A male patient, aged 45 with good past health, has developed high fever, chills, headache and dizziness since 29 July. He was sent to the Accident and Emergency Department (A&E) of Kwong Wah Hospital (KWH) and was admitted for management on the same day. Upon admission, he developed skin rash over his legs. He has all along been in stable condition and has been discharged today after symptoms subsided.

His blood sample tested positive for dengue virus upon laboratory testing. This is the first local case recorded this year. Excluding this case, as of 3 August, 59 imported cases had been recorded in 2017, including 18 from Thailand, ten from Sri Lanka and seven from the Philippines.

Epidemiological investigations of the Centre for Health Protection (CHP) of the Department of Health (DH) into the local case of dengue fever (DF) are ongoing. CHP officers have conducted questionnaire surveys in the vicinity of the residence of the patient concerned. Upon enquiries, none reported DF symptoms or required a blood test so far. No irregularities have also been detected so far. The CHP's medical surveillance is under way.

Patient had no travel history in the incubation period

Initial enquiries revealed that the patient lives in a unit on Cedar Street, Prince Edward, and works in the construction site of West Kowloon Station (WKS) of the Hong Kong Section of the Guangzhou-Shenzhen-Hong Kong Express Rail Link (XRL) near MTR Austin Station.

The patient had no travel history in the incubation period. He recalled frequent mosquito bites at his workplace and also some bites near his residence. His local movements before onset were mainly within his workplace and residence. His home contacts have remained asymptomatic and have been put under medical surveillance. Tracing of his workplace contacts is ongoing.

"We are working closely with the Food and Environmental Hygiene Department (FEHD) to assess and prevent any possible spread of infection. The FEHD's vector investigations, surveillance and control will follow. The Highways Department and MTR Corporation have also been informed for follow-up. Epidemiological investigations are ongoing," a spokesman for the CHP said.

Stepping up anti-mosquito measures

"The FEHD has been very concerned about mosquito infestation. Upon receipt of the DH's notification last night that the patient of the DF case lives in a unit on Cedar Street, Prince Edward, and works in the construction site of WKS of the Hong Kong Section of the Guangzhou-Shenzhen-Hong Kong XRL, we have today arranged staff to carry out inspections at the construction site and conduct entomological surveys in areas within a 500m radius of the construction site and his residence. The FEHD has also arranged pest control contractors to carry out mosquito prevention and control work at the above-mentioned areas, including clearing potential mosquito breeding grounds in the vicinity of Cedar Street, and conducting fogging operations, applying larvicides, and clearing stagnant water and disused articles in the outer area of the construction site of West Kowloon Station of the XRL and the vicinity of KWH. The FEHD has also collected samples of Aedes albopictus from the areas for virus testing, with a view to identifying the infection source of the DF case," said an FEHD spokesman.

"Furthermore, the FEHD has advised relevant government departments, construction sites and private housing estates within the areas to step up anti-mosquito measures in areas under their management, and provided them with technical advice to facilitate the implementation of effective mosquito prevention measures. The FEHD and the CHP have also held two health education talks today at the Henry G Leong Yaumatei Community Centre and the construction site of the XRL respectively for residents and construction site workers. To strengthen surveillance on the places the patient had visited, the surveillance period of the ovitraps for Aedes albopictus for Tsim Sha Tsui, Tsim Sha Tsui East, Mong Kok, Ho Man Tin and Sham Shui Po East in August and September will be extended from one week to two weeks per month."

In addition, the FEHD will step up inspections and take out prosecutions under the relevant ordinance against mosquito breeding. The FEHD set up four Pest Control Inspection Teams in May to step up inspections of construction sites and enforcement actions against mosquito breeding. In 2017 (as of 4 August), the FEHD has instituted 135 prosecutions for mosquito breeding found in relevant premises under the Public Health and Municipal Services Ordinance (Cap 132), comprising 127 cases involving construction sites and eight cases involving other premises. MIMS

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