Hong Kong’s dengue fever outbreak shows mosquito control must start earlier in the year
I see from your reports that the Lion Rock Park has been identified as a suspected source of this year’s outbreak of dengue fever. After reports of the first few cases, Food and Environmental Hygiene Department and other government workers moved into the park to kill the virus carrier , the Aedes albopictus mosquito. Now, the park has been shut for 30 days , but it is more than likely that some of the mosquitoes will have travelled further afield.
It seems that every year the infestation, whether of the Aedes mosquito or more common species, has to have started before action is taken. Preventive measures can be and should have been taken much earlier – no later than June.
As well as a few empty tin cans that might have been left behind by picnickers and served as breeding grounds for mosquitoes, there are a few mountain creeks that burst their banks after heavy downpours and leave behind puddles of stagnant water on the banks for long enough to create many more such breeding grounds.
These creeks are difficult to access on foot to administer the insecticides. But the same government helicopters that make the loudhailer announcements of hill fire hazard warnings could be used to fumigate these creeks from about early May , and not wait until anti-mosquito pamphlets are distributed later in the summer. The mosquito eggs that survived the winter would then have been wiped out.
Peter Lok, Heng Fa Chuen