The WHO has said it is investigating the fact that many cases reported were people identifying as gay, bisexual or men who have sex with men. Most initial cases of the disease have been among men who have sex with men and sought treatment at sexual health clinics, Kluge said, adding “this suggests that transmission may have been ongoing for some time”. The health official warned that transmission could be boosted by the fact that “the cases currently being detected are among those engaging in sexual activity”, and many do not recognise the symptoms. “All but one of the recent cases have no relevant travel history to areas where monkeypox is endemic,” he added. But over recent weeks cases have been detected in European countries including Portugal and Sweden as well as the United States, Canada and Australia, Kluge said, calling the spread “atypical”.