Researchers screening blood donors during Argentina's western equine encephalitis outbreak found one donor carrying the virus in their bloodstream with no symptoms, a finding published in the CDC journal Emerging Infectious Diseases.
Western equine encephalitis virus reemerged in Argentina and Uruguay in late 2023 after nearly three decades without a confirmed human case in Argentina. Across the two countries from November 2023 through April 2024, the regional outbreak produced 217 human cases, 12 of them fatal, along with 2,548 equine cases. Argentina's own confirmed human count for the outbreak has been reported as 107 cases with 12 deaths, a lower figure that reflects the narrower national scope rather than a contradiction.
