In the first three weeks ( epidemiological weeks ) of 2023 alone , there were a massive 7,058 cases , an increase of 226 per cent compared to 2,165 cases reported during the same period in 2022 .

There was a total of three deaths due to dengue ( case fatality rate ( CFR ) 0.04 per cent ), compared to zero deaths during the same period in 2022 ( CFR zero per cent ).

So , while Malaysia is finally recovering from the Covid-19 pandemic , the dengue threat remains a major public health hazard . Based on national data , the dengue trend follows a cyclical pattern , with an epidemic reported every four to five years .

The two recent dengue epidemics were observed in 2015 and 2019 , with an average of 2,300 cases / week and 2,500 cases / week respectively . Given this cyclical trend , it is anticipated to peak in 2023 .

Selangor is the worst-hit State . As of Feb 11 this year , it had 6,870 cases , an increase of 141.4 per cent compared to last year .

Because all four dengue virus ( DENV ) serotypes co-circulate in Malaysia , the country is hyperendemic with dengue . That means people could get infected with dengue up to four times in their lifetime .

Worse , being infected with one serotype does not confer protection against the rest of the dengue serotypes . Patients who acquire a second dengue infection with a different dengue serotype are at an increased risk of severe dengue leading to shock , internal bleeding and even death .

A RISE IN CASES IS MULTIFACTORIAL

According to the Deputy Director of Health ( Public Health ) Datuk Dr Norhayati Rusli , the change in the dominant circulating dengue serotype or the “ serotype shift ” is a well-known reason for the occurrence of the dengue surge .

“ It has been observed that dengue cases will usually increase four to six months after a serotype shift due to the lack of immunity in the community towards the new dominant circulating serotype .

“ From the MoH ’ s surveillance monitoring , there was a shift of circulating dengue virus serotype from DENV 3 to DENV 4 since June 2021 . Since then , DENV 4 serotype has been the dominant circulating virus serotype in the environment .

“ Moreover , the opening of all sectors after the Covid-19 pandemic encourages population movement from dengue-prone areas to non-endemic dengue areas , which will introduce the dengue virus to a ‘ dengue naive ’ population . Furthermore , urbanisation with increased population density will aggravate the spread of dengue virus , especially in the highly-dense populated area .”

Climate change , she said , was another important factor , especially with alternating rainy and hot seasons . “ During the rainy season , containers or natural places such as leaves of plants will be filled with water , provide places for the Aedes to breed . During the hot season , the Aedes

Datuk Dr Norhayati Rusli

Dr Tahir Aris

mosquito becomes more active in its biting behaviour and it bites more humans , thus increasing the spreading of the dengue virus .”

She continued : “ Poor environmental cleanliness with the abundance of man-made containers provides suitable places for Aedes mosquitoes to breed . Human habits and littering behaviour are the main reasons for poor environmental cleanliness .

“ Lack of cooperation from certain households for indoor mosquito control activities will limit the effectiveness of interrupting dengue transmission in the local community .

“ The inadequate coverage of indoor mosquito control activities may result in prolonged dengue outbreak in the locality .”

Dengue outbreak after flooding is also a well-known phenomenon , as the stagnant water provides favourable habitats for mosquitoes to breed . The lag time is usually around three to four weeks before the occurrence of dengue cases .

DENGUE AWARENESS AND ADVOCACY

The public , said Malaysian Medical Association ( MMA ) President Dr Muruga Raj , must ensure that their home and surrounding areas do not turn into breeding grounds for the Aedes mosquito .

“ There is no point in carrying out fogging every other month or so if people aren ’ t doing their part .”

Dr Norhayati shared : “ By and large , public apathy towards health initiatives by MoH , including dengue-related activities , remain insignificant based on the warm response from the community during nationwide community engagement and dengue promotional activities .

“ Besides , MoH ’ s Health Education Division has mobilised a Special Health Education Team called Pasukan Khas Pendidikan Kesihatan ( PAKAT ) to dengue hotspots to raise community awareness about dengue prevention towards searching and destroy Aedes breeding sites .”

Integrated Enforcement activities , or Operasi Gempur Aedes , have been coordinated by the MoH and carried out monthly in various states .

Dr Tahir Aris , the Director of the Institute for Medical Research ( IMR ), added that the iDengue website , an initiative of the MoH and Agency Angkasa Negara , now includes data on dengue hotspots , daily and cumulative statistics , and many other helpful public resources .

“ It would benefit many researchers if the serotype statistics were available on the website . Information such as current locally commercialised dengue-related products and local research breakthroughs can also be included to raise public awareness .”

According to Dr Norhayati , advocacy events also play an essential role in getting public support .

“ For example , the commemoration of ASEAN Dengue Day on June 15 each year was endorsed by the 10th ASEAN Health Ministers Meeting in 2010 .”

“ Last year , the theme for ASEAN Dengue Day was ASEAN ’ s Resilience Against Dengue Amidst Covid-19 pandemic . Malaysia launched the event in Malacca with activities to encourage community participation to keep the environment clean and reduce potential mosquito breeding places .”