The Oropouche virus, which causes a disease nicknamed “sloth fever” for one of the animals that can be infected, has seen its first cases in the U.S.
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.
Fetal deaths and deformities may have been caused by the virus, which can pass from pregnant women to their fetuses. Brazilian officials are investigating. The illness has no vaccinations or therapies.
The Pan American Health Organization raised its risk rating for Oropouche from moderate to high earlier this month, citing the virus's geographical expansion and fatal instances for a condition with mild to moderate symptoms.
The World Health Organization reported on August 23 that the virus poses a high regional public-health risk but a low worldwide danger. The US CDC advises strict observation of persons returning from impacted areas.