Oropouche: Fiocruz and PAHO prepare manual for entomologists in the Americas

Since the end of 2023, several outbreaks of Oropouche fever have occurred in the Region of the Americas. In Brazil alone, there were more than 17,400 cases between 2023 and 2025, according to data from the Ministry of Health.

Fulfilling its mission to provide answers to public health, professionals from the Oswaldo Cruz Institute (IOC/Fiocruz) have been contributing to a series of initiatives. The latest is the production of an operational manual to guide teams of entomologists in the Americas in identifying the main taxonomic and ecological characteristics of the insect species that vectors the disease.

The document prioritized species of greater interest to public health and whose identification uses techniques and equipment easily found in laboratories. Called Operational Document for the Identification of Culicoides Latreille (Diptera: Ceratopogonidae), the guide was prepared by Maria Luiza Felippe Bauer and Maria Clara Alves Santarém, curators of the Ceratopogonidae Collection at IOC/Fiocruz, linked to the Diptera Laboratory. The product was produced in partnership with the Pan American Health Organization (PAHO).

The document highlights the diagnostic characteristics of the main species found frequently and in abundance in entomological surveys in Central and South America, as well as their distribution and bionomics. An illustrated key for identifying the species of the paraensis group is also provided.

Caused by the Orthobunyavirus oropoucheense virus, the Oropouche fever is transmitted mainly by the Culicoides paraensis, popularly known in Brazil as maruim (no-see-um) or mosquito-pólvora (gunpowder midge). In addition to Brazil, cases of the disease are spread across Bolivia, Colombia, Cuba, Guyana, Peru and the Dominican Republic.

Maruins are very small insects, which makes them very difficult to catch and identify, as they measure from 1.5 mm to 3 mm. Its bite is known to be very painful. Find out more about the insect and check out the news special on Oropouche.

Watch below the recent session of the IOC/Fiocruz's Study Center on Contributions of the clinic, entomology and virology to the national emergency of the Oropouche virus.