Once confined to the Amazon region, the mysterious insect-borne virus that causes Oropouche fever has been expanding its range since late 2023, raising international concern. There have been more than 8,000 confirmed human infections in the Americas so far this year, most of them in Brazil, but Peru, Bolivia, Colombia and Cuba have also been affected.
In July, authorities in Brazil reported the deaths of two adults from the disease — the first fatalities recorded since the virus was identified almost 70 years ago. Brazilian officials are also investigating cases of fetal deaths and malformations that might have been caused by the virus, which investigations have shown can spread from a pregnant person to the fetus1. There are no vaccines or treatments for the disease.
Earlier this month, the Pan American Health Organization upgraded its risk level for Oropouche from moderate to high, citing the virus’s geographical spread and the occurrence of fatal cases, which are notable for a disease that has historically been known to cause mild to moderate symptoms. On 23 August, the World Health Organization published a note stating that the public-health risk posed by the virus is high at the regional level and low at the global level. The US Centers for Disease Control and Prevention has advised close surveillance of people returning from affected areas. Cases of Oropouche infection have been identified in people who have travelled to the United States, Spain, Italy and Germany from Brazil and Cuba.
