Mpox Updates

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 from several countries from West and Central Africa (WCA). This distribution of mpox virus is attributed to the fact that it is naturally harboured by animals that are 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 of Africa, may be the natural host of the virus. Mpox infections in humans have historically been noted in these countries albeit at a relatively low level.

In countries where the natural animal host of the virus are found, the mpox virus may be spread from handling infected bush meat, an animal bite or scratch, body fluids and contaminated objects. Cases of mpox spreading through animals, outside of the endemic areas, are very rare, but may involve the exotic pet trade or potentially through contact with infected animalderived materials such as skins and leather. Person-to-person transmission involves close contact with an infected person or materials that have been contaminated by an infected person.

The incubation period (time from infection to symptoms) for mpox is on average 7−14 days but can range from 5−21 days. Initial symptoms include fever, headache, muscle aches, backache, chills and exhaustion. Within 1-3 days of onset of disease, blister-like lesions will develop on the face, the extremities including soles of the feet and palms of the hands. The lesions may however occur on other parts of the body.

A new variant of the MPXV, named “clade 1b,” emerged during epidemiological week 16 of 2024 (14 – 20 April 2024) in Kamituga, a mining enclave within the DRC. This variant exhibits heightened transmissibility, mainly through sexual contact, raising concerns about its potential to cause a pandemic.

Recent Updates
Most frequent questions and answers about Mpox

An infected person is contagious from the onset of the rash/lesions through the scab stage. Once all scabs have fallen off, a person is no longer contagious. It is currently not known how long viable virus may persist for example in semen.

Mpox is diagnosed by a healthcare worker in consideration of the clinical presentation of the patient. The nature of the rash would be the most telling sign.
However, the healthcare worker will consider possible exposures for the case with the consideration that the likelihood of contracting mpox is very low. Many other diseases, such as chickenpox, may cause similar rashes and are more common.

Samples can be tested at the National Institute for Communicable Diseases or
private pathology services (contact your preferred service for more information) to
confirm a diagnosis of mpox. For more information on laboratory testing of mpox,
refer to the disease index on the website.

Treatment is supportive, as with most viral infections. Most human cases of mpox virus infection do not require any specific treatment and the disease resolves on its own. There are anti-viral drugs that a clinician may consider to use for treatment of more severe cases of mpox on a case-by-case basis.

Mpox outbreaks can be controlled by diagnosis and laboratory confirmation of cases. This allows for contact tracing and monitoring to enable the pro-active recognition of any other linked cases of mpox. It is recommended that confirmed cases of mpox isolate to ensure that risk of transmission is minimized. Isolation may be through self-isolation at home if circumstances allow, but cases may be isolated in hospital if so required.

The World Health Organization did not recommend massvaccination as a measure to contain the outbreak. Nonetheless, the United States and certain European nations are providing smallpox vaccination to high-risk households and identified close contacts up to 14 days after exposure and gay and bisexual men with multiple sex partners.

The implications for South Africa are that the risk of importation of mpox is a reality as lessons learnt from COVID-19 have illustrated that outbreaks in another part of the world can fast become a global concern. The WHO has not recommended any travel restrictions and are working with the affected countries to limit transmission and determine sources of exposure.

The risk of mpox to the South African population remains low, given the low transmissibility of the virus. Nevertheless, South Africa has diagnosed five cases from the multi-country outbreak as of 14 March 2023, all men between 28 and 41 years of age, three of which with recent travel from Switserland, Spain and Netherlands.