1st monkeypox case in US this year reported in Massachusetts

A Massachusetts resident has tested positive for monkeypox, health officials confirmed Wednesday, making it the first case of the rare virus detected in the United States this year.

According to a release from the Massachusetts Department of Public Health, the patient is an adult male who recently traveled to Canada. The department completed initial testing Tuesday and was confirmed by the Centers for Disease Control and Prevention.

"The case poses no risk to the public, and the individual is hospitalized and in good condition," MDPH stated in a press release. "DPH is working closely with the CDC, relevant local boards of health, and the patient’s health care providers to identify individuals who may have been in contact with the patient while he was infectious."

The New York City Department of Health announced Thursday that it was investigating a possible case of monkeypox. The patient is being cared for at Bellevue Hospital and all appropriate isolation measures are being followed, according to the department. The patient's tests will be sent to the CDC for confirmatory testing, the department said.

It comes after four more cases of monkeypox were identified in the U.K recently, bringing its nationwide total to nine since the beginning of May.

The resident was admitted to Massachusetts General Hospital in Boston on May 12 and "during the course of their admission they were identified as a possible monkeypox suspect," Dr. Erica Shenoy, associate chief of the hospital's infection control unit, told reporters during a briefing Wednesday.

Hearing about cases of monkeypox in the U.K. encouraged doctors to "think more broadly about the patient's diagnosis," Shenoy said.

Hospital officials said they are unaware of any cases in Canada at this time and do not know where the resident may have contracted the disease.

Monkeypox is a rare disease caused by the monkeypox virus. The first case among humans was recorded in the Democratic Republic of the Congo in 1970, and the illness has since spread to several other nations, mostly in central and western Africa.

It can transmit from animals to humans when an infected animal -- such as a rodent or a primate -- bites or scratches a person. The CDC said humans can also be infected when hunting wild animals or preparing bush meat for consumption.

The disease can also spread from person to person via large respiratory droplets in the air, but they cannot travel more than a few feet, so two people would need to have prolonged close contact.

The most common symptoms are fever, headache, fatigue and muscle aches.

Very few cases of monkeypox have been identified among Americans.

According to the CDC, the disease does not naturally occur in the U.S. Infections are usually identified among people who recently traveled to countries where monkeypox is more commonly found.

In 2003, 47 confirmed and probable cases were reported in six U.S. states, the first human cases reported outside of Africa.

All the infections occurred after coming into contact with pet prairie dogs, which in turn became infected "after being housed near imported small mammals from Ghana," the CDC stated.

Since then, just two other cases have been detected in the U.S., both associated with travel.

In July 2021, a case was confirmed in a Texas resident who had recently returned from Nigeria and in November 2021, another case was found in a Maryland resident who had also traveled to Nigeria.

ABC News' William Gretsky contributed to this report.