What you need to know about the virus that causes monkeypox.
Video / AP / Getty
New Zealand has just become one of more than 50 countries to record cases of monkeypox in an outbreak that took off two months ago. But experts stress that we shouldn't worry. Science reporter Jamie Morton explains.
Its arrival was inevitable
New Zealand's first recorded case of monkeypox – a recently-returned Aucklander aged in their 30s who's now isolating at home – hardly came as a surprise to health experts.
Since a cluster of the viral disease was confirmed in the UK back in May, the outbreak has grown to more than 8000 cases and spread to 57 countries as far-flung as Venezuela, Iceland, Latvia and South Korea.
"Once we reached that many cases in the world, and Australia was recording 20 of them, we were always going to see it in New Zealand ... I don't think there was any ever question of that," Otago University epidemiologist Professor Michael Baker said.
How the global outbreak began remains unclear – and its emergence in the UK marked the first time that what was considered a reasonably rare, tropical disease had spread widely outside rainforest areas in Central and West Africa.
With the World Health Organisation recording a 77 per cent jump in cases in the past week - and now considering whether the outbreak should be called a public health emergency - this global flare-up appeared to be only getting started.
More cases were likely to pop up in New Zealand, too - but experts nonetheless expect there's little danger to the public here.
"What would make it more important to New Zealand was if we had local transmission," Baker said.
"But at the moment, this is effectively an imported disease and we'd put it in the general category of tropical infection.
"For global health authorities, the main concern currently is that it becomes another disease of low and middle-income countries that they don't really need."
Your risk is very low
Monkeypox, which was first observed in humans back in the 1970s, in a 9-year-old boy in Congo, is known to come in two main forms.
There's a deadlier type that comes with a fatality rate of about 10 per cent, and another, less severe type that kills only about 1 per cent of those it infects.
We, fortunately, don't appear to be dealing with the former, and genomic sequencing has linked the virus behind this outbreak to a West African clade that appeared in earlier international outbreaks.
While severe cases could occur, it was currently considered a self-limiting disease, with flu-like symptoms such as fever, along with rashes, lasting from two to four weeks.
Because monkeypox had a relatively long incubation period – six to 13 days – it was also considered less contagious, while tell-tale symptoms like large, visible lesions made inadvertent transmission less likely.
"I think the public should not be at all concerned about this," Baker said.
"It's still an unlikely event that most New Zealanders would encounter it in the short to medium term."
Dorsal surfaces of the hands of a monkeypox patient, showing a rash during the recuperative stage. Photo / CDC via AP
Otago University infectious diseases physician Professor Kurt Krause also said people didn't need to panic.
"People will need to be on the lookout if they may have been exposed," he said.
"And affected people will need to isolate, but almost everyone affected will recover very well."
It's very different to Covid-19
Baker pointed out that, next to the far more transmissible Covid-19 – of which another 7461 cases were reported on Sunday, along with eight linked deaths and 662 hospitalisations – monkeypox's public risk stood all the more smaller.
As its name implies, monkeypox is a pox virus and part of the same, diverse family of oval-shaped viruses that includes the notorious smallpox.
Since smallpox was globally eradicated just over four decades ago – it remains the only human disease we've managed to wipe out from nature - monkeypox has become the most common cause of pox infections.
Some scientists suspect our waned immunity to a long-absent smallpox may have raised our vulnerability to monkeypox.
While the Sars-CoV-2 virus that causes Covid-19 is also zoonotic – or stemming from animals – it's much unlike monkeypox.
One of the biggest differences is monkeypox is a double-stranded DNA virus, and thus has a larger and more stable genome than coronavirus, a single-stranded RNA virus.
Associate Professor Fasséli Coulibaly, a microbiologist at Australia's Monash University, earlier noted pox viruses were among the most complex viruses able to infect humans - and were experts at subverting defence systems put up by their host.
"Yet, they are a bit like the elephants of the virus world - their structure and replication make them easier to aim at than smaller, moving targets."
Sex may be a factor in spread
The Ministry of Health said cases of monkeypox outside endemic countries have primarily been identified among gay and bisexual men and men who have sex with men, and international cases have been clustered around events where this occurs.
Monkeypox had not previously been documented to have spread through sex, but it could be transmitted through close contact with infected people's body fluids and clothing.
Covid-19 Response Minister Dr Ayesha Verrall said monkeypox lesions were distinctive but the disease could incubate undetected at first.
"It can be transmitted by close physical contact or by droplets ... but the suspicion is that the cluster that's emerging in Europe has been spread by sexual contact."
Dr Michael Skinner, a virologist at Imperial College London, told the Associated Press in May it's still too early to determine how the men in the UK were infected.
"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."
A monkeypox PCR test is available in New Zealand labs and is what has been used to detect the first case. Photo / Getty Images
The US Centers for Disease Control and Prevention (CDC) also said early data suggest that gay, bisexual, and other men who have sex with men make up a high number of cases.
"However, anyone who has been in close contact with someone who has monkeypox is at risk."
Fortunately, the world does have effective vaccines available for monkeypox: the second and third-generation smallpox vaccines, both of which are "live virus" vaccines using the vaccinia virus.
The ministry was now working with Pharmac to explore options for access to smallpox vaccines that could be used as part of the targeted prevention of the spread of monkeypox in certain situations.
Anti-viral drugs were also being developed.
In the meantime, the ministry advised people to practise good hand hygiene after contact with infected people or animals, and avoiding contact with any materials, like bedding, that have been in contact with them.
People returning from overseas with any blister-like sores on their bodies, or experiencing a rash-like illness, were also asked to seek healthcare advice.
While the monkeypox risk might be currently deemed low, scientists still say health authorities should be paying close attention.
"Monkeypox and Covid-19 are different diseases and spread through somewhat different pathways, but at a personal level, personal hygiene measures and protection with masks are super important for both diseases, especially as Covid-19 cases will continue to rise," Canterbury University epidemiologist Associate Professor Arindam Basu said.
"Being watchful about contacts, keeping a diary, and getting the tests at the first instances of common cold-like symptoms may be helpful."
