This 2003 electron microscope image made available by the Centers for Disease Control and Prevention shows mature, oval-shaped monkeypox virions, left, and spherical immature virions, right, obtained from a sample of human skin associated with the 2003 prairie dog outbreak. A leading doctor who chairs a World Health Organization expert group described the unprecedented outbreak of the rare disease monkeypox in developed countries as "a random event" that might be explained by risky sexual behavior at two recent mass events in Europe. (Cynthia S. Goldsmith, Russell Regner/CDC via AP, File)
LONDON (AP) — Health authorities in Europe, North America, Israel and Australia have identified more than 100 cases of monkeypox in recent days.