A 65-year-old man who crossed into the city from the mainland has been confirmed to have the potentially fatal H7N9 bird flu virus - taking the number of cases in Hong Kong to eight, all of them contracted across the border.
It comes just hours after Secretary for Food and Health Dr Ko Wing-man said that an H7N9 vaccine developed in Hong Kong may be available to high-risk groups before the year is out.
The man in the latest case fell ill in Shenzhen on Monday with a fever and diarrhoea and was coughing up blood. He arrived in Hong Kong via Lo Wu control point on Thursday and was taken by ambulance to the accident and emergency department of North District Hospital in Sheung Shui.
The man, who has underlying illnesses, lives alone in Shenzhen's Longgang district, but it was reported that he may originally be from Hong Kong. Last night he was in stable condition in isolation at Princess Margaret Hospital, Kwai Chung. He was said to have recently bought freshly slaughtered pigeons from a wet market near his home.
Hong Kong's Centre for Health Protection was notifying the World Health Organisation and its mainland counterparts.
A spokesman added: "In view of human cases of avian influenza A (H7N9) confirmed locally and on the mainland, further cases are expected, possibly in neighbouring areas. Those planning to travel outside Hong Kong should maintain good personal, environmental and food hygiene at all times."
Up to the end of February, there had been 375 confirmed cases of H7N9 across the mainland, Taiwan and Hong Kong. Some 115 cases proved fatal, including three in Hong Kong.
Earlier, Ko revealed the first jabs against the fatal strain were imminent. "The earliest chance that we could start using [the H7N9 vaccine] is late this year or early next year," he told the Legislative Council's Finance Committee in his report on health spending for this year - which he estimated at HK$52.4 billion.
He said the vaccine still had to undergo further tests. "But if successful, the application scope will be confined to high-risk groups only, like poultry trade workers and laboratory staff," he said.
The human vaccine against the H7N9 virus was developed in a joint project by the University of Hong Kong and the mainland's Zhejiang University, and the breakthrough was announced in October. HKU microbiologist Professor Yuen Kwok-yuen, who was involved in the research, said it showed China could create vaccines and "reach the stage of manufacturing in a very short period of time".