Belgium has become the first country in the world to announce a compulsory monkeypox quarantine as cases continue to spread rapidly. 

Under the new rules, those who test positive to the virus in Belgium will be required to undergo a 21-day mandatory quarantine in a bid to stop the spread of infections. 

The first case in Belgium was diagnosed on Friday, before two more were confirmed, followed by a fourth on Saturday. 

All three are believed to be linked to the recent Darklands fetish festival in Antwerp, while cases in Spain are believed to be connected to a superspreader event at an adult sauna. 

"There's reason to assume that the virus has been brought in by visitors from abroad to the festival after recent cases in other countries," Darklands festival organisers said in response to the outbreak. 

This 2003 electron microscope image made available by the Centers for Disease Control and Prevention shows a monkeypox virion. Photo / File 

Belgian public health doctor and Professor of Virology Marc Van Ranst said on Twitter it was "important that everyone who was present at the Darklands festival remains vigilant for any symptoms", adding the scale of the outbreak was becoming "increasingly clear". 

"This is unheard of before with monkeypox viruses," he said. 

Over the weekend, the World Health Organisation announced there had been 92 confirmed cases so far across 12 different countries, including Australia, Belgium, Canada, France, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, the UK and the USA. 

Since then, new cases have been confirmed in Israel, Austria and Switzerland, while in the UK, Public Health England's Dr Susan Hopkins told the BBC yesterday authorities were "detecting more cases daily". 

This 2003 electron microscope image shows mature, oval-shaped monkeypox virions, left, and spherical immature virions, right. Photo / File 

Hopkins also warned the public to "be alert" and said children were more likely to fall seriously ill from the virus. 

"We do know from reports from Africa, where the disease has circulated in outbreaks over many years, certain individuals are much more at risk of severe disease, including immunosuppressed individuals or young children. 

"In adults, it is relatively mild. 

"Clearly, this is a new infectious disease that we haven't seen in our community before. We will need to learn a lot about it over the coming weeks." 

Meanwhile, infectious diseases expert Sanjaya Senanayake told Sunrise on Monday morning that while the disease was "not on the same scale as Covid", Australians should be on alert, with at least two cases confirmed on Australian shores so far. 

"It tends to spread with really close contact and respiratory contact is less of an issue," he said. 

"It also doesn't send many people to hospital, a different level to Covid. 

"Anybody can potentially get this, but with this current outbreak it seems to largely be among men and those who have an intimate physical contact." 

This 1997 image provided by CDC, shows the right arm and torso of a patient, whose skin displayed a number of lesions due to what had been an active case of monkeypox. Photo / File 

Senanayake said illness tended to last for around five days and symptoms include "terrible headaches, muscle aches and fevers" as well as a rash that "can cover the body". 

"Interestingly it comes from the same family as smallpox and I as an infant had a smallpox vaccine, there are still supplies around so you can give the smallpox [vaccine] to close contacts and [that] is what they are doing in the UK." 

He added that antiviral medications could also help patients. 

Senanayake's warning comes after NSW chief health officer Dr Kerry Chant urged gay men to be particularly vigilant last week. 

"We know it's transmitted by that close skin to skin contact – you can be infectious and that close droplet contact in a very sort of close prolonged way," Chant said. 

"We're particularly urging men who are gay or bisexual, or men who have sex with men, to be aware of any unusual rashes or lesions and to contact by phone a sexual health clinic or GP without delay if they have any concerns. 

"It is important to be particularly vigilant if you returned from overseas from large parties or sex on premises venues overseas." 

What is monkeypox? 

Belonging to the same family as smallpox, the world's first human monkeypox case was discovered in 1970 in the Democratic Republic of Congo. 

The virus spreads through the body via the bloodstream, with symptoms typically appearing one or two weeks after infection. 

Symptoms may include skin lesions as well as flu-like symptoms such as fevers, headaches and shortness of breath. 

The smallpox vaccine can provide protection for both illnesses. 

- by Alexis Carey, news.com.au