The monkeypox case was confirmed in a Massachusetts man who had recently traveled to Canada, state health officials said earlier in the day.
The patient is hospitalized in stable condition at Massachusetts General Hospital, Dr. Paul Biddinger, head of preparedness and continuity at Mass General Brigham, said during a press briefing.
The patient has been in an airborne infection isolation room since last Thursday.
“This patient, fortunately, is doing quite well now, although he had symptoms that required hospitalization,” said Dr. Erica Shenoy.
Biddinger said they don’t know how the patient became infected, but pointed out “historically it was a very rare disease, with very rare transmission around the world. What we’ve seen at UK, Spain and Europe has been new and it worries us, but I rightly think people shouldn’t be afraid of monkeypox at this time.”
He said the current patient posed “no public health risk”, adding that people should “be aware of the symptoms but not be afraid”.
Shenoy, medical director of the Region 1 Emerging and Special Pathogens Treatment Center, said the patient had the West African strain of monkeypox, which is known to be less severe.
Health officials are conducting contact tracing for the patient, Shenoy added.
Testing of the individual was first performed at the state public health laboratory on Tuesday, and on Wednesday the CDC confirmed the case through its own testing.
Canadian health authorities said no cases of monkeypox have been reported to the Public Health Agency of Canada.
Multiple clusters reported across the world
“It is unknown how individuals in these groups were exposed to monkeypox, but the cases include individuals who identify as men who have sex with men,” the agency said in a press release.
“Many of these global case reports of monkeypox occur within sexual networks. However, healthcare providers should be alert to any rash with typical features of monkeypox. We ask the public to contact their healthcare provider if they have a new rash and are concerned about monkeypox,” Dr. Inger Damon, director of the CDC’s Division of Pathogens and High Consequence Conditions, said in the press release.
The CDC says people who may be showing symptoms of monkeypox and those in close contact with them should contact their doctor if they experience any unusual rashes or lesions. Symptoms may include a flu-like illness, swollen lymph nodes, and a rash on the face and body.
Monkeypox is a rare but dangerous infection similar to the now eradicated smallpox virus. It is usually contracted by a rodent or small mammal and is not easily transmitted from person to person. However, monkeypox virus can be spread through contact with body fluids, monkeypox sores, or items such as clothing and bedding that have been contaminated with the virus. It can also spread from person to person through respiratory droplets, usually in a close environment, according to the CDC.
The Massachusetts case is the first reported case this year. The first known case of monkeypox associated with travel to the United States involved a man traveling from Nigeria to Texas in July 2021. A second US case was identified later that year, also involving a traveler from Nigeria.
CNN Health’s Michael Nedelman and John Bonifield contributed to this report.