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Patient tests negative for dengue fever

     The Centre for Health Protection (CHP) of the Department of Health (DH) today (July 24) provided an update on a suspected local case of dengue fever (DF) on July 16 affecting a woman aged 47. Further laboratory testing indicated that she did not have dengue virus infection.

     Her latest blood sample tested negative yesterday (July 23) for antibodies to dengue virus by the CHP's Public Health Laboratory Services Branch.

     Meanwhile, an additional confirmed case was recorded from July 16 to 23 affecting a patient who travelled to Laos, Vietnam and Cambodia during the incubation period.

     As of July 23, a total of 53 cases had been confirmed this year, comprising a local case and 52 imported cases.

     "The number of cases recorded so far in 2015 is the highest compared with those of the corresponding period in the past 10 years (figures ranged from nine to 46 cases from 2005 to 2014). The number of cases is expected to increase as more people will travel during the summer vacation.

     "Dengue viruses encompass four different serotypes. The symptoms of first infection with one serotype are usually mild, but subsequent infections with other serotypes even years afterward are more likely to result in severe dengue (also known as dengue haemorrhagic fever). Severe dengue is serious and potentially fatal. Without proper treatment, the case fatality rate of severe dengue can exceed 20 per cent," a spokesman for the CHP said.

     "According to the World Health Organization, although clinical trials on humans for some dengue vaccine candidates are ongoing, none are now available and registered with any drug regulatory authorities. Strict environmental hygiene, mosquito control and personal protective measures hence remain the most effective means against DF both locally and during travel," the spokesman added.

Avoid mosquito bites

     Travellers should stay alert to the DF risk before departing, and take heed of the preventive measures below:

* Wear loose, light-coloured, long-sleeved tops and trousers, and use DEET-containing insect repellent on exposed parts of the body and clothing;
* Avoid using fragrant cosmetics or skin care products and re-apply insect repellents according to instructions in outdoor activities;
* Before the trip, arrange travel health consultation at least six weeks in advance for any extra measures against mosquito bites; and
* During the trip, carry a portable bed net and apply permethrin (an insecticide) on it in rural endemic areas. Permethrin should not be applied to skin.
     The incubation period of DF ranges from three to 14 days, commonly four to seven days. Anyone feeling unwell after returning from a trip should seek medical advice as soon as possible and provide travel details to their doctors.

Remove breeding sites
     Members of the public should also prevent the accumulation of stagnant water and maintain good environmental hygiene:
* Change the water in vases once a week;
* Clear the water in saucers under potted plants every week;
* Cover water containers tightly;
* Ensure air-conditioner drip trays are free of stagnant water;
* Put all used cans and bottles into covered dustbins; and
* Store food and dispose of garbage properly.

     Members of the public are reminded to make reports to government departments via the hotline 1823 if mosquito problems are detected, and may visit the pages below for more information:

* The CHP's DF page (;
* The DF page of the DH's Travel Health Service (;
* The DH's latest Travel Health News (;
* The CHP's tips for using insect repellents (;
* The CHP Facebook Page (;
* The CHP YouTube Channel (; and
* The FEHD's Guidebook on Control and Prevention of Mosquito Breeding (

Ends/Friday, July 24, 2015
Issued at HKT 15:17


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