Press Release

Update on number of dengue fever cases

30 April 2015

The Centre for Health Protection (CHP) of the Department of Health (DH) today (April 30) provided an update on the number of cases of dengue fever (DF) in Hong Kong, and again urged the public to maintain strict environmental hygiene, mosquito control and personal protective measures.

From April 24 to 29, six additional confirmed cases were recorded. The patients had travelled to Indonesia (two cases), Thailand (two cases), the Philippines (one case), and Thailand and Malaysia (one case), during the incubation period.

Among these six cases, epidemiological linkages were established among two patients who travelled together to Indonesia, and among two other patients who travelled together to Thailand.

As of April 29, a total of 30 cases were confirmed this year and all were imported. In 2014, there were three local and 108 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," 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.

The public may visit the pages below for more information:

• The CHP's DF page (This link will open in a new windowwww.chp.gov.hk/en/view_content/38847.html);
• The DF page of the DH's Travel Health Service (This link will open in a new windowwww.travelhealth.gov.hk/english/popup/popup_dengue.html);
• The DH's latest Travel Health News (This link will open in a new windowwww.travelhealth.gov.hk/english/outbreaknews/outbreaknews.html);
• The CHP's tips for using insect repellents (This link will open in a new windowwww.chp.gov.hk/en/view_content/38927.html);
• The CHP Facebook Page (This link will open in a new windowwww.fb.com/CentreforHealthProtection);
• The CHP YouTube Channel (This link will open in a new windowwww.youtube.com/c/ChpGovHkChannel); and
• The FEHD's Guidebook on Control and Prevention of Mosquito Breeding (This link will open in a new windowwww.fehd.gov.hk/english/safefood/handbook_prev_mos_breeding.html).