Situation Update: Monkeypox

The National Institute for Communicable Diseases (NICD), a division of the National Health Laboratory Service, confirms that there are currently no monkeypox cases in South Africa. On 13th May 2022, the World Health Organization (WHO) was notified of two laboratory-confirmed cases and one probable case of monkeypox, from the same household, in the United Kingdom. On 15th May, four additional laboratory-confirmed cases were reported amongst sexual health services attendees presenting with a vesicular rash illness in men practising sex with men. Since then, 15 countries have collectively reported more than 140 cases (see table).

Of the cases with available information, males accounted for more than 70%, mostly aged between 20-55 years, and have been detected through sexual health services. Most cases are mild and present with lesions on the genitalia or peri-genital areas. Additional symptoms include rash, fever, painful lymph nodes, and oral ulcers. Possible transmission between sexual partners may occur due to contact during sex with infectious skin and mucosal (including oral) lesions, as sexual transmission of monkeypox has not yet been proven. Genital lesions have previously been uncommon and reflect a unique aspect of this outbreak.

The first case in the current outbreak was a traveller who returned to the United Kingdom from Nigeria, a monkeypox endemic area, on 4th May 2022. Clinicians confirmed that the patient had monkeypox three days later. Investigations have been unable to link that case to any of the other cases detected to date, suggesting that there have been multiple introductions of the virus into the United Kingdom and other countries, with cases potentially having gone undetected till now. A preliminary genome sequence from a confirmed Portuguese case indicates that the virus is the West African strain (reduced mortality of 1% compared to the 10% of the Congo Basin strain) and is most closely related to viruses associated with the exportation of monkeypox from Nigeria to the United Kingdom, Israel, and Singapore during 2018-2019.

Milder cases of monkeypox may go undetected and represent a risk of person-to-person transmission. There is likely to be little immunity to the infection in those travelling or otherwise exposed, as endemic disease is usually geographically limited to parts of West and Central Africa. Although monkeypox, which is related to smallpox (which has been eradicated), sporadically causes small outbreaks, transmission is believed to be inefficient as close contact is required. Thus the current outbreak is unlikely to progress to being a global emergency. Monkeypox is usually a self-limiting illness, and most cases will recover within a few weeks without treatment. However, severe disease may be observed in young children, pregnant women, and individuals who are immunocompromised. Historically, vaccination against smallpox was shown to be protective against monkeypox. Contact tracing is ongoing in the countries reporting cases, and contacts are being assessed based on their level of exposure and followed up through active or passive surveillance for 21-days from the date of last exposure to a case. Smallpox vaccination is being offered to higher risk contacts, but global vaccine availability is a challenge.

What are the implications for South Africa?

“The implications for South Africa are that the risk of importation of monkeypox 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,” says NICD Executive Director, Prof Adrian Puren. The WHO has not recommended any travel restrictions and is working with the affected countries to limit transmission and determine sources of exposure. He adds that for any persons entering South Africa, any illness during travel or upon return from an endemic area should be reported to a healthcare professional, including information about all recent travel, immunisation history and contact with any known cases.

Residents and travellers to endemic countries should avoid contact with sick animals that could harbour monkeypox virus, such as rodents, marsupials, and primates and should refrain from eating or handling wild game. A good history is essential to rule out other differential diagnoses, including malaria. Puren concludes that residents and travellers to countries affected in the current outbreak, should report any illness to a healthcare professional, including information about all recent travel and attendance of mass gathering events, festivals and parties, and contact with any known cases.  The importance of hand hygiene by using soap and water or alcohol-based sanitiser should be emphasised.

“The NICD is equipped to test for monkeypox as the Centre for Emerging, Zoonotic and Parasitic Diseases (CEZPD) has a diagnostic polymerase chain reaction (PCR) in place and electron-microscopy capacity,” comments Dr Jacqueline Weyer from the Special Viral Pathogens Division at the CEZPD. Additionally, Weyers highlights that the NICD Sequencing Core Facility will work to provide sequencing analysis rapidly, should a case be identified to determine relatedness to the current outbreak strain. The NICD will continually assess the risk for local introduction and/transmission in collaboration with the National Department of Health and the WHO in line with the International Health Regulations.

Table. Countries reporting monkeypox cases, May 2022

For more information on monkeypox visit https://www.nicd.ac.za/diseases-a-z-index/monkeypox/

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