THOSE living in Malaysia would be accustomed to its searing heat and torrential rain.
But few realise that this alternating weather pattern creates the perfect breeding conditions for the vector of dengue — Aedes mosquitoes.
hile it was reported that dengue cases dropped during the previous two movement control order (MCO), the public should not get complacent as the months of May and June are when incidences typically surge.
The warning came from UOW Malaysia KDU Penang University College Pre-University Studies lecturer and department head Dr Ong Song Quan, who is also an entomologist and professional chemist.
Dr Ong pointed to the simulated model for 2020 (which did not take into account the implementation of MCO 1.0) which showed a downward trend of cases at the beginning, followed by a significant spike in the middle of the year.
“If the same model were to be applied to 2021, a surge is expected this month and next.
“The ‘U’ trend in dengue incidences and the low levels of dengue reported last year could be due to several factors.
“The period between March and May typically sees a decline in reported dengue cases. But meanwhile in the background, Aedes mosquitoes are quietly breeding as it is the transition of the northeast monsoon season, which present ideal breeding conditions.
“So in May and June, there is usually an increase. However in 2020, this was somewhat inhibited by movement restrictions that resulted in people staying at home and being more attentive about their living environments.
“This significantly curtailed opportunities for mosquitoes to find suitable breeding spots.
“In addition, there are indications that dengue-infected patients may also have been afraid to seek treatment due to their concern of contracting Covid-19.
“Finally, there is also the possibility that in the middle of the pandemic, dengue incidences may have been under-reported due to the overwhelming number of Covid-19 cases putting a strain on the healthcare system, ” Dr Ong shared with The Star.
And although there is currently a nationwide lockdown until early June, people have more freedom of movement compared to last year. Which could result in a spike of dengue cases if people do not take pre-emptive measures to protect themselves.
“Just as we’ve become accustomed to being part of the public health solution to keep Covid-19 in check, now is also the time for us to mobilise and take action against the Aedes mosquito.
“The ultimate solution is to reduce potential breeding sites by identifying and eliminating them, as advocated in the Ministry of Health’s 10-minute Hapuskan Aedes campaign, ” Dr Ong urged.
In this regard, he said household insecticides and repellents can be helpful when complete cleaning of one’s housing or living area is not possible.
However, one needs to have a basic understanding of the formulation, and weigh up each option’s convenience of use, price and duration of protection, to maximise efficiency and ensure personal safety.
Dr Ong said aerosol sprays are convenient and have a good knock-down effect, but come with some hazards.
Inhalation of droplets can lead to adverse health impacts, while the can itself can be dangerous if punctured, overheated or used near an open flame.
He continues: “Mosquito coils are also a popular choice locally, providing up to eight-hours of protection.
“The downside is that it generates smoke that may lead to respiratory health complications. However, there are some smokeless products now.
“Mosquito mats are cardboard mats infused with insecticidal solutions. These are clean and smokeless, but have inconsistent performance.
“Electric liquid vaporisers meanwhile offer protection up to 90 hours.
“The drawback is that the heater needs to be switched on two hours prior to bedtime and requires brand-specific replaceable refills. This can be expensive.
“Repellents that are applied to the skin, clothing or surfaces can offer personal protection especially in outdoor environments.
“But duration may be an issue as these wear off over time.”