FILE - The arms and legs of a 4-year-old girl infected with monkeypox. (BSIP/UIG Via Getty Images)
REDWOOD CITY, Calif. - The first case of a new strain of mpox in the United States has been reported in San Mateo County, officials said Saturday.
California's Department of Public Health reported the case to the Centers for Disease Control and Prevention, who say it is the first reported case of mpox in the country after the patient recently traveled outside the U.S.
According to the CDPH, the patient recently returned traveling from Africa, and their diagnosis is related to the ongoing outbreak in Central and Eastern Africa.
Mpox, formerly known as monkeypox, is a rare disease caused by infection with a virus that’s in the same family as the one that causes smallpox.
Milder symptoms can include fever, chills and body aches. In more serious cases, people can develop lesions on the face, hands, chest and genitals.
The strain reported in San Mateo County is clade I, different from clade II which has been reported in the US and California since 2022.
The new strain historically has caused more severe illness, however, recent infections from clade I may not be as clinically severe as it had been previously, especially when cases have access to quality medical care, according to the CDPH.
To date, there have been 108 confirmed cases of the clade II strain of mpox in San Mateo County, according to the San Mateo County Health Department.
The patient diagnosed with the new strain is isolating at home and recovering.
"While clade I may be new to the United States, we and other counties have been responding to mpox since 2022 with contact tracing, guidance and vaccine support," San Mateo County Health Officer Dr. Kismet Baldwin-Santana said. "Given the very low risk to the public of exposure to clade I, the standing guidance for preventing mpox has not changed."
Those with close contact with the patient are being contacted by public health workers, though officials said there's no evidence the new strain is spreading and that the exposure to the public remains very low.
Officials said to help prevent mpox, those at risk should get vaccinated, avoid skin-to-skin contact with those with a rash or sores that look like mpox, don't share items to those with the disease, wash your hands often, and use PPE whenever possible around those with mpox.
Dr. Peter Chin-Hong in San Francisco, said he is not concerned about the general population.
"It's still hard to get mpox. Even when someone has it, with the right control, it's going to be hard for others to get it," Chin-Hong said.
Specimens from the patient have been sent to the CDC for testing, officials said.
Scientists reported the new strain in Africa that was spreading through close contact, including through sex.
The CDC said the spread outside Africa has been very limited. Over 3,100 cases have been confirmed according to the World Health Organization, with most of them concentrated in Burundi, Uganda, and the Democratic Republic of the Congo.
The new strain has also been seen in Germany, India, Kenya, Sweden, Thailand, Zimbabwe, and the United Kingdom.
Fox TV Digital Team contributed to this report.