Survey of Dengue Knowledge and Prevention Practices Associated with Sociodemographic Status: A Cross-Sectional Study Among the Community Living in an Urban Area of Selangor, Malaysia

Dengue is one of the most prevalent public health issues in tropical and subtropical countries. Over the decades, dengue has flourished dramatically, with approximately 50% of the global population (>2.5 billion people) at risk of infection (WHO 2019). Transmitted by Aedes aegypti (L.) and Ae. albopictus (Skuse), dengue can occasionally develop into a severe dengue stage known as dengue hemorrhagic fever, which can cause severe complications and potential death in humans (Mohapatra and Aslami 2016). At present, no specific medications are available to cure the disease.

Earlier studies found that individuals with little knowledge of dengue demonstrated fewer prevention practices compared with individuals with more knowledge of dengue (Chandren et al. 2015, Wong et al. 2015). In contrast, other studies showed no significant association between knowledge of and practices for dengue (Hairi et al. 2003, Yboa and Labrague 2013). To date, only 2 studies have been conducted in urban areas of Selangor (Ghani et al. 2019) and Kuala Lumpur (Rozita et al. 2006); however, the findings were inadequate due to lack of sample size. Therefore, this study with a relatively higher sample size focused on exploring the association of sociodemographic status towards knowledge and prevention practices for dengue.

The data in the study were collected from May to July 2019 in selected community areas located in Petaling Jaya of Selangor, Malaysia. The sample size was calculated based on the number of participants stated in a previous study by Ghani et al. (2019). With a 20% refusal rate (Rozita et al. 2006), a total of 550 participants initially approached, resulted in the real sample size of 441 individuals (= 80.2%). During the visit to each household, only the head of the household was interviewed. If the head of household was unavailable, other eligible family members were randomly selected provided they followed some inclusion criteria such as age (>18 years old), local resident, and able to understand the questions asked by the interviewer. All interviewers that participated in this study were trained by the experts for 2 wk before the interview session started.

The questionnaire used in this study was the improved version of the questionnaire used in previous research (Chandren et al. 2015). Knowledge related to dengue section consists of 6 parts: 1) dengue and Ae. aegypti and Ae albopictus characteristic; 2) transmission; 3) signs and symptoms of dengue hemorrhagic fever; 4) signs and symptoms of dengue; 5) prevention practices for dengue; and 6) treatment, cure, and precautionary measures for dengue. The scale for the measurement of knowledge section consisted of 44 items. For each statement, participants could choose between 3 response categories: “yes,” “no,” and “don't know.” For the analyses, participants were scored as 1 for a correct response and 0 for an incorrect or “don't know” response. Several negatively worded items were reversed and recoded during the data analysis process. Possible scores ranged from 0 to 44. Higher scores indicated greater knowledge about dengue.

Meanwhile, the self-reported practices of dengue preventive measures section consisted of 2 parts: 1) preventive measures reducing mosquito breeding habitats; and 2) preventive measures reducing mosquito bites were assessed, using items 9 and 5, respectively. A penalty point was assigned for each option, as 0 for “not at all” and “not applicable,” 1 for “rarely,” 2 for “sometimes,” and 3 for “often” responses. The questionnaire was written in bilingual language (i.e., English and Malay language). The medium of the interview was in Bahasa Malaysia, the national language. Before the questionnaire was released to the participants, both the validity and reliability of the questionnaire were checked by the experts. A preliminary study among 20 public participants was carried out to ensure that the questionnaire carried effective, efficient, reliable, and valid data.

Data obtained in the study were analyzed using the Statistical Package for the Social Sciences (SPSS) program for Windows version 20.0 (SPSS, Chicago, IL). The univariate analysis of chi-square test was performed to determine the significant association between the independent variable (sociodemographic characteristics) and dependent variables (high and low scores of knowledge and self-reported dengue prevention practices). All significant values (2-tailed P-value < 0.05) in the univariate analyses were entered into the multivariate logistic regression analysis. Odds ratio (OR), 95% confidence intervals (95% CI), and P-values were calculated for each independent variable.

Overall, majority of participants had good knowledge, including general information of dengue and its vectors, transmission, signs and symptoms, prevention practices, and curability of the disease (Table 1). The results in Table 2 showed that more than half of the participants over 40 years old (57.1%) had a total knowledge score range of 32–44, compared with 39.5% in the 25–39 years age group and only 18.8% in the 18–24 years age group. More than 100 of the participants who worked as professional and managerial (53.5%) and most of the students (81.2%) had a total knowledge score range of 7–31. Our findings showed that less than half of the participants who had a tertiary education attainment (44.7%) had a total knowledge score of 32–44, while more than half of the participants who had a secondary and below education (63.1%) had a lower total knowledge score of 7–31. Participants whose average monthly household income was more than MYR3,000 (US$750.00) (51.6%) had a total knowledge score of 32–44, compared with participants whose average monthly household income was below MYR3,000 (33.2%). Results obtained from multivariate logistic regression showed that the participants over 40 years old were more likely (OR = 4.210, 95% CI = 1.652–10.733, P = 0.003) to have better dengue knowledge compared to the 18–24 years age group.

Meanwhile, there was a significant difference between dengue prevention practices and age of the participants (P < 0.05). Over half of both the 25–39 years age group (58.5%) and >40 years age group (57.1%) scored high, between 26 and 42, while only 40.6% of the 18–24 years age group scored in that range. Similarly, there was also a significant difference between the dengue prevention practices and average monthly household income (P < 0.05). The participants (61.5%) whose average monthly household income was more than MYR3,000 (61.5%) had a higher percentage of total dengue prevention practices score of 26–42 compared with those whose average monthly household income was below MYR3,000 (47.3%). Further analysis of multivariate logistic regression test indicated that participants whose average monthly household income was more than MYR3,000 were more likely (OR = 1.607, 95% CI = 1.059–2.438, P = 0.026) to perform more practices of dengue prevention compared with participants whose average monthly household income was below MYR3,000 (Table 2). The results regarding the practice of preventive measures for reducing mosquito breeding habitats and mosquito bites revealed that more than half of the participants often (>4 times) treated their stored water (18.1%) and checked for mosquito larvae inside and outside the house (28.8%).

In agreement with studies reported in the Philippines (Yboa and Labrague 2013), Cambodia (Kumaran et al. 2018), and Thailand (Swaddiwudhipong et al. 1992), the results of this investigation demonstrated that a majority of the participants were knowledgeable about the concept of dengue, the morphological characteristics of Ae. aegypti and Ae. albopictus, and the suitable habitats of these mosquitoes. Good knowledge of the mosquito vectors and signs and symptoms of dengue are important in identifying the disease and in seeking early and appropriate medical treatment to save lives (Ibrahim et al. 2009). Also interesting were the significant associations between prevention practices and average monthly household income. The results of logistic regression analysis found a significant association between the participants who earned a higher average monthly household income (>MYR3,000) and self-practices of dengue prevention compared with the participants who earned less. This could be due to the financial stability factors that allowed them to afford facilities or tools that aid in performing more practices of prevention measures such as hiring a professional or private pest control or installing screen windows in their house. In addition, the results of the study suggest that there was no significant association between knowledge of dengue and prevention practices, which is in agreement with similar studies (Hairi et al. 2003, Yboa and Labrague 2013). Both studies concluded that knowledge alone is not necessarily a predictor of good practices. The insignificant association between knowledge and dengue prevention practices found in the present study suggested that the support from government or private organization is needed as it could facilitate in initiating, designing, and implementing massive education programs or other services for a better dengue management throughout Malaysia.

We thank field assistants for their hard work to gather all the data needed for this study. The study was funded by the Research University Grant–UM Cares grant (Grant No. RU013-2017P), Postgraduate Research Grant–PPP (Grant No. PG160-2015B), and Faculty Research Grant–FRG (Grant No. GPF013C-2018).