sloths and non-human primates.
Oropouche (OROV) is an arbovirus and member of the Peribunyaviridae family. It was first detected in 1955 near the Oropouche River in Trinidad, followed by several outbreaks in Brazil towards the end of the last century. In 2024, OROV cases were reported in the Region of the Americas. As of 23 July 2024, over 7,700 cases have been reported in five countries in the region: Brazil (6,976 cases as of mid-2024), Bolivia, Peru, Cuba, and Colombia.
As with any emerging event, the number of reported cases may vary as the situation evolves. For the most up-to-date information, access the latest PAHO Epidemiological Alert and Update.
Oropouche is a vector-borne disease transmitted among people primarily through bites of an insect commonly known as a midge (Culicoides paraensis). The mosquito Culex quinquefasciatus can also be involved in transmission.
Symptoms include sudden onset of fever, headache, stiff joints, aches and pains and, in some cases photophobia, diplopia (double vision), nausea and persistent vomiting. Symptoms can last from five to seven days.
Rarely, severe cases can include aseptic meningitis. Full recovery can take several weeks.
On 25 July 2024, Brazilian authorities reported two deaths attributed to Oropouche. Previously, scientific literature had not reported deaths attributable to OROV.
In July 2024, Brazilian authorities reported the investigation of cases of OROV transmission from expectant mother to child. Please see PAHO Epidemiological Alerts and Updates for more details.
To date, Brazil is the only country to report possible cases of maternal to fetus transmission of Oropouche during pregnancy. The only previous similar observation reported in the scientific literature was during an outbreak of Oropouche in Manaus, Brazil, between 1980 and 1981, where OROV infection was observed in nine pregnant women, two of which miscarried.
Oropouche is confirmed by laboratory test No rapid test currently exists.
If you think you have symptoms of Oropouche, contact your health care worker for advice, testing and medical care. Evaluation by a health care professional is key to the proper management of symptoms and disease evolution. As Oropouche has similar clinical manifestations in infected persons as dengue and other arboviruses, it is important that health care professionals consider differential diagnoses and treat patients accordingly.
There are currently no specific treatment or vaccine for Oropouche. In addition to rest and fluids, treatment for symptoms can include painkillers and fever-reducing medications.
Recommended measures to prevent transmission through midge and mosquito bites include protecting homes with fine mesh mosquito nets on doors and windows, as well as beds and furniture where people rest; wearing clothing that covers legs and arms; applying repellents containing DEET, IR3535 or icaridin. As midges are much smaller than mosquitoes, traditional mosquito nets will not protect against their bites.
While current outbreaks remain under investigation, PAHO has advised effected countries to strengthen surveillance and implement vector control measures to and risk communication help prevent a further increase in cases.
Four genotypes of Oropouche have been identified. Infection with any genotype should generate antibodies to protect against future reinfection.
Everyone living in areas with arbovirus transmission, including Oropouche, should take precautions to prevent mosquito and midge bites. This includes those with pre-existing conditions, the elderly, young children and pregnant women.
PAHO calls on countries to implement vector prevention and control actions, including strengthening entomological surveillance, reducing mosquito populations (and other transmitting insects), and educating the population about personal protection measures.
PAHO has also issued guidelines to assist countries in the detection and surveillance of the Oropouche virus for possible cases of vertical infection, congenital malformation and death.
PAHO continues to provide ongoing technical support to affected countries to strengthen their capacity to detect and characterize the Oropouche virus. This includes the distribution of reagents for simultaneous molecular detection and a protocol that is currently available in 23 countries to facilitate early detection of the virus.
PAHO has also organized international workshops on the molecular surveillance of emerging and re-emerging arboviruses, including on OROV.
This Q&A is based on available knowledge and information as of 23 July 2024. For the most recent PAHO data, please see PAHO Epidemiological Alerts and Updates.