Dengue cases set to spike

PETALING JAYA: Dengue cases are on the rise and expected to peak this year, with the possibility of the case count surpassing last year’s 66,000 – which was about 151% higher than in 2021.

Health director-general Tan Sri Dr Noor Hisham Abdullah said the number of cases was expected to surge in 2023.

“Based on national data, the dengue trend is observed to follow a cyclical pattern with a dengue epidemic being reported every four to five years,” he told The Star.

Dengue epidemics were observed in 2014 and 2019, with an average of 2,300 cases per week and 2,500 cases per week reported, respectively.

“Dengue is rising as part of its cyclical trend, and it is anticipated to peak in 2023,” he added.

Dr Noor Hisham said there was a 150.7% increase in dengue cases between 2021 and 2022 and a 180% jump in deaths in that period.

Malaysia reported 66,102 dengue cases and 56 deaths in 2022 compared with 26,365 cases and 20 deaths in 2021.

“Similarly, the rising dengue trend this year is also observed in other countries in the region.

“The rising number of dengue cases is partly contributed to by the change in the dominant circulating dengue serotype or the ‘serotype shift’, which is a well-known reason for the occurrence of the dengue surge,” he added.

The “serotype” refers to a distinct variation within a species of virus.

Many states, such as Selangor and Sabah, were reporting a drastic hike in dengue cases late last year, as were countries in the region such as Vietnam and Laos.

Based on observations, dengue cases will usually increase in 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 ministry’s surveillance monitoring, there was a shift of circulating dengue virus serotype from DEN 3 to DEN 4 since June 2021. Since then, the DEN 4 serotype has been the dominant circulating virus serotype in the environment,” said Dr Noor Hisham.

He said other contributing factors were littering and poor environmental cleanliness, especially with containers being a suitable breeding ground for Aedes mosquitoes.

“Climatic change is another important factor, especially with alternating rain and hot seasons.

“During the rainy season, man-made containers or natural places, for example the leaves of plants that retain water, create potential places for the Aedes mosquito to breed.

“On the other hand, during the hot season, Aedes mosquitoes become more active and bite more humans, thus increasing the spread of the dengue virus,” he said.

Dr Noor Hisham said as more dengue cases were anticipated this year, the ministry expected commitment and cooperation from the community, local authorities, the private sector, non-governmental organisations and local volunteers in managing potential mosquito breeding places, especially in residential areas and public facilities.

He urged the community to adopt preventive practices, such as spending time to search and destroy any potential mosquito breeding spots inside and outside of their premises, carrying out cleaning activities regularly to keep the environment free from mosquitoes, and using mosquito repellent when outdoors or aerosol or mosquito netting to avoid getting bitten by mosquitoes.

Dr Noor Hisham also advised that larvicide be added to water retention containers that could not be emptied regularly.

He also urged those with fever to seek early treatment at the nearest health facility.