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Remove stagnant water after rain to prevent dengue fever and Zika Virus Infection
     The Centre for Health Protection (CHP) of the Department of Health today (May 26) again urged the public to prevent the accumulation of stagnant water amid the rainy season to guard against mosquito-borne diseases including dengue fever (DF) and Zika Virus Infection.

     "After a rainstorm and flooding, it is very important to quickly remove stagnant water in outdoor and household settings to stop mosquitoes from breeding. As a regular habit, the public should change the water in vases once a week, clear the water in saucers under potted plants every week, and ensure air-conditioner drip trays are free of stagnant water," a spokesman for the CHP said.

A. Dengue fever

     From May 19 to 25, the CHP recorded two confirmed cases and both patients had been to Thailand in the incubation period. As of yesterday (May 25), among the 31 cases in 2017, about one-third (10) were imported from Thailand, followed by the Philippines (five), Indonesia and Sri Lanka (four each). No local cases have been recorded so far.

     Dengue remains endemic in some areas in Asia. In 2017, 11 062 cases were recorded in Thailand, 1 067 in Singapore and 67 in Japan since January 2.

     Locally, the monthly ovitrap index (OI) for Aedes albopictus increased from 0.1 per cent in March to 1.8 per cent in April. While the survey in May is in progress, indices of some areas have already exceeded 20 per cent and reached Level 3 out of four, i.e. infestation exceeded one-fifth of the area surveyed. Members of the public in these areas, especially residents and workers, should check their household or workplace for potential mosquito breeding sites and remove them, and leave no stagnant water.

B. Zika Virus Infection

     The CHP noted that the World Health Organization (WHO) had reclassified India under Category 2 out of four which is considered to have ongoing Zika virus transmission (affected area). The WHO's classification of Zika-affected areas has been uploaded to the CHP's webpage for easy reference.

     "The public should continue to pay attention to these areas and observe our ongoing health advice and special notes during travel. Pregnant women and those planning pregnancy should not travel to affected areas," the spokesman said.

     To reduce the risk of infections spread by mosquitoes, apart from general measures, travellers returning from affected areas should apply insect repellent for 14 days (DF) or at least 21 days (Zika Virus Infection) upon arrival in Hong Kong. If feeling unwell, seek medical advice promptly and provide travel details to the doctor. DEET-containing insect repellents are effective and the public should take heed of the tips below:
  • Read carefully the label instructions first;
  • Apply right before entering an area with risk of mosquito bites;
  • Apply on exposed skin and clothing;
  • Use DEET of up to 30 per cent for pregnant women and up to 10 per cent for children;
  • Apply sunscreen first, then insect repellent; and
  • Re-apply only when needed and follow the instructions.

     The public may refer to the CHP's tips for using insect repellents for details.
Ends/Friday, May 26, 2017
Issued at HKT 16:48
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