Overview
What is mpox?
Mpox (previously named monkeypox) is caused by infection with mpox virus, a member of the genus Orthopoxvirus in the family Poxviridae. There are currently more than 80 poxviruses known to science and these poxviruses have been isolated from different species of birds, insects, reptiles, marsupials and mammals. Poxviruses that may cause human disease include the smallpox (or variola) virus and molluscum contagiosum virus.
Mpox has been historically reported in several countries in West and Central Africa. This distribution of mpox virus is attributed to the fact that it is naturally harboured by animals found in this part of Africa. It is believed that rodents, most likely certain species of squirrels found in the deep-forested areas of this region in Africa, may be the natural host of the virus.
Mpox virus infections in humans have historically been noted in these countries, albeit rarely. However, since the 1990s, there has been an increasing number of cases diagnosed in endemic countries. This has in part, been attributed to the the discontinuation of smallpox vaccination after smallpox was successfully eradicated. Smallpox vaccination provided cross-protection against mpox virus infection, but over time and following the cessation of vaccination, there has been waning immunity in the vaccinated and a growing population who have not been vaccinated before. Other factors may increase the risk of zoonotic spillover of the virus, and recent mpox epidemics have been characterized by sustained human-to-human transmission.
The emergence of mpox in West and Central African countries was noted prior to the advent of the multi-country mpox outbreak in 2022. During the multi-country mpox outbreak, from May 2022 until September 2024 have resulted in the detection of nearly 110 000 laboratory confirmed mpox cases from 123 countries. The multi-country outbreak has been associated with the Clade IIb (lineage B.1) variant of the mpox virus. Since 2023, an alarming rise in the number of mpox cases have been reported from the DRC. In this instance, the outbreak is associated with Clade Ib variant of the mpox virus. Since September 2024, the Clade Ib variant has been detected beyond the borders of the DRC.
In 2022, at the first peak of the multi-country outbreak, a total of five cases of mpox were diagnosed in South Africa. The Clade IIb B1.7 mpox virus was found associated with these cases. This variant of the mpox virus was widely circulating in a number of countries at that time. Since May 2024 up to 23 October 2024, a total of 25 cases of mpox were diagnosed in South Africa. A total of three deaths were reported. All but one case reported no travel history outside of South Africa which implies local transmission of the virus. In all of the cases with no travel history, Clade IIb B1.20 mpox virus variant was found. Clade IIb B1.6 was found for a traveler returning from Peru and diagnosed with mpox on his return to South Africa. No cases of Clade Ib mpox cases have been reported in South Africa (up to 23 October 2024).
Travel advisory:
The WHO recommends no travel restrictions to countries affected with mpox, including the DRC. Persons with suspected or confirmed mpox and any individuals showing signs and symptoms compatible with mpox should refrain from non-essential travel and close contact with others.
Stay informed with the latest national mpox statistics—visit the NICD mpox dashboard here.