NEW YORK (PIX11) — One patient has tested positive for orthopoxvirus, New York City health officials said Friday. Orthopoxcrisus is a family of viruses, which includes monkeypox.

The Centers for Disease Control and Prevention will confirm whether or not the positive patient has monkeypox. In the meantime, the New York City Department of Health is treating the cases as a “presumptive positive.”

A second patient tested negative.

The patient is isolating, officials said. Contact tracing is being performed in the city to identify any potential contacts to the patient.

The Department of Health said masks can protect against the virus. Anyone who experiences flu-like symptoms along with lymph node swelling and rashes on the face and body should contact a doctor, officials said.

Monkeypox is rare but can spread through close contact with an infected person or animal, officials said. That includes via respiratory droplets usually after prolonged contact — body fluids or other forms of close contact, such as sharing clothes or other materials that have been used by someone who is infectious.

“It’s a really rare illness, especially in high-resource countries like the U.S.,” Dr. Anthony Santella, an infectious diseases expert, said. “Even if it’s confirmed, it’s not like people who rode the subway or were at a public place need to panic.”