Oropouche Virus: What You Need to Know

Oropouche virus (OROV) is an emerging disease that is primarily spread by the bite of infected midges, as well as some species of mosquitoes. There have been several outbreaks of the virus throughout South America, Central America, and the Caribbean, and travel-associated cases have been reported in the United States, primarily in Florida, along with cases in Kentucky and New York.

OROV is transmitted to humans primarily by the bite of female Culicoides paraensis midge (order Diptera, family Ceratopogonidae). Also known as no-see-ums, these tiny flies are persistent biters when active at dawn and dusk and throughout the day in low wind conditions. The primary characteristic used to identify Culicoides species are unique vein patterns on the wings. Management options for these pests are limited as the eggs and larval habitats are located in water-holding plants, tree holes, decaying vegetation, and other moist substrates throughout the landscape. Barrier treatments to vegetation offer limited and temporary solutions as adult Culicoides are known to rest high in tree canopies and away from the limits of most barrier applications. Some species of mosquitoes, including Cx. quinquefasciatus, Cq. venezuelensis, and Ae. serratus have been found to be naturally infected with OROV. They are thought to be secondary vectors though their role in transmission is not well known.

As with mosquitoes, the best defense against Culicoides is prevention against biting. Staying indoors during peak biting times is not always possible so repellents are a good option to reduce biting activity. Most store bought repellent brands containing DEET and Picaridin are labeled for biting midges and mosquitoes and will provide effective control for extended periods. Some essential oil based formulations, such as oil of lemon eucalyptus, have shown short term repellency but are not as effective as the more established repellent products. The most important factor is to take steps in avoiding biting insects to minimize the chances of contracting an insect-borne disease.

Symptoms of Oropouche virus include fever, headache, myalgia, joint pain, photosensitivity, and nausea. It is sometimes misdiagnosed as Dengue or Zika virus infection. Symptoms typically last less than a week (2–7 days) and can often reoccur a few days or even weeks later. Most people with Oropouche recover within several days to one month.

Per the CDC, in the last 25 years, cases of Oropouche have been identified in many countries, including Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Panama, and Peru. In addition, one child was found to be infected in Haiti in 2014. And in June 2024, Cuba reported its first confirmed Oropouche case.