Understanding the future of dengue in Malaysia: Assessing knowledge, attitude, and homeowner practices in mitigating climate-driven risks

Climate change and Dengue

Climate change has emerged as a pressing global issue, with extensive consequences on environmental, social, and public health aspects. The increasing intensity of extreme weather conditions, rising temperatures, and shifting precipitation patterns are exacerbating existing challenges leading to a range of adverse health outcomes, including the spread of vector-borne diseases. These diseases are particularly susceptible to the impacts of climate change due to alterations in vector habitats and disease transmission dynamics. The modified environment creates favourable conditions for vector proliferation and disease transmission, leading to increased incidence and geographic spread of these diseases (Vieira et al., 2024).

Malaria and Dengue fever are among the most prevalent vector-borne diseases worldwide, with an estimated incidence of 249 million cases of Malaria (WHO, 2023) and 100-400 million cases of Dengue in 2022 (WHO, 2024). Warmer temperatures are expanding the geographic range of mosquitoes responsible for transmitting malaria (Anopheles) and dengue (Aedes). Cases are now being reported more frequently in countries with cooler climates, where they were rarely reported previously (Lenharo, 2023). Heavy rainfall and flooding create conducive environments for mosquito breeding. Stagnant water pools formed during floods serve as their ideal breeding.

Dengue incidence

Malaysia has entered the elimination phase of malaria control, but Dengue fever remains a growing problem (Sa-Ngamuang et al., 2023; Md Taib & Atil, 2023). Dengue fever is a prominent public health challenge which often affects the tropics. It is brought upon by the flavivirus transmitted by the Aedes aegypti mosquito. In Malaysia, despite various control measures, the incidence of dengue continues to rise, (Chem et al., 2024), with a 235.6% increase in cases reported between December 31, 2022, and June 10, 2024 (Tan & Gerard, 2024). A retrospective study conducted by Bujang et al. aimed to investigate the trend in dengue cases in Malaysia revealed a staggering 1561.3% increase from 1995 to 2014. The study also reported an incidence rate of 161.5 per 100,000 population in 2010 and is projected to rise to 940.0 per 100,000 population by 2040 (Bujang et al., 2017).

As of May 10, 2024, a total of 56,884 dengue cases have been reported, covering the period from December 31 of the previous year up to the present day. The daily average for new cases stands at 334 (see Table 1). From 2022 to 2024 (accumulated cases from January to May), there was a substantial increase of 315.23% in dengue cases (Wan-Fei et al., 2023) (See Figure 1). Similarly, from 2023 to 2024 (accumulated cases from January to May), there was a notable increase of 124.20% in dengue cases (Ministry of Health Malaysia 2023).

Figure 1. Dengue cases from 2022 to 2024 (Jan to May).

Source from National Crisis Preparedness and Response Centre (CPRC), Ministry of Health Malaysia (MOH).

Current established Dengue prevention and control measures by the Ministry of Health, Malaysia

States like Selangor, with densely populated urban areas, report the highest incidence rates, exacerbated by poor housing conditions that contribute to mosquito proliferation. The steep rise in dengue cases can be attributed not only to environmental factors but also to the limitations of current prevention measures. PKD in Selangor is grappling with a substantial burden as the region contends with a surge in dengue cases. As of May 12, 2024, 29,678 cases have been reported, accompanied by the identification of 124 hotspot areas (idengue.mysa.gov.my, 2024).

PKD employs several commendable initiatives in managing the dengue situation in their locality (Rusli et al., 2022), encompassing early detection facilitated by the integrated reporting system through e-notifikasi, strict enforcement of reporting protocols, and targeted destruction of breeding sites. Doctors are mandated to report dengue cases within 24 hours under the “Act 342 Prevention and Control of Infectious Diseases Act 1988,” with non-compliance incurring a fine of RM 1000. Once a case is reported, the PKD registers reported cases to assess outbreak potential, defined as two cases in a locality or one case residing 200 meters from the index case or first case within 14 days.

In response to outbreaks, the PKD conducts fogging and search-and-destroy operations. Health officers will conduct fogging within a 400-meter radius from the reported outbreak’s address, repeating these cycles every 5-7 days which continues for 2 weeks after the outbreak. They also identify breeding sites, with RM 500 penalties for house owners where breeding sites were identified. Larviciding activities are initiated and repeated every 3-5 days until 2 weeks after the resolution of the outbreak.

However, if these areas continue to have reported cases after 30 days, they will be considered as Dengue Hotspots and will be published on the “idengue” website. PKD will work closely with these communities, by meeting them weekly for weekly presentation of cases and education. The State Health Department or the Jabatan Kesihatan Negeri (JKN) will also encourage the community to do clean-up drives or the “Gotong Royong” in Malay ( Figure 2).

Figure 2. Dengue Outbreak Management, PKD Gombak Malaysia.

PKD = Pejabat Kesihatan Daerah (District Health Office), E-notifikasi = online notification system used for reporting certain communicable diseases, JKN = Jabatan Kesihatan Negeri (State Health Department).

Source: Pelan Strategik Pencegahan Dan Kawalan Denggi Kebangsaan 2022-2026.

Environmental factors are key determinants in the proliferation of dengue vectors and the subsequent outbreak of the disease. Poor waste management practices, including irregular garbage collection and improper disposal of waste, contribute significantly to the breeding of mosquitoes. In urban areas, where population density is high, and infrastructure may be inadequate, stagnant water in discarded containers, blocked drains, and neglected water storage vessels become ideal breeding sites for Aedes mosquitoes.

Collaborative efforts between government agencies, local authorities, community organisations, and residents are essential to creating sustainable solutions that mitigate the environmental factors contributing to dengue outbreaks.

The strain on resources is palpable, with the PKD stretched thin in its efforts to combat the escalating dengue crisis. Hotspot areas, identified as focal points of dengue transmission, continue to report cases over extended periods, indicating persistent challenges in eradication efforts. Compounding these challenges is the overwhelming caseload experienced during massive outbreaks, leading to lapses in essential activities like active case detection and comprehensive environmental risk assessments (Tee et al., 2019).

This scenario underscores the urgent need for bolstered resources, strategic interventions, and enhanced collaboration between stakeholders to effectively address the dengue epidemic in Selangor. Without concerted efforts to strengthen the capacity of the PKD and implement targeted measures to curb dengue transmission, the region may continue to face prolonged and severe public health challenges associated with the disease.

The government has invested significant resources in vector control efforts and imposed fines for failing to eliminate mosquito breeding grounds. However, many of these breeding sites are located within private homes, where government interventions are limited. The real issue lies deeper: at the heart of the problem are the residents’ practices regarding dengue prevention. Effective prevention starts with homeowners taking responsibility for eliminating potential breeding grounds on their properties. But for these practices to be adopted, residents must first recognize their importance. This requires not only knowledge about dengue prevention but also a shift in attitude. Residents must perceive their susceptibility to infection and understand the severity of the disease and its impact on their families and daily lives. Only when they fully grasp these risks can they embrace preventive measures and protect their communities from dengue.

Gaps in current Dengue control & prevention practice

A study by Zaki et al. involving 847 residents in a Selangor district, reported that the majority have a good understanding of dengue fever (97.1%) and its correlation with climate factors (90.6%). A significant percentage expressed willingness to contribute to reducing dengue cases in their locality (91.5%). However, over half of the respondents (64%) do not regularly inspect potential hotspots in their area, and not everyone is eager to participate in cleanup initiatives (Zaki et al., 2019). Correct understanding or knowledge does not necessarily result in the adoption of correct attitudes and practices for dengue prevention A scoping review done by Rahman et al., on identifying the barriers to knowledge, attitude and practices of dengue prevention in the community involving 349 articles from 2010-2018 suggests that factors interfering with dengue prevention practices are divided into two, namely:

To mitigate the ongoing dengue problem, the government must prioritize densely populated areas like Selangor and Kuala Lumpur, focusing not only on these environmental factors but also on the internal factors that drive residents’ prevention practices. An effective strategy for combating dengue requires addressing residents’ understanding of their vulnerability to infection and the severity of its potential impact. The Health Belief Model (HBM), a widely used framework in public health, provides valuable insights into how individuals’ perceptions influence their health-related behaviors. It explains that people are more likely to adopt preventive measures when they perceive themselves to be at risk (perceived susceptibility) and understand the serious consequences of the disease (perceived severity). In the context of dengue prevention, if residents recognize their vulnerability to infection and believe that the impact of dengue can be severe, they are more likely to take appropriate actions, such as eliminating mosquito breeding sites and using protective measures. According to Glanz et al. (2008), the HBM underscores the importance of addressing both external conditions and internal beliefs to effectively promote behavior change and eventually for this particular case, reduce the spread of dengue ( Figure 3).

Figure 3. Health belief model.

Residents of low-income communities may underestimate their susceptibility to the virus. Environmental factors such as overcrowded living conditions and poor waste management in these areas create ideal breeding grounds for mosquitoes. They are the ones vulnerable to the financial burden of contracting dengue. A single day of lost income due to illness can have dire economic consequences for households already struggling to make ends meet.

Dengue fever is often referred to as a disease prevalent in poor areas, and closely linked with impoverished populations. The World Health Organization categorises dengue fever as one of the neglected tropical diseases (NTDs), which are indicative of poverty, and recommends interventions targeted at populations in poverty-stricken and marginalised communities to address dengue (Mulligan et al., 2015).

In Malaysia, where dengue remains a significant public health threat, there is a notable scarcity of data on the national understanding of dengue infection, as well as on public attitudes and preventive practices. Therefore, this study aimed to assess the knowledge, attitudes, and preventive practices of a low-income community consisting of 16,000 residents in a densely populated area of Kuala Lumpur. The results of this study are expected to contribute to the development of evidence-based community health intervention programs that specifically target homeowners’ preventive practices. These findings will enhance our understanding of the factors influencing knowledge, attitudes, and practices among low-income, community-dwelling adults and provide public health authorities with crucial insights for prioritizing actions in similar settings across Malaysia.

Study design, population and sample size

Study design and setting

A community-based, cross-sectional study was conducted over 4 weeks in July 2024 among adult residents of four low-cost housing apartments under the People’s Housing Programme (Program Perumahan Rakyat or PPR) in the federal constituency in Kuala Lumpur, Malaysia. In 1998, the National Housing Department of the Malaysian Ministry of Housing and Local Government (Jabatan Perumahan Negara) developed the PPR to provide affordable housing for Malaysians of low socioeconomic status with a monthly household income below RM 3,000 (Goh et al., 2011).

The four participant PPRs in this study were PPR Sri Pantai, PPR Pantai Ria, PPR Kampung Limau and PPR Seri Cempaka. These PPRs were chosen for their proximity to the Klang River, which creates significant challenges for vector control due to stagnant water that serves as breeding grounds for Aedes mosquitoes. Our aim is to assess the community’s understanding of these risks to develop an effective health intervention for this vulnerable area.

Dengue has been confirmed in this community, as shown by the DENV-positive mosquito pools recorded in the table below based on a 2021 study by the National Institute of Health in collaboration with the University of Malaya (Wan et al., 2021). We have specifically chosen this community for the survey because such areas, especially near water bodies, are prone to recurrent outbreaks, highlighting the necessity of continuous monitoring and targeted interventions ( Figure 4).

Figure 4. Distribution of 51 DENV-positive pools collected in 26 localities.

Source: 2021 study by the National Institute of Health in collaboration with the University of Malaya (Wan et al., 2021).

Sampling frame, design and sample size

Each of these PPRs comprises multistorey apartments that are labelled as blocks. PPR Sri Pantai has two 21-storey blocks namely, Block 100 and 102 with 20 units on each floor. Each of the four blocks A, B, C and D of PPR Pantai Ria has 17 floors, with a total of 20 units per floor. Block 96 and Block 94 of the PPR Kampung Limau are 17-storeyed with 20 units per floor. The Seri Cempaka PPR consists of two 17-storey blocks, ‘E’ and ‘F’. To minimize sampling bias, a structured design was used, with the sampling frame drawn from four PPR areas. Stratified random sampling ensured proportional representation from all floors of each apartment block. Data collection included weekends to ensure broader resident participation. This approach helped capture a diverse and representative sample, reducing the risk of bias related to availability or uneven representation.

The sample size is calculated using the Krejcie and Morgan sample size calculation method (Krejcie and Morgan, 1970) to ensure it is representative of the entire population.

Sample size calculation: The formula for the Krejcie and Morgan sample size calculation is as follows:

Using this formula, the following sample sizes have been calculated for the populations. The estimated sample size for each of the PPRs based on the total population is shown in Table 2.

Questionnaire

The structured questionnaire was adapted from the validated Malay version developed by Mac Guad et al. (2021). Permission to use the questionnaire and scoring system was obtained from the authors. The questionnaire was divided into four sections:

The KAP scores were calculated, with high KAP defined as achieving 80% or more of the maximum possible score, and low KAP defined as scores below this threshold (Elia-Amira et al., 2023).

Categorisation of knowledge, attitude, and practices

Respondents’ dengue knowledge, attitude, and practices (KAP) were categorised as “Good” or “Poor” based on predefined scoring criteria ( Table 4).

Below are the criteria used for each domain:

Data analysis

Data analysis was conducted using IBM-SPSS Statistics version 25. Descriptive statistics, including frequencies and percentages, were used to describe the population characteristics and summarize participants’ knowledge, attitudes, and practices (KAP) related to dengue prevention. Logistic regression was used to identify potential predictors among the sociodemographic variables. Variables with a significance level of p ≤ 0.25 in univariate analysis were further analyzed using multiple logistic regression to determine independent predictors of high or low KAP levels. A p-value of ≤ 0.05 was considered statistically significant.

Ethical considerations

Ethical approval for this study was obtained from the Institutional Review Board (IRB) of Taylor’s University Center for Research Management, with approval number HEC 2024/179, granted on June 20, 2024. The study adhered to the ethical principles outlined in the Declaration of Helsinki. Written informed consent was obtained electronically via a Google form. Participants were fully informed about the study’s purpose, and their rights to privacy and confidentiality were upheld. All collected data were anonymized to protect participants’ identities, and they were notified of their right to withdraw from the study at any time without any repercussions.

A. Sociodemographic characteristics

The study collected 1,636 responses, with the majority being females (56.8) and Malays (78.3%). Most respondents were married (70.9%) and had secondary level education (64.4%). Of the total population, 47.35% are not working, with almost half being housewives at 26.3%, while the remainder consists of those who are either retired at 10.3% or unemployed at 10.7%, A significant portion earned less than RM2500 monthly (62.4%) (Table 3) I (extended data).

B. Knowledge, attitude and prevention practices

In this community, 76.7% of participants exhibited poor knowledge and 83.1% had a negative attitude towards dengue, despite 66.7% demonstrating good prevention practices ( Table 4).

Knowledge

Most residents (77.7%) had limited knowledge about dengue. Most of the participants had correctly identified the symptoms, i.e. fever (88.9%) and nausea (68.2%) as symptoms, but wrongly identified cough (47.1%) and swollen glands (32%). Majority of the residents correctly identified mosquito behavior, but 43.3% incorrectly believed there’s a specific treatment for dengue. Most recognized the importance of rest (82.6%) and hydration (90.2%) for recovery, and 90.8% were aware of fines for mosquito larvae on their property (Table 5) (extended data).

Attitude

In terms of attitudes towards dengue prevention, a significant portion of residents (62.3) believe that killing the mosquitoes is the only way to prevent infection, with 66.8 percent trusts in fogging as a way of control. And the majority agrees (74.6%) that fines help in the control and believes that dengue is preventable (60.2%) ( Table 6).

Practice

Most residents engaged in good dengue prevention practices. Out of the 11 dengue practices, majority about 75% of the respondents answered yes to all the questions, except with the Abate use (54.4%) ( Table 7).

C. Predictors of KAP

Knowledge predictors

To identify predictors of dengue knowledge, attitudes, and preventive practices, we initially conducted a univariate logistic regression analysis. Variables that demonstrated a significance level of 0.25 were subsequently included in a multivariate analysis. Among all tested variables, only PPR (Public Housing Program), marital status, and education level emerged as independent predictors of dengue knowledge.

The analysis revealed that residents from PPR Pantai Ria were 1.7 times more likely to have a higher level of dengue knowledge compared to those from PPR Sri Pantai (p = 0.004). Similarly, residents from PPR Sri Cempaka and PPR Kampung Limau demonstrated 2.8 times (<p = 0.001). and 3.2 times (p ≤0.001) higher odds, respectively, of possessing greater dengue knowledge relative to those from PPR Sri Pantai.

In terms of marital status, married residents were 3 times more likely to have good dengue knowledge compared to widowed or divorced residents (p = 0.007). This suggests that marital status, alongside location, plays a critical role in influencing residents’ awareness and understanding of dengue prevention and control.

Educational attainment is also an important predictor of dengue knowledge (p value≤0.002), even though no individual education level (primary, secondary, tertiary) showed a statistically significant association (Table 8) (extended data).

Attitude predictors

All variables were initially tested using univariate logistic regression to assess predictors of dengue-related attitudes, and those with a significance level of 0.25 were included in a multivariate analysis. Among the variables examined, only the PPR community was identified as a significant predictor of dengue attitude.

Residents of PPR Pantai Ria were found to be 2.7 times more likely to demonstrate a positive attitude towards dengue prevention compared to those from PPR Sri Pantai (p value≤0.001), while PPR Kampung Limau were 2 times more likely to exhibit favorable attitudes towards dengue prevention as compared to residents of PPR Sri Pantai (p value ≤0.001) (Table 9) (Extended data).

Preventive Practices predictors

To identify predictors of dengue preventive practices, we performed a univariate logistic regression analysis on all variables, followed by multivariate analysis for those with a significance level of 0.25. Our findings revealed three significant predictors of good preventive practices: PPR community, marital status, and previous infection with dengue.

In terms of the PPR communities, residents of PPR Pantai Ria were 2.7 times more likely to engage in dengue preventive practices compared to those from PPR Sri Pantai. Similarly, residents from PPR Sri Cempaka and PPR Kampung Limau had odds ratios of 1.9 (p < 0.001) and 1.7 (p < 0.001), respectively, for practicing dengue prevention relative to PPR Sri Pantai.

Marital status was another significant predictor. Both single and married individuals had higher odds of practicing dengue prevention compared to widowed or divorced residents, with odds ratios of 1.9 for singles (p = 0.015) and married individuals (p = 0.007), respectively.

Interestingly, prior infection with dengue was also a significant predictor. Those who had previously been infected with the virus were 1.5 times more likely to engage in preventive practices compared to those who had never experienced dengue (p = 0.047). This suggests that personal experience with the disease can enhance adherence to preventive measures (Table 10) (extended data).

Ethical considerations

Ethical approval for this study was obtained from the Institutional Review Board (IRB) of Taylor’s University Center for Research Management, with approval number HEC 2024/179, granted on June 20, 2024. The study adhered to the ethical principles outlined in the Declaration of Helsinki. Written informed consent was obtained electronically via a Google form, ensuring voluntary participation. Participants were fully informed about the study’s purpose, and their rights to privacy and confidentiality were upheld. All collected data were anonymized to protect participants’ identities, and they were notified of their right to withdraw from the study at any time without any repercussions.