Oropouche virus (OROV) causes Oropouche fever (OROF); the first case was identified in a forest worker in Trinidad and Tobago in 1955. Since then, it has caused at least half a million infections in South America, although that number is likely a low estimate, according to a 2022 study in npj vaccines. That study highlighted the lack of vaccines; while several vaccine candidates have been evaluated in recent years, they were found to be ineffective against OROV. The report also emphasized the need for rapid diagnostic tests for this virus; diagnosis is usually based on an evaluation of symptoms.
The disease is spread by infected biting midges, as well as some mosquitoes. There is a three-to-ten day incubation period before a fever sets in, along with headache, chills, and joint or muscle pain. There are some other symptoms that may arise as well including cramps, diarrhea, nausea, and a rash. The illness might last for about a week, with people usually recovering on their own. But sometimes these symptoms will recur days or weeks later.
Symptoms of the disease can be similar to other vector-borne diseases like dengue, malaria, or Zika.
In a small number of Oropouche fever patients, about 4 percent, neuroinvasive disorders can arise, and people may experience a variety of additional symptoms including dizziness, pain, and fatigue.
There had been "very few" deaths attributed to the virus, without any directly confirmed to have been caused by the virus itself.
However, Brazil's health ministry has now attributed the deaths of two women under the age of 30 in Bahia state to OROV, according to the Pan American Health Organization (PAHO).
Although the virus was thought to only pose a problem in South America, Cuba reported its first outbreak of OROF in May 2024. There were 74 confirmed cases at the time, and the World Health Organization noted that the local population was very likely to see additional cases. Since Cuba is an international tourist destination, WHO also noted that the disease may also spread to new areas (in addition to the countries where the disease is already spreading).
In 2017, Professor Luiz Tadeu Moraes Figueiredo of the University of São Paulo's Ribeirão Preto Medical School (FMRP-USP) noted that, "Oropouche is a virus that could potentially emerge at any moment and cause a serious public health problem in Brazil."
A July 2024 report in The Lancet Infectious Diseases called OROV a neglected virus, and noted that knowledge gaps surrounding the virus should be promptly addressed. The study added that the virus has been detected in many vertebrates, and it's now time to determine whether the disease is spreading in other ways.
Sources: Centers for Disease Control and Prevention (CDC), npj vaccines, PAHO, The Lancet Infectious Diseases
