Health officials said Saturday they have confirmed the first U.S. case of a new form of mpox that was first seen earlier this year in eastern Congo.

The person had traveled to eastern Africa and was treated in San Mateo upon return, according to the California Department of Public Health . Symptoms in the individual are improving, and the risk to the public is low, the health department said. The individual was isolating at home, and health workers are reaching out to close contacts as a precaution, the agency said in a news release.

Mpox is a rare disease caused by infection with a virus that’s in the same family as the one that causes smallpox. It is endemic in parts of Africa, where people have been infected through bites from rodents or small animals. Milder symptoms can include fever, chills and body aches.

In more serious cases, people can develop lesions on the face, hands, chest and genitals. We'll send you the top local news stories every morning at 8 a.m.

By clicking subscribe, you agree to share your email address with Times of San Diego to receive our free newsletter and breaking news alerts. We won't use your email for any other purpose, and you can opt out at any time via an unsubscribe link. Earlier this year, scientists reported the emergence of a new form of mpox in Africa that was spread through close contact, including through sex.

It was widely transmitted in eastern and central Africa. But in cases that were identified in travelers outside of the contin.