By Ethan Covey
Cases of Oropouche virus, an emerging arthropod-borne virus, have been identified in U.S. citizens upon returning from travel to Cuba.
Upon publication of a CDC report on Aug. 27, 2024, 21 cases of Oropouche virus disease had been confirmed (MMWR Morb Mortal Wkly Rep 2024;73[35]:769-773). Current data from ArboNET, which is updated weekly, lists a total of 74 cases as of Sept. 17. Cases have been confirmed in five states, with the majority in Florida.
“The report provided a clinical description of the cases, which assisted in refining the suspect case definition and helped clinicians and public health jurisdictions recognize potential cases for testing,” said Carolyn Gould, MD, the medical officer with the CDC’s Division of Vector-Borne Diseases.
Most of the patients had fever and other symptoms such as headache, muscle aches, fatigue, joint pain, nausea, vomiting, diarrhea and rash that went away without specific treatment. At least three people saw rebound symptoms after the original infection ended, which is a common characteristic of Oropouche virus disease. Three people were hospitalized, and no deaths have been reported.
However, two deaths have been reported among people with Oropouche virus disease in Brazil. And vertical transmission associated with adverse pregnancy outcomes has increased concern regarding risks posed by the virus.
While case counts in the United States have been increasing, the CDC has stressed that all cases have been linked to the outbreak in Cuba, and there is no evidence that the virus is spreading independently in the United States.
“The number of Oropouche disease cases reported did increase this year,” Dr. Gould said. “The outbreak in new locations like Cuba is likely influencing what is happening in terms of the number of travel-associated cases.”
Dr. Gould also noted that increased surveillance may be contributing to the higher case counts.
“As awareness of Oropouche virus has increased among clinicians and public health professionals, surveillance and testing of returning travelers with symptoms of possible Oropouche virus disease have been increasing,” she said. “New assays to detect Oropouche are being developed and will increase capacity for testing in more jurisdictions. Surveillance and testing have also been increasing in other countries.”
Over time, Dr. Gould said multiple factors will likely affect incidence of Oropouche virus disease, including weather patterns, vector control activities and use of personal protective measures to prevent bug bites.
Many questions remain regarding Oropuche virus disease, and the CDC is working with partners to better understand the duration and course of disease over time, duration of viremia after infection, risk factors for the rare occurrence of severe disease, risk for potential adverse outcomes for infections occurring during pregnancy, and primary vector(s) driving the outbreaks in other countries and risk for potential local transmission in the United States and its territories.
Dr. Gould reported no relevant financial disclosures.
