US officials are concerned about the deadly mosquito-borne Oropouche virus that threatens the country as thousands of cases are reported across South America.
As of August 1, more than 8,000 cases of Oropouche virus have been reported, mostly in South America. Europe has also reported dozens of cases of travelers carrying the disease, which has U.S. health officials worried and looking for ways to prevent the disease from spreading in the country.
The Pan American Health Organization, a regional arm of the World Health Organization (WHO), has issued an epidemiological alert for the Oropouche virus. The agency has also raised the public health risk level for the Americas region to high.
“The disease has been historically described as mild. However, the geographic spread and emergence of severe cases underscore the need for increased surveillance and the potential for severe disease,” the agency said.
The U.S. Centers for Disease Control and Prevention (CDC) also issued a health advisory, warning service providers and public health agencies to be on the lookout for new cases. The agency recommends that pregnant women avoid traveling to areas affected by the outbreak. According to the CDC, at least 21 U.S. travelers returning from Cuba have tested positive for the Oropouche virus.
Oropouche is named after a village in Trinidad and Tobago where the virus emerged in 1995. Since then, about 500,000 cases have been recorded. However, scientists’ knowledge of the disease is limited. Leading medical journal Lancet even called it a “mysterious menace” in a recent report.
According to the CDC, about 60 percent of people infected develop symptoms. Symptoms are similar to those of dengue fever or Ebola, including sudden fever, chills, headache, muscle pain, and stiffness. Other symptoms may include eye pain, fatigue, and a rash. In rare cases, the disease can infect the nervous system, causing meningitis. Oropouche virus is from a different family than Zika, but it is similar in its risks and mystery.
Mosquitoes are the intermediate hosts that transmit fever caused by the Oropouche virus. Photo: Pexel
The virus is transmitted to humans through insect bites, especially by Aedes mosquitoes. It is endemic to the Amazon basin in South America, especially in dense forests. The transmission cycle continues between the insect and other hosts such as rodents, sloths, and birds. The disease is sometimes called “sloth fever.” People who visit or explore these areas may be bitten by infected insects, carrying the virus back to urban areas.
According to the Pan American Health Organization, climate change and deforestation are creating more opportunities for humans to come into contact with infected insects, increasing the risk of transmission. The current outbreak is spreading rapidly in countries where the virus has never been circulating, such as Bolivia, Brazil, Colombia, Cuba and Peru.
The risk of sustained local transmission in the Americas is low, said Dr. Erin Staples, an epidemiologist in the CDC’s Division of Communicable Diseases. However, the risk is higher in Puerto Rico and the Virgin Islands, which have similar ecosystems to Cuba.
Experts say the geographic shifts suggest the virus may find its way to new intermediate hosts. 2024 was also the first year of reported deaths from Oropouche virus and evidence that the disease can be transmitted from pregnant women to their fetuses, posing risks to the birthing process.
Earlier this year, Brazil recorded two deaths of young, healthy women. The third death was a middle-aged man.
“We are seeing more and more cases of rare and unusual disease that are clinically symptomatic or fatal,” said Dr. Staples.
There is currently no vaccine for the Oropouche virus, nor is there any specific treatment. Patients usually need to be tested for diagnosis, but these kits are not available in private clinics. They need to undergo tests first to rule out more common pathogens such as dengue fever.
Dr Janet Hamilton, executive director of the Epidemiology Council, said people should take proactive measures to prevent mosquito bites, avoid going out at dawn and dusk, dress appropriately to protect the skin from mosquitoes and insects, and use effective mosquito repellent.