What is Mpox? How Does It Spread and Can It Be Treated?

The global eradication of smallpox more than 40 years ago was one of the greatest achievements in public health history, vanquishing a cause of death, blindness and disfigurement that had plagued humanity for at least 3,000 years. However, its success led to the end of a global vaccination program that provided protection against related diseases. Those include mpox, which has spilled over from its animal hosts to infect humans in West and Central Africa with increasing frequency since the 1970s. Now a mutated strain of the mpox-causing monkeypox virus has been detected in several African nations, the US, UK, Thailand, and India, among other countries. The World Health Organization and Africa Centres for Disease Control and Prevention each declared a health emergency in August 2024.

Mpox is a less contagious cousin of smallpox with generally milder symptoms, although it still can be lethal. While about 30% of smallpox patients died, the fatality rate for mpox ranges from less than 0.1% to as high as 6%. The disease was discovered at the Statens Serum Institut in Copenhagen in 1958, where it was spreading in monkeys kept for research. That led to its former designation: monkeypox. Although the main animal source of the monkeypox virus hasn’t been identified, rodents are suspected of playing a part in transmission. The WHO changed the name of the disease to mpox in 2022 to curb what it called racist and stigmatizing language surrounding the infection.