LETTERS: A weather pattern of intermittent sun with rain in Malaysia creates the perfect breeding conditions for the vector of dengue — the Aedes mosquito.
Dengue cases dropped during the Movement Control Order (MCO) 2.0. However, we should not be complacent as they are set to surge this year from May to June.
According to a model simulation study in 2020, which did not expect the implementation of the MCO 1.0, it was found that the actual trend in dengue cases was lower in the beginning, but later it demonstrated a significant spike in transmission.
If the same forecast model is used now, the trend for dengue cases might show a surge later from now to next month. Aedes mosquitoes are now quietly breeding and we could face a dengue spike in two months.
Between March and May, we typically see a decline in reported dengue cases, but Aedes mosquitoes are quietly breeding as it is the transition of the Northeast monsoon season.
In May and June, we typically see an increase. However, last year, this was inhibited by the MCO, which resulted in less movement of people and greater attentiveness to home environments, hence reducing breeding spots for mosquitoes.
Also, dengue-infected patients might be afraid to visit hospitals for treatment due to concern about contracting Covid-19. Finally, there could have been under reporting of dengue incidences due to the overwhelming number of Covid-19 cases.
So what can we do to protect ourselves in the coming weeks?
The ultimate solution is to reduce potential breeding sites as in the Health Ministry's "10-minit Hapuskan Aedes" campaign to eliminate potential breeding places.
In this regard, household insecticides can be helpful.
Below are the pros and cons of household insecticides in the market.
AEROSOLS
A self-contained system that emits space-spray droplets of insecticides into the air. Pros: Convenient to use. Usually consists of active ingredients that bring knock-down and repellent effect. Cons: Failure to comply with the instructions on its application might lead to inhalation injury.
MOSQUITO COIL
A formulation of insecticides, wood powder, dye and other additives. Pros: Easy to use. Provides continuous protection for eight hours with consistent performance. Cons: Generates smoke that might lead to respiratory health complications (although some products contain "smokeless"
formulation).
MOSQUITO MAT
A cardboard mat that is infused with insecticide solution. Pros: Clean (smokeless). Cons: Inconsistent
performance.
ELECTRIC LIQUID VAPORISER
Consists of an electrical heater with a reservoir of liquid insecticides. Pros: Clean. Provides protection that lasts for 30, 60 and 90 hours. Cons: The heater needs to be switched on two hours prior to bedtime and requires brand-specific replaceable reservoir. More expensive.
REPELLENT
Chemicals applied to the skin, clothing, or other surfaces. Pros: Provide personal protection, especially outdoors. Cons: Duration might be an issue. At the moment, DEET is still the most effective repellent.
The selection of a suitable insecticide formulation depends on several factors, such as the convenience of use, particular conditions surrounding the treatment, price and duration of protection.
A basic understanding of formulation before purchasing the insecticides helps us to avoid mistakes in using the product and most importantly protects us and our family from dengue.
Just as Malaysians have become accustomed to being part of the public health solution for Covid-19, now is the time for us to identify potential mosquito-breeding grounds and take action.
DR ONG SONG QUAN
Lecturer, Head of Department
University of Wollongong (UOW) Malaysia, KDU
The views expressed in this article are the author's own and do not necessarily reflect those of the New Straits Times