Hong Kong’s fourth locally reported case of chikungunya fever could have resulted from a new source of infection unrelated to previous ones, a leading medical expert has warned, adding that heightened surveillance by authorities could uncover more patients.

Professor Jasper Chan Fuk-woo of the University of Hong Kong’s microbiology department issued the warning on Friday, a day after a 68-year-old woman living in Shau Kei Wan was listed as the city’s fourth locally acquired case.

“Based on the epidemiological investigation findings released so far, this new case likely represents a new source of infection not linked to the previous three local cases,” he told the Post.

“Genomic analysis of the virus strain should provide further information on this,” he said, adding that such a discovery raised concerns of undetected ongoing transmission chains.

The latest patient developed joint pain on Monday and sought help at Pamela Youde Nethersole Eastern Hospital in Chai Wan after suffering from a fever and rash the next day.

Health authorities said she had no travel history for the past two months, adding that her residence and usual activity areas did not overlap with neighbourhoods where existing cases had been found in recent months.