There have been dozens of cases reported in recent weeks among populations not typically vulnerable to the disease.
It was discovered in 1958, after outbreaks occurred in monkeys kept for research, according to the Centers for Disease Control and Prevention.
Within Africa, 11 countries have reported cases since 1970, when the first human case was identified in a 9-year-old boy in the Democratic Republic of Congo.
“Most cases presented with lesions on the genitalia or peri-genital area, indicating that transmission likely occurs during close physical contact during sexual activities,” the European Center for Disease Prevention and Control said on Friday.
There have been 38 cases worldwide this year as of Thursday, including 37 with no history of travel to endemic countries, according to the European Centre for Disease Prevention and Control.
None of the infected people have died, according to the European Centre for Disease Prevention and Control.
This is the first time that chains of transmission were reported in Europe without links to West or Central Africa, according to the European Center for Disease Prevention and Control.
The likelihood of the virus being spread during sexual contact is high, but the risk of transmission from other forms of close contact is low, the European Center for Disease Prevention and Control said