MADRID (AP) -- Health officials in Spain reported seven cases of monkeypox and Portugal updated its number of confirmed cases to 14 on Thursday as an outbreak of a viral disease typically limited to Africa expanded in Europe.
In Spain, all of the reported cases to date involved men in Madrid, officials said. Health officials are currently testing another 22 suspected cases, said Antonio Zapatero of the regional health department.
"It's possible that more cases will emerge in the coming days," Zapatero told Spanish radio network Onda Cero.
Officials said that all of the cases identified so far were mild and that the infections appeared to be linked to close contact among two chains of transmission. No details were given as to whether the men had traveled to Africa or whether the cases were connected to other reported cases across Europe.
Portuguese authorities said on Thursday that the 14 cases confirmed in the country all were reported in the area surrounding the capital city of Lisbon.
Meanwhile, the tally of confirmed cases in Britain rose to nine. Britain's Health Security Agency said Wednesday that recent cases reported this week had been seen "predominantly in ... men who have sex with men," though it noted that it was unclear how exactly people had gotten infected.
In Rome, the Lazzaro Spallanzani Hospital said Thursday it had confirmed one case of monkeypox in a patient who had recently traveled to Spain's Canary Islands. Sweden's public health agency also reported one case Thursday, saying it remained unclear how the patient became infected.
Monkeypox has not previously been documented to have spread through sex but can be transmitted through close contact with infected people, their clothing or bedsheets.
The U.S. state of Massachusetts on Wednesday reported one case of monkeypox in a man who recently traveled to Canada, prompting officials to probe potential links to the outbreak in Europe.
The European Center for Disease Prevention and Control said Thursday that the probability of transmission without close contact is low. But it warned that "the likelihood of further spread of the virus through close contact, for example during sexual activities, is considered to be high."
It recommended that authorities and community organizations raise awareness of the outbreak among men who have sex with other men or who have casual sex or multiple partners.
Suspected cases should be isolated, it said, and the smallpox vaccine should be administered to high-risk close contacts.
Monkeypox typically causes fever, chills, a rash and lesions on the face or genitals resembling those caused by smallpox. A vaccine developed against smallpox has been approved for monkeypox, and several anti-virals also appear to be effective.
Most people recover from monkeypox within weeks, but the World Health Organization says the disease is fatal for up to 1 in 10 infected people. Sporadic cases of monkeypox have been seen previously in countries including Britain and the U.S., but nearly all have been in people who were likely infected during their travels in Africa.
