Cape Town - Monkeypox has been confirmed in 23 non-endemic countries in the last three weeks.
As of May 26, a total of 257 monkeypox cases have been laboratory confirmed and a further 120 suspected cases were reported to the World Health Organization.
“The outbreak is unprecedented as it presents the first outbreak of monkeypox involving several non-endemic countries simultaneously. It is also already the largest outbreak of monkeypox outside of endemic states to date,” the The National Institute for Communicable Diseases (NICD) said in its monthly communique.
The epidemiological links of cases are still under investigation but most cases reported to date have been found in men that have sex with men.
“There (is) also evidence suggesting the involvement of large social gatherings that may have served as super-spreader events,” the NICD said.
Genetic analysis of the viral genomes associated with some of the cases indicate the circulation of the Western African clade of monkeypox virus with the viruses most closely related to those reported in Nigeria since 2018.
The hypothesis is that the outbreak is caused by a single source introduction, likely a traveller to an endemic area such as Nigeria, with community spread affecting primarily men who have sex with men, the NICD said.
The zoonotic disease is caused by infection with monkeypox virus, endemic to the deep-forested regions of a number of Western and Central African countries including Democratic Republic of Congo, Nigeria, Central African Republic, Cameroon, Ghana, Sierra Leone, Liberia, South Sudan and Ivory Coast.
The first human cases of monkeypox were reported in the 1970s and it has remained a relatively rare disease of humans since.
In the first five months of 2022, the Democratic Republic of Congo reported more than 1 200 cases of monkeypox, while Nigeria reported nearly 50 cases.
Cases of monkeypox outside of endemic areas include the 2003 outbreak of monkeypox in the US which was linked to the exotic pet trade.
Since 2018, six cases of monkeypox in travellers have been noted in Israel, the UK, Singapore and the US. A secondary case of transmission was noted only in one of these cases and involved a health care worker. No fatalities were recorded in these cases.
“Monkeypox is typically a mild self-limiting disease. The incubation period following exposure ranges from 5-21 days. Initial signs and symptoms include fever, intense headache, back pain, malaise and intense weakness,” the NICD said.
A rash develops 1-3 days following onset of illness, usually accompanied by a fever.
The rash involves blister-like skin lesions often found on the face and extremities, including the soles of the feet and palms of the hands. The lesions may also be found on the mouth, genitalia and eyes.
Most cases will resolve in 3-4 weeks. Severe cases in endemic countries have been mostly reported in children. It is also anticipated that immuno-compromised individuals may be predisposed to more severe disease.
“Vaccines previously used for smallpox immunisation provides up to 85% cross-protective immunity to monkeypox. Smallpox vaccination was discontinued in most countries in the 1980s due to the successful eradication of smallpox. Some level of immunity is therefore expected in the population aged 40-50 years depending when smallpox vaccination ceased in the country and onwards.
"Stocks of smallpox vaccines are available in international stockpiles and it may be that large scale production may be started up again,” the NICD said.
Isolation of confirmed cases is recommended and the requirement of in-hospital isolation may be considered on a case-by-case basis.
Cape Times