"The patient is an adult resident who recently traveled and had a known close contact to a case,'' according to a statement from the county Department of Public Health. "Although the patient is symptomatic, they are doing well and not hospitalized. They are isolated from others.''
Health officials said contact-tracing is being performed to identify anyone who was in close proximity to the patient, and "post-exposure prevention'' efforts have been enacted for close contacts.
Last week, the World Health Organization said 23 countries that haven't previously had monkeypox have now reported more than 250 cases. On Monday, the U.K. announced another 71 monkeypox cases.
What is monkeypox? What to know about virus, symptoms, spread
Monkeypox is known to spread when there is close physical contact with an infected person, their clothing or bedsheets.
Most monkeypox patients experience only fever, body aches, chills and fatigue. People with more serious illness may develop a rash and lesions on the face and hands that can spread to other parts of the body. No deaths have been reported in the current outbreak beyond Africa.
Monkeypox is related to smallpox, but has milder symptoms. After smallpox was declared eradicated in 1980, countries suspended their mass immunization programs, a move that some experts believe may be helping monkeypox spread now, since there is now little widespread immunity to related diseases. Smallpox vaccines are also protective against monkeypox.
Answers to frequently asked questions about monkeypox are available on the Department of Public Health's website.
The Associated Press contributed to this report.