Hundreds more monkeypox cases have been reported outside of the African nations where the disease is generally found, according to the WHO, which warns that the virus is likely spreading under the radar.
"Investigations are ongoing, but the sudden appearance of monkeypox in many countries at the same time suggests there may have been undetected transmission for some time," said World Health Organization chief Tedros Adhanom Ghebreyesus told reporters.
More than 550 confirmed cases of monkeypox have been validated in 30 countries outside of the west and central African countries where it is endemic since Britain first reported a confirmed case on May 7, according to the WHO.
The development of so many cases over most of Europe and other countries where it has never been seen before, according to the UN's top monkeypox specialist Rosamund Lewis, "is clearly a cause for concern, and it does suggest undetected transmission for a while".
"We don't know if it is weeks, months or possibly a couple for years," she said, adding that "we don't really know if it is too late to contain".
Monkeypox is linked to smallpox, a disease that killed millions of people each year before being eliminated in 1980.
Fight stigma
Monkeypox, on the other hand, is far less severe and spreads by intimate contact, with symptoms including a high fever and a blistery chickenpox-like rash that clears up after a few weeks.
Although scientists emphasise that there is no proof that monkeypox is transmitted sexually, the majority of cases have been documented among males who have sex with men.
"Anyone can be infected with monkeypox if they have close physical contact with someone else who is infected," Tedros explained.
He asked everyone to help "fight stigma, which is not just wrong, it could also prevent infected individuals from seeking care, making it harder to stop transmission".
He also stated that the WHO was "urging affected countries to widen their surveillance".
Lewis emphasized that "that we collectively all work together to prevent onward spread", of the disease by tracking contacts and isolating infected persons.
Vaccines produced for smallpox have been shown to be 85 percent effective in preventing monkeypox, but supplies are limited.
The WHO is not advocating for mass vaccination, but rather for targeted immunization in some contexts to safeguard health professionals and those who are most vulnerable to illness.
Lewis pointed out that monkeypox cases have been rising in endemic regions, where thousands become ill each year, with roughly 70 deaths from the virus documented so far this year across five African countries.
Monkeypox has a low mortality rate, and no deaths have been documented in cases discovered outside of endemic areas thus far.
While no deaths have been documented, Maria Van Kerkhove, WHO's expert on emerging diseases, cautioned that this might change if the virus spreads to more susceptible communities.
