The Philippines reported its first case this year of mpox, previously known as monkeypox, on Monday, just days after the World Health Organization declared the disease a global health emergency.

The Philippines Department of Health, in a statement announcing the case, did not say whether the patient was infected with Clade Ib, the newer and potentially more deadly version of the mpox virus that is dominant now in the Democratic Republic of Congo, driving a rise in cases there.

It was an older strain, Clade IIb, that caused a worldwide outbreak of mpox in 2022.

Last Thursday — a day after the W.H.O. declaration of a global emergency — officials in Sweden revealed that a patient there was the first person outside of Africa to be diagnosed with the new strain, setting off fears of a much wider spread. Also on Thursday, Pakistan announced a case of mpox but said it was not yet clear which strain of the disease was involved.

Here is what we know.

The case in the Philippines

The patient is a 33-year-old Filipino man with no travel history outside of the country, whose mpox infection was confirmed and reported on Sunday to the Department of Health, the department said.

The man became sick more than a week ago, first with a fever, “followed four days later by findings of a distinct rash on the face, back, nape, trunk, groin, as well as palms and soles,” the department said. The patient was seen in a government hospital, where samples of his skin lesions were taken to test for genetic evidence of the virus.

The Philippines’ secretary of health, Dr. Teodoro J. Herbosa, discouraged public panic by emphasizing that officials were working to make testing convenient. “Our health system is working,” he said in a statement, “we can handle the situation and will keep the public well-informed.”

The latest case is only the 10th ever confirmed infection with mpox in the country, and all previous cases were isolated and patients have since recovered, the department said.

Mpox and its spread

Mpox is a virus endemic to Central and Western Africa. It is similar to smallpox but less contagious, and spreads primarily through close contact with infected animals or people, or the consumption of contaminated meat. It can also be spread through sexual contact or transmitted in utero to a fetus.

The disease’s rapid spread in 2022 led the World Health Organization to declare the mpox epidemic a global health emergency in July of that year, and infections were detected in over 70 countries that had never previously reported the disease. Since then, it has affected nearly 100,000 people in 116 countries.

The outbreak has largely subsided in Europe, Asia and the Americas, but it has not been eradicated — there have been hundreds of cases in the United States this year. At the same time, it has worsened in parts of Africa this year, leading the W.H.O. to declare once again that mpox is a global health emergency.

Smallpox vaccination, which was nearly universal half a century ago, gives a high degree of resistance to mpox infection. But smallpox was declared eradicated in 1980, and since then few people have received the vaccine.

Fever, headache, muscle aches and a blistering rash that progresses to pustules, which eventually scab over, are common signs of the disease. Symptoms can last two to four weeks, and treatment relies heavily on supportive care and alleviating symptoms.

How is this outbreak different?

The 2022 outbreak was primarily a version of mpox spread through sexual contact, and men who had sex with men were deemed most at risk. The spread was curbed through a combination of vaccinations and behavioral change, though health agencies like the W.H.O. and the U.S. Centers for Disease Control and Prevention have reported that new infections were still occurring this year.

In 2022 and 2023, there was a push to inoculate people who were at risk, particularly men who had sex with men, but the C.D.C. reported that most people in that group were not vaccinated.

The newer mpox strain that has been spreading in Congo has a death rate of 3 percent, much higher than the 0.2 percent death rate observed in the 2022 outbreak, and the populations most at risk appear to be different.

Women and children are most affected this time, according to Save the Children, an international charity, and doctors have reported treating entire families.