The rise in monkeypox cases in Spain has been linked to a superspreader event at a Madrid adult sauna.
Madrid's cabinet minister for health of the community, Enrique Ruiz Escudero, said of the 30 monkeypox cases detected in the country, many were traced to the sauna in the capital.
Monkeypox has also been detected in the UK, with the total now standing at 20 after another 11 were announced on Friday.
Health officials said a "notable proportion" of the cases had been identified in gay and bisexual men, while three cases in Belgium were linked to fetish festival Darklands in Antwerp.
State health authorities in Australia are also warning people to be vigilant after two cases of monkeypox were confirmed in NSW and Victoria.
Both a man in his 40s in NSW and man in his 30s in Victoria recently travelled to Europe and are currently isolating.
It is believed the mild illness is transmitted through air droplets, close bodily contact or sharing contaminated linens or objects.
Symptoms include fever, headache, muscle aches and exhaustion.
People should be 'particularly vigilant': NSW Chief Health Officer
NSW Chief Health Officer Dr Kerry Chant said monkeypox was a rare virus and did not spread easily between people.
She said a large number of overseas cases were among gay and bisexual men and urged those men to "be aware of any unusual rashes or lesions" and to contact their GP or a sexual health clinic if concerned.
Dr Chant said people should be "particularly vigilant" if they had returned to Australia after attending large parties or sex-on-premises venues overseas.
NSW-based sexual health organisation ACON urged gay, bisexual and men who have sex with men to remain vigilant and follow health advice.
"It's important we remember that viruses do not discriminate," said ACON CEO Nicholas Parkhill on Friday.
"We particularly urge those who attended dance parties, sex parties or saunas in Europe to be vigilant for compatible symptoms."
Australia joins Italy, Sweden, the United Kingdom, Spain, Portugal and the United States as nations dealing with recent cases.
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