Hong Kong health authorities are investigating a new monkeypox case involving a 34-year-old man who is a close contact of the city’s fifth confirmed infection.

The Centre for Health Protection said the man was epidemiologically linked to the other patient, 59, who was confirmed to have contracted the rare disease caused by the monkeypox virus last Friday.

The latest patient was in good health before becoming infected, the centre said. He was admitted to Alice Ho Miu Ling Nethersole Hospital in Tai Po for precautionary quarantine on Sunday, when he also developed a rash on his body.

The centre’s public health laboratory services branch confirmed the man tested positive for the virus on Monday. He was in a stable condition.

The man, who had not been vaccinated against the disease, had been in Taiwan from April 9 to 15.

Two of his household members would be quarantined and given post-exposure vaccinations, the centre said, adding that they remained asymptomatic.

Epidemiological investigations were ongoing.

The centre said it would report the case to the World Health Organization.

The 59-year-old man’s case was the city’s fifth confirmed monkeypox infection. The man has a chronic illness and was admitted to Princess Margaret Hospital in Kwai Chung. He was reported as being in a stable condition.

Investigation found the patient, who had travelled to mainland China’s Guangdong province multiple times from April 2 to 19, had high-risk exposure during the incubation period.

Hong Kong’s third, fourth and fifth cases were all recorded last month. One instance involved a man, 25, who had visited South Korea and Japan while the other infected patient, 34, was his close contact who was earlier confirmed to have the virus.

The city had its first confirmed case of the virus last September when a man, 30, returned from visiting the Philippines.

Monkeypox is a viral disease that spreads through prolonged contact between people. It causes a distinctive bumpy rash, fever and muscle aches. The most recent outbreak has spread to more than 100 countries.

Authorities urged the public to be more vigilant, avoid close physical contact with people suspected of having monkeypox, and to get vaccinated if they are considered part of a high-risk target group.