Public health officials believe a second person in Philadelphia has contracted monkeypox.

The individual tested positive for infection with an orthopox virus, the category that includes monkeypox, the Pennsylvania Department of Health said Wednesday. The new case is presumed to be monkeypox, as that’s the only orthopox virus now in circulation, but specimens have been sent to the CDC for confirmatory testing.

The city’s two cases are among 72 confirmed and probable cases of monkeypox nationwide, according to the CDC.

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Philadelphia’s first case was confirmed June 3. The city Department of Public Health said it was working with that patient to identify any close contacts for possible treatment, but did not respond to an inquiry about the second case. The city’s second case was first reported by NBC10.

Physicians say the virus spreads mainly through close, skin-to-skin contact, though the World Health Organization told CBS News this week that scientists are studying whether it might also be transmitted through semen. The virus infects thousands of people each year in Africa, but its spread outside that continent this year is unusual.

The virus spreads much less easily than COVID-19, and severe consequences are rare. The public health risk is considered low.

Symptoms include fever followed by a rash, with rounded, flat lesions that later protrude from the skin.