New mosquito trap from Netherlands will combat rise of dengue fever in Hong Kong and target insect at all stages of its life cycle
- New device is being tested by the Food and Environmental Hygiene Department
- Comes after city reported a surge in local dengue fever cases last year
A new mosquito trap targeting larvae and the adult insects is to be introduced by the environmental hygiene authorities to help curb the growth of the pest in Hong Kong.
The new device, which is from the Netherlands and is being tested by the Food and Environmental Hygiene Department, arrived as concerns over mosquito control work grew after the city reported a surge in local dengue fever cases last year.
The outbreak of the mosquito-borne disease prompted the closure of Lion Rock Park for nearly two months to prevent further transmission of cases.
Lee Ming-wai, the department’s pest control officer-in-charge, said the latest device could target mosquitoes at different stages of their life cycle.
“The new mosquito trap could achieve two functions – controlling larvae and adult mosquitoes at the same time,” Lee said.
The approach is in contrast to conventional wisdom, which relies on the use of separate methods. While control of adult mosquitoes is done with ways such as fogging, measures for larvae included application of larvicidal oils in stagnant water.
The black-coloured device, which includes a small plastic bucket and a lid, kills mosquitoes mainly with a powder that contains a type of pesticide and a fungus. It aims to lure female mosquitoes to lay eggs in the bucket of water containing the powder.
At the same time, those mosquitoes also pick up the powder after coming into contact with a specially treated gauze inside the bucket.
The pesticide, pyriproxyfen, stops larvae from developing into adult mosquitoes. The fungus also kill mosquitoes within a few days.
This device particularly targets Aedes mosquitoes, which transmit diseases such as dengue fever and the Zika virus.
“Aedes mosquitoes usually do not lay all their eggs in the same body of water,” Lee said. “When they move to another pool of stagnant water to lay eggs, those that have previously picked up the pesticide would spread it to the water body, meaning eggs laid there can’t be developed into adult mosquitoes.”
The department is going to test how effective the device is before using it more extensively across the city. Two to three remote places that are favourable for mosquito breeding will be chosen for a trial for two to three months.
“This device would be a supplementary tool,” Lee said. “If mosquito control outcome was not satisfactory in places where conventional methods have been used, we would place these mosquito traps there and hope to achieve a better effect.”
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The risk of dengue fever spreading locally continued to be a concern this year, Lee added, as the disease remains an epidemic in many Southeast Asian countries and the city reported 29 local cases in 2018.
That number was unusually high given only one local case was recorded in 2017, and four in 2016.
A citywide anti-mosquito operation was also kicked off by authorities on Monday.
Peter Leung Kwong-yuen, president of the Pest Control Personnel Association of Hong Kong, said authorities should take note of locations when placing the new trap.
“The location of those devices should be out of human intervention,” Leung said. “If places nearby the device were spread with pesticide, mosquitoes would not be attracted to the device.”
He said the government had been more vigilant in mosquito control work this year, but he called for an improvement in the technical standards of frontline workers.
