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The Centre for Health Protection (CHP) of the Department of Health (DH) is today (July 16) investigating a suspected local case of dengue fever (DF), and hence again urged the public to maintain strict environmental hygiene, mosquito control and personal protective measures both locally and during travel.
"The patient had no recent travel history and the infection might be locally acquired. While pending laboratory confirmation, as a precautionary measure, we are working closely with the Food and Environmental Hygiene Department (FEHD) to assess and prevent any possible spread," a spokesman for the CHP said.
The patient is a 47-year-old woman with good past health. She has presented with fever, headache, myalgia and mild joint pain since July 10. She attended the Accident and Emergency Department of North Lantau Hospital on the same day and was subsequently transferred to Princess Margaret Hospital for treatment. She was discharged on July 15.
As her blood sample tested positive for immunoglobulin M (IgM) antibodies to dengue virus but negative for dengue virus antigen and nucleic acid upon testing by the CHP's Public Health Laboratory Services Branch today, this case is now classified as a suspected case.
Initial enquiries revealed that the patient lived and worked in Lotus Pond Temple of Lantau Island. She recalled mosquito bites near the temple and mainly stayed around the temple during the incubation period. She had no travel history within the incubation period.
The patient's household contacts have remained asymptomatic so far and have been put under medical surveillance.
"Upon notification, the CHP immediately commenced epidemiological investigations and promptly informed the FEHD for vector investigation and mosquito control. The CHP's investigations and health education in the vicinity where the patient frequented are proceeding," the spokesman said.
To date, 52 DF cases have been confirmed this year including one local and 51 imported cases. In 2014, there were three local and 109 imported cases. In 2013, 103 cases were filed and all were imported.
Dengue viruses encompass four different serotypes. The symptoms of first infection with one are usually mild, but subsequent infections with the others are more likely to result in a serious complication, namely dengue haemorrhagic fever (DHF). DHF is a severe and potentially fatal complication. Without proper treatment, the DHF case fatality rate can exceed 20 per cent.
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.
Avoid mosquito bites
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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
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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.
The public may visit the pages below for more information:
* The CHP's DF page (www.chp.gov.hk/en/view_content/38847.html);
* The DF page of the DH's Travel Health Service (www.travelhealth.gov.hk/english/popup/popup_dengue.html);
* The DH's latest Travel Health News (www.travelhealth.gov.hk/english/outbreaknews/outbreaknews.html);
* The CHP's tips for using insect repellents (www.chp.gov.hk/en/view_content/38927.html);
* The CHP Facebook Page (www.fb.com/CentreforHealthProtection);
* The CHP YouTube Channel (www.youtube.com/c/ChpGovHkChannel); and
* The FEHD's Guidebook on Control and Prevention of Mosquito Breeding (www.fehd.gov.hk/english/safefood/handbook_prev_mos_breeding.html).
Ends/Thursday, July 16, 2015
Issued at HKT 22:08
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