No evidence of transmission chain after HK’s first local chikungunya case, says health chief

Health authorities have launched extensive contact tracing and mosquito control operations in Diamond Hill after recording the first local infection of chikungunya fever, though officials stressed there is currently no evidence of a transmission chain in the city.

The comments came after Hong Kong has recorded its first locally acquired case of chikungunya fever, with an 82-year-old woman from Suet Fung House of Fung Tak Estate in Diamond Hill testing positive for the mosquito-borne disease.

Speaking on a radio program on Monday morning, Edwin Tsui Lok-kin, Controller of the Centre for Health Protection (CHP), said the patient had no recent travel history but is believed to have contracted the virus locally after another infected individual likely brought it into Hong Kong.

“Epidemiological investigations show no connection with previously recorded cases,” Tsui said. “We believe someone infected overseas may have entered the city without seeking medical attention, allowing local mosquitoes to spread the virus.”

Tsui emphasised that while the case is Hong Kong’s first home-grown infection, it remains premature to conclude that a full transmission chain has formed in the district.

“The risk mainly comes from mosquitoes carrying the virus,” he explained. “As long as infected mosquitoes with transmission potential exist within the estate, there will be some level of risk.”

Active tracing and mosquito control underway

Health officers have begun active case finding in the surrounding community and are urging residents citywide to remain vigilant. Tsui said no other suspected infections have been identified so far, but warned that “no reported cases do not mean zero risk.”

He called on the public to take preventive measures by eliminating stagnant water and improving environmental hygiene to curb mosquito breeding.

Tsui added that Hong Kong has strengthened its anti-mosquito operations since mid-year, following reports of imported cases.

“The mosquito vector index in the Diamond Hill area is not high. From a data perspective, the situation is manageable,” he said. “Still, even a small number of infected mosquitoes can pose a risk, so we must continue to suppress the adult mosquito population to the lowest possible level.”

Nearby school steps up inspections

Within a 200-metre radius of Suet Fung House sits AOG St. Hilary's College’s primary and kindergarten sections, where principal Chu Tsz-wing said precautionary measures were immediately rolled out after receiving notice from the CHP.

“Although a four-lane road separates our campus from the estate, we acted at once,” Chu said on the same radio program. “Our school is mostly indoors, without gardens or planters, so the mosquito problem is relatively mild.”

He said staff have been deployed to inspect the campus for stagnant water and to educate students and teachers on chikungunya prevention, while awaiting further guidance from the CHP and other departments.

Residents within 200-meter radius on alert

According to Tsui, residents living within roughly 200 meters of the patient’s building — an area encompassing about 20 residential blocks — face potential exposure risks.

Authorities began contacting affected households on Sunday to remind them to monitor their health and report any symptoms such as fever, joint pain, or rashes.