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CHP investigates imported malaria cases
     The Centre for Health Protection (CHP) of the Department of Health (DH) is today (August 4) investigating a fatal imported malaria case. The CHP has also observed an upward trend in the number of imported malaria cases, which all involve persons coming from Africa. The public is urged to maintain strict environmental hygiene, mosquito control and personal protective measures both locally and during travel.

     From July 1 to August 4, the CHP recorded a total of 30 imported malaria cases involving 30 male patients aged 25 to 57 arriving in Hong Kong from July 1 to August 1, among which 21 of them arrived from Guinea, Africa. All patients underwent quarantine at designated quarantine hotels in accordance with relevant entry requirement upon arrival and a 52-year-old patient passed away during quarantine and post-mortem results revealed that he carried the malaria parasite. The remaining 29 have been sent to public hospitals for treatment and 10 of them have been discharged after treatment, while four and 15 of them are in serious and stable condition respectively (including four in Intensive Care Unit).

     The CHP is conducting epidemiological investigation and is following-up the travel collaterals of the cases who have been put under medical surveillance. Symptomatic patients will be sent to hospital while blood tests would be offered to those who are asymptomatic. Cases that test positive would be sent to hospital for treatment.

     Malaria is a communicable disease transmitted by an infected female Anopheline mosquito (malaria vector). When the mosquito bites a malaria patient, the mosquito becomes infected with Plasmodium and will pass on the Plasmodium when it bites another person. The Anopheline mosquito in Hong Kong include Anopheles minimus and Anopheles jeyporiensis. According to the malaria vector surveillance information of the Food and Environmental Hygiene Department, the two types of Anopheline mosquitos have not been found in urban areas in Hong Kong in recent years. Apart from the breeding of Anopheles jeyporiensis near Tai Lam Chung Reservoir in 2021, there have not been any spots with Anopheles minimus or Anopheles jeyporiensis breeding in the past 10 years. As such, the DH opined that the risk of local transmission of malaria is extremely low. Since imported malaria cases were found at quarantine hotels, the authority would follow-up on the mosquito infestation of relevant locations and step up anti-mosquito work on a needs basis. The last local malaria infection happened in 1998, and there were seven and four cases reported in Hong Kong in 2020 and 2021 respectively.

     "The public should remain vigilant as malaria is more common in some African and Southeast Asian regions. Travellers to malaria-endemic areas should use DEET-containing insect repellents both during travel and for 14 days after arrival back in Hong Kong," a spokesman for the CHP said.

     Malaria is a serious and sometimes fatal disease. Common symptoms of malaria include fever, chills, headache, muscle pain and weakness, cough, vomiting, diarrhoea and abdominal pain. Severe malaria is serious and potentially fatal without proper treatment.

     "There are effective drugs against malaria but early diagnosis and prompt treatment are crucial. The World Health Organization (WHO) advises travellers heading to malaria-endemic regions to use chemoprophylaxis and adopt anti-mosquito measures for prevention of infection. For vaccines against malaria, the WHO advises only children at malaria-endemic regions to receive vaccination but not adults. The vaccines are also not applicable for travellers going to these malaria-endemic regions. As such, strict environmental hygiene, mosquito control and personal protective measures remain the most effective means against malaria both locally and during travel," the spokesman added.

     Travellers are urged to be alert to the malaria risk of travel destinations before departing and to 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 repellent according to instructions during outdoor activities;     
  • Before the trip, arrange a travel health consultation at least six weeks in advance for any extra measures against mosquito bites;     
  • 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 the skin; and     
  • After returning from malaria endemic areas, continue to apply insect repellent for 14 days.

     The incubation period of malaria varies with different species of Plasmodium. This usually ranges from seven to 30 days but may be up to months or even longer after the bite of an infected Anopheline mosquito. Anyone feeling unwell after returning from a trip should seek medical advice as soon as possible and provide travel details to their doctor.

     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.

     â€‹Members of the public are reminded to make reports to government departments via the hotline 1823 if mosquito problems are detected, and may visit these pages for more information: the malaria page of the CHP, the latest Travel Health Newstips for using insect repellents, the CHP Facebook Page and YouTube Channel, and the Food and Environmental Hygiene Department's Guidebook on Control and Prevention of Mosquito Breeding.
Ends/Thursday, August 4, 2022
Issued at HKT 20:35
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