Oropouche virus Emergence unit

It includes:

• A timeline of the disease’s epidemiology.
• A review of key scientific articles published in journals over the last month.
• A review of articles published in the press over the last month.
• A “factsheet” with general information about the disease.
• Guidelines from health agencies.

Oropouche virus disease: an arbovirosis

Oropouche virus disease was first detected in 1955 in Trinidad and Tobago, near the Oropouche River. It is an arboviral disease caused by the Oropouche virus (OROV), which belongs to the genus Orthobunyavirus in the family Peribunyaviridae. The virus is primarily transmitted to humans through the bite of small midges, mainly Culicoides paraensis. It is a widely underdiagnosed disease, often mistaken for other arboviruses such as Dengue, Chikungunya, or Zika. There is currently no specific treatment or vaccine for the Oropouche virus.

Since 2023, rapid expansion of the Oropouche virus

Oropouche virus disease is endemic in several regions of Central and South America, as well as the Caribbean, where it circulates. Starting in 2023, the virus caused major epidemics in historically endemic regions, but also in regions free of Oropouche. As of September 10, 2024, the Americas have reported 9,852 confirmed cases and 2 deaths across six countries: Bolivia, Brazil (7,931 cases and 2 deaths), Colombia, Cuba, Peru, and recently, the Dominican Republic. Cuba reported its first Oropouche outbreak in June 2024, with 500 confirmed cases and over 10,000 suspected cases, according to PAHO as of September 23. Many imported cases have been reported in the USA (21 cases) and Europe (23 cases), mainly in travelers returning from Cuba.

The current situation shows a rapid spread of the Oropouche virus, including in areas previously free of cases, while the severity of the infection appears to be increasing, potentially linked to vertical transmission with complications for pregnant women and their fetuses.

The threat posed by the Oropouche virus should not be underestimated. Significant gaps exist in understanding its epidemiology, ecology, pathogenesis, and the risk of reassortment with other Orthobunyaviruses. Addressing these research gaps and developing effective countermeasures are crucial to improving risk assessments and creating effective public health strategies against this neglected disease.