On 13 May, the World Health Organization was notified of two confirmed cases and one probable case of monkeypox in the UK. The number of cases has now risen to nine.
This has raised some alarm, because historically only eight cases have been detected in the UK, the first of those in 2018.
Cases have also been detected in Spain (more than 20) and Portugal, resulting in the largest monkeypox outbreak in Europe to date. So should Australia be worried?
What are the symptoms?
The monkeypox virus leads to flu-like symptoms including fever, body aches and chills, and causes a distinctive rash in the form of lesions that often start on the face.
How concerned should Australia be?
According to Peter Collignon, professor of infectious disease at the Australian National University, there is no cause for alarm in Australia. Even if a case were to be identified, “it’s not highly transmissible from person to person,” he said.
Animals are the reservoir for the virus, with rodents believed to be the main source. It seems it is mostly spread to humans through interaction with infected animals.
Risk factors associated with human-to-human transmission include sleeping in the same room or bed, living in the same household, or drinking or eating from the same dish as an infected person.
“People need to remember we actually have other pox viruses in Australia already, such as Orf, a highly contagious virus among sheep that occasionally spreads to humans, mostly the farmers who work with them,” Collignon said. “But we don’t see significant outbreaks of that in humans who become infected.
“Pox viruses are not new. And monkeypox is not like Covid, with a high transmission rate.”
When was monkeypox first identified?
The first case of monkeypox anywhere was recorded in 1970 in the Democratic Republic of the Congo in central Africa, during intense efforts to find and eliminate smallpox.
The cases in the UK are unusual because monkeypox is an extremely rare virus outside parts of Africa, and does not spread easily between people.
Since the UK cases were identified, 23 suspected cases have been identified in Spain, and five in Portugal, where at least 20 further cases are suspected.
When the virus appears outside Africa, it is because someone travelled to an endemic region, became infected and returned home. But in the UK, no source of infection has been confirmed for eight of the cases, despite contact-tracing efforts.
The first of the new cases found in the UK, detected on 7 May, had travelled to Nigeria where they are believed to have contracted the illness. But two other clusters of cases have emerged in the UK since, with no link established with that first case.
“Based on currently available information, infection seems to have been locally acquired in the United Kingdom,” the WHO said on Thursday. “The extent of local transmission is unclear at this stage and there is the possibility of identification of further cases.”
Rising transmission flagged
There are two strains of monkeypox; a Central African strain with a fatality rate of 10.6%, and a West African strain with a much lower mortality rate of between 1% and 3.6%. The latter is the strain identified in the UK.
But there have been warnings that countries outside Africa have become too complacent about the virus due to its rarity. A study published in the journal PLOS Neglected Tropical Diseases in February found monkeypox cases, though rare, are rising.
The study authors reviewed monkeypox data from many countries and studies, and found “an escalation of monkeypox cases, especially in the highly endemic DRC, a spread to other countries, and a growing median age from young children to young adults”.
“These findings may be related to the cessation of smallpox vaccination, which provided some cross-protection against monkeypox, leading to increased human-to-human transmission,” the study found.
“The appearance of outbreaks beyond Africa highlights the global relevance of the disease.”
The authors urged for increased worldwide surveillance and detection of monkeypox cases to understand its changing epidemiology, and described it as a “resurging disease”.
Are there any theories yet about how transmission is occurring in the UK?
One of the clusters in the UK has been among men who have sex with men, but experts have warned against labelling it a sexually transmitted disease.
Dr Michael Skinner, with the Imperial College London, said, “Although this is the first time we have seen monkeypox in this group, that may just be because previously the numbers of cases have been low and so specific groups are less likely to have been captured in the statistics.”
“By nature, sexual activity involves intimate contact, which one would expect to increase the likelihood of transmission, whatever a person’s sexual orientation and irrespective of the mode of transmission,” he said.