Thai health officials are reporting the suspected first case of the new, more dangerous strain of mpox in the country, in a European traveler who arrived in Thailand from Africa last week.

In a statement on its website Thursday, Thailand’s Department of Disease Control reported that a 66-year-old man who arrived in the country on August 14 was hospitalized with symptoms the following day and has since been quarantined. They said his symptoms are not severe.

Testing showed the man did not have the clade 2 variant, the previous strain of the virus, but tests for the new, more dangerous clade 1b strain were inconclusive.

At a news conference in Bangkok, Department of Disease Control chief Thongchai Keeratihattayakorn told reporters they expect to have results of additional testing by Friday.

“We are convinced the person has the clade 1b variant,” Thongchai told French news agency Agence France-Presse.

Last week, the World Health Organization declared the new mpox variant outbreak a public health emergency of international concern after a surge in cases in the Democratic Republic of Congo and outbreaks in other central African nations, including Burundi, Uganda, Rwanda and Kenya.

In Thailand, the Department of Disease Control said it is monitoring 43 people who had close contact with the patient before he traveled to Thailand. Thonchai said that although the people currently have no symptoms, they will be monitored for 21 days from August 14 — the day they came in contact with the patient.

Mpox, formerly known as monkey pox, is a viral infection with symptoms that can include rash or lesions, fever, muscle aches and swollen lymph glands. Most patients fully recover, but some get very sick and die. It is most commonly transmitted through close, physical contact with someone who is infectious.

The new clade 1b variant is believed to be transmitted more easily. WHO said there are two recommended vaccines in use to prevent mpox, and it has triggered the process for emergency use listing for mpox vaccines, which will accelerate vaccine access for lower-income countries.

Some information for this report was provided by Reuters and Agence France-Presse.