The Centre for Health Protection said on Wednesday night that the man, 37, was admitted to Tsuen Wan’s Yan Chai Hospital with a fever and decreased conscious level on March 21.
It added that a test of his cerebrospinal fluid came back positive for the B virus, also known as the human simiae virus.
The man was currently in a critical condition and receiving treatment in the hospital’s intensive care unit, it said.
The centre said a preliminary investigation indicated the patient previously had contact with wild monkeys and was injured during a trip to Kam Shan Country Park in late February.
Macaques, a type of wild monkey common in Hong Kong, naturally carry the virus in their saliva, urine and stool.
Humans can contract the virus from monkey bites or scratches, which can trigger flu-like symptoms that can develop into a potentially fatal central nervous system infection.
The centre noted that human-to-human transmission was extremely rare.
While this was Hong Kong’s first recorded case of a person contracting the virus, other instances had occurred in the United States, Canada, mainland China and Japan, it said.
The first documented case of a human becoming infected with the B virus was in 1932.
While cases involving people are rare, the mortality rate is more than 70 per cent without antiviral therapy, according to the US Centre for Disease Control and Prevention.
5 Hong Kong hikers rescued with help of police SOS mobile phone app in 2 months
5 Hong Kong hikers rescued with help of police SOS mobile phone app in 2 months
Three years ago, a Beijing-based veterinarian became the mainland’s first confirmed case. The Chinese Center for Disease Control and Prevention later confirmed the patient had died from the condition.
Hong Kong health authorities have urged the public to avoid interacting with any wild monkeys and to ensure any bites or scratches were washed immediately to reduce the risk of transmission.
The centre on Wednesday said epidemiological investigations into the city’s first recorded case were ongoing.
