Overview
What is mpox?
Mpox (previously named monkeypox) is a viral disease caused by infection with the monkeypox virus (MPXV) (also referred to as the mpox virus), a member of the genus Orthopoxvirus in the family Poxviridae. Mpox has been historically reported in several countries in West and Central Africa, attributed to being 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 may be the natural host of the virus.
The MPXV infections in humans have historically been noted in these countries, albeit rarely. However, since the 1990s, there has been an increasing number of confirmed mpox cases in certain endemic countries. This has in part, been attributed to the discontinuation of smallpox vaccination around 1980 (different countries stopped vaccinating a different times), after smallpox was successfully eradicated. Smallpox vaccination provided cross-protection against MPXV infection. However, over time, and following the cessation of smallpox vaccination, there has been waning immunity in the vaccinated and a growing unvaccinated population. Additionally, it may be that other factors have and are increasing the risk of zoonotic spillover of the virus, but this is not well understood yet. The recent mpox epidemics have been characterized by sustained human-to-human transmission which has resulted in the emergence of novel variants of the virus.
The emergence of mpox in West and Central African countries was noted prior to the advent of the multi-country mpox outbreak in 2022. Since the beginning of the multi-country mpox outbreak in May 2022, nearly 129,172 laboratory-confirmed mpox cases from 130 countries have been reported by 10 March 2025. The multi-country outbreak has been associated with the Clade IIb (lineage B.1) variant. Since 2023, an alarming rise in the number of mpox cases has been reported from the Democratic Republic of Congo (DRC), with a new variant , namely the Clade Ib variant emerging due to human-to-human spread of the virus. Since September 2024, the Clade Ib variant has spread beyond the DRC to other African countries and outside the African continent.
In 2022, at the first peak of the multi-country outbreak, a total of five laboratory-confirmed mpox cases were reported in South Africa, associated with the Clade IIb B1.7 variant. This variant was widely circulating in multiple countries at that time as three of the five cases confirmed history of international travel. In 2024 a total of 25 laboratory-confirmed mpox cases, including three deaths, were reported in South Africa between May to October 2024. All but one case reported no travel history outside of South Africa which implies local transmission. The Clade IIb B1.20 variant was found in all the cases without international travel history, whereas Clade IIb B1.6 was found in one case who returned from Peru before developing the illness. No cases of Clade Ib variant were reported in South Africa in 2022 and 2024.
Since February 2025, and as of 24 March 2025, seven laboratory-confirmed mpox cases were reported in Gauteng Province, associated with the Clade Ib variant. The first case had a recent travel history to Kampala, Uganda, where there is an ongoing (at the time of writing) mpox outbreak associated with the Clade Ib variant. This case was associated with to mpox cases, which involved close contacts of the index case. A fourth case, from the same geographical area in the province was detected but not linked to the first cluster of three cases. A further three cases of mpox were linked to the former case. In summary, two clusters of Clade Ib mpox have been identified during this period. These cases present the first detected occurrence of mpox Clade Ib in South Africa.
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.
