On December 20, 2023, the International Health Regulations National Focal Point (IHR NFP) in Argentina alerted the Pan American Health Organization/World Health Organization (PAHO/WHO) of a human case of Western Equine Encephalitis Virus (WEEV) infection.
Key points
- This is the first confirmed human case reported after more than two decades, since the last reported human cases in Argentina occurred in 1982/1983 and 1996.
- WEE is a rare mosquito-borne viral disease that affects equines and humans. Most human cases are associated with epidemics in birds or horses.
- The disease caused by a virus of the same name, which belongs to the genus Alphavirus of the Togaviridae family, to which the EEE and VEE viruses also belong.
- The virus has the potential to spread to other areas through the migration of infected birds or the movement of people and animals carrying the virus.
- Given that birds act as a reservoir, they can act as amplifying hosts for viral dissemination to other countries.
- At-risk groups include people who live, work, or participate in outdoor activities in endemic areas or where there are declared active disease outbreaks in animals.
- In humans, the WEE virus can cause disease ranging from subclinical or moderate symptoms to severe forms of aseptic meningitis and encephalitis.
