692 Indian Journal of Public Health Research & Development, May 2020, Vol. 11, No. 05 Assessing Demographic Distribution of Dengue Infections in District,

Md. Shahin Mia1, A.C. Er2, Rawshan Ara Begum3, Joy Jacqueline Pereira4, Ferdoushi Ahmed5

1School of Economics, Finance and Banking (SEFB), Universiti Utara Malaysia (UUM), 06010, Sintok, , Malaysia, 2School of Social, Development and Environmental Studies, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, , Malaysia, 3Center for Water Cycle, Marine Environment and Disaster Management (CWMD), Kumamoto University, 2-39-1 Kurokami, Kumamoto, Japan, 4Southeast Asia Disaster Prevention Research Initiative (SEADPRI), Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia, 5Faculty of Economics, Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand

Abstract This study aims to assess the trends of dengue incidence and socio-demographic characteristics of reported dengue cases in Seremban district, Malaysia during the last decade. Secondary data on reported dengue cases during 2003-2011 were collected from the District Health Office, Seremban. Trend analysis was conducted to assess the status of dengue incidence and demographic distribution of the disease in the district. Annual incidence rates of the disease were also calculated and compared. The district experienced a total of 11,936 dengue infections during 2003-2011. It was found that majority of the reported cases were among the Malays (62%), followed by Chinese (17%) and Indians (15%). The age-specific incidence rate was highest in young adult and adult group (15-44 years), followed by middle-age group (45-59 years). The analysis also revealed that majority of the reported cases (on average, 79% per year) came from urban areas of the district which highlights the fact that dengue is still an urban public health problem in Seremban. The study findings provide the critical data and information on trends of dengue incidence and socio-demographic characteristics of reported dengue cases which might assist the public health authorities to achieve dengue mortality and morbidity reduction goals in the district.

Keywords: Dengue incidence, demographic distribution, Seremban, Malaysia.

Introduction The dengue infection usually begins with a sudden onset of high fever, a severe frontal headache, pain behind Dengue is a mosquito-borne viral infection which the eyes, muscle and joint pains, nausea, vomiting, and can be caused by one of the four antigenically distinct rash(5,6). The infection can manifest as DHF or DSS dengue viruses namely, DENV-1, DENV-2, DENV- with plasma leakage, severe abdominal pain, respiratory 3, and DENV-4(1- 3). From the clinical perspective, a distress, spontaneous bleeding, rapid breathing, fatigue, dengue infection is usually classified as dengue fever hypotension and organ impairment (7).Currently, there (DF), dengue hemorrhagic fever (DHF) or dengue shock is no specific medication for DF/DHF(8,9). The patients syndrome (DSS) according to severity of the disease (4). are treated with paracetamol, oral rehydration and IV fluids in order to maintain the volume of the patient’s body fluid(10). Moreover the patient suffered from DHF or DSS is considered a medical emergency and requires Corresponding Author: hospitalization in intensive care unit.(10, 11) Md. Shahin Mia School of Economics, Finance and Banking (SEFB), Dengueis found in tropical and sub-tropical regions Universiti Utara Malaysia (UUM), 06010, Sintok, around the world, mostly in urban and semi-urban Kedah, Malaysia areas(12,13). In recent years, dengue has become a major Indian Journal of Public Health Research & Development, May 2020, Vol. 11, No. 05 693 international public health concern in terms of morbidity burden of dengue from socio-demographic perspectives and economic impact(14). The disease is now endemic in that might be helpful in policy and decision making for 124 countries of the world and all four dengue viruses sustainable public health in Malaysia. are circulating in poor and developing countries in Asia, Africa and the Americas(15-18). WHO currently Material and Method estimates that there is 50-100 million dengue infections Seremban is one of the seven districts of the worldwide each year, 500,000 cases of DHF, and about Malaysian state of . It is the capital of (19) 2.5% of whom die . Southeast Asia and the Western the state and one of the most affected districts by dengue Pacific regions are particularly vulnerable to dengue infections in Malaysia. The hot and humid climate of due to rapid urbanization and high densities of dengue Seremban is favourable for Aedes mosquitoes to breed (20) vector . Recently, DHF has become a leading cause and survive. Moreover, rapid urbanization, infrastructure of hospitalization and death among children in most of development, very active construction sector for housing (12) the Asian countries . Approximately, 200,000 dengue and commercial buildings in the district play important cases have been reported annually during the last decade role in transmission and outbreaks of dengue. We (21) in Asia Pacific region . conducted a retrospective secondary-data based study Currently, DF is one of the major public health and collected annual data on reported cases of DF and problems in Malaysia(22,23). The incidence of DF and DHF and patients’ socio-demographic information in DHF in Malaysia has increased steadily during the Seremban during 2003- 2011. Reported cases included last decade(24). The disease is predominant in urban all the clinically diagnosed and laboratory-confirmed areas where majority of the country’s total population cases notified to public health authority in the district. resides(25). Seremban is one of the highly affected districts Data were extracted from record of the District Health by dengue infections in Malaysia. However the ongoing Office, Seremban. Trend analysis was conducted to burden of the disease in the district is not well studied. assess the status of dengue incidence from 2003 to This study aims to assess the trends of dengue incidence 2011. Annual incidence rates were also calculated and in Serembanduring the last decade. It also analyses compared for the nine-year period. Summary descriptive the socio-demographic characteristics of the reported statistics (viz. summation, mean, frequency, ratio and dengue cases in the district. To our knowledge, this percentage) were applied to analyze socio-demographic study is an important academic attempt to examine the characteristics of reported dengue cases.

Results and Discussions

Figure 1: Number of dengue cases and incidence rate in Seremban 694 Indian Journal of Public Health Research & Development, May 2020, Vol. 11, No. 05 Annual Incidence of Dengue: Figure 1 shows the and incidence rate per 100,000 populations in Seremban annual number of dengue (including DHF) cases in between 2003 and 2011. It was found that out of the Seremban between 2003 and 2011. The findings suggest total 11,946 reported cases, 11,288 (95%) were DF with that dengue incidence has followed a cyclical pattern (i.e. the remaining 648 (5%) being DHF. It was also found down-up-down-up) during the last decade. However, that the number of DF cases was substantially higher a total of 11,946 dengue cases were reported in the than that of DHF in each year during the last decade. district over a 9-year period. Incidence rate of dengue in The findings indicate that annual incidence rate of DF Seremban is also shown in figure 1. The findings showed in every 100,000 populations was substantially greater a great variation in yearly incidence rate of the disease (the range of 91.45-421.31)than that of DHF (the range during the last decade. The highest incidence rate of 5.62- 22.61)between 2003 and 2011. The DF/DHF (443.60 cases per 100,000 populations) was observed in ratios also reveal that DF was the predominant type the year 2003 while the lowest incidence rate was 97.07 of dengue illness in the district over the last 9 years. cases per 100,000 populations in 2011. The predominance of DF over DHF in the district was observed to be the greatest (45.5: 1) in the year 2004 and Distribution of Cases by DF and DHF: Table 1 the smallest (8.9: 1) in 2009. shows the distribution of dengue cases by DF and DHF

Table 1: Distribution of cases and incidence rate by DFand DHF in Seremban

Number of dengue cases Incidence rate per 100,000 populations Year Ratio (DF/DHF) DF DHF DF DHF 2003 1890 100 421.31 22.29 18.9: 1 2004 1547 34 332.76 7.31 45.5: 1 2005 1335 43 277.61 8.94 31.1: 1 2006 1123 77 225.96 15.49 14.6: 1 2007 1201 79 234.11 15.40 15.2: 1 2008 1350 51 255.44 9.65 26.5: 1 2009 948 106 174.49 19.51 8.9: 1 2010 1373 126 246.32 22.61 10.9: 1 2011 521 32 91.45 5.62 16.3: 1

Distribution of Dengue Cases According to Sex: male: female) ranged from 1.4: 1 to 2.1: 1 (table 2). The Table 2 presents the distribution of dengue cases and male/female ratios also reveal that there was a consistent incidence rate per 100,000 populations based on sex in trend of males having a higher incidence of dengue as Seremban for the period of 2003-2011. Of the total cases compared to females. reported in the district over the nine years period, 7305 (61%) were males and 4631 (39%) were females. It can Distribution of Dengue Cases Based on be also seen that majority of the reported cases per year Ethnicity: The distribution of dengue cases by ethnic were consistently male in the district between 2003 and group in Seremban between 2003 and 2011 is shown 2011. Moreover the findings indicate that the annual in figure 2. The findings revealed that while all ethnic number of male cases in every 100,000 populations was groups were infected by the disease the majority of the greater than that of female cases in the district during reported DF/DHF cases were among the Malays. It can the last decade. However, there was a great variation in be seen that the Malays constituted, on average, 62% yearly incidence rate of dengue in both male and female of notified cases per year in the district during the last population. The ratio of male cases to female cases (i.e. decade. The data show that the Chinese had the second Indian Journal of Public Health Research & Development, May 2020, Vol. 11, No. 05 695 highest proportion of dengue incidence in the district. shared the smallest portion (on average, 6%) of annual This ethnic group shared, on average, 17% of the yearly dengue incidence in the district. Majority of the dengue reported cases for the period of 2003-2011. The Indians cases under the other groups were foreign workers constituted an average of 15% of the annual reported mainly from Indonesia, Bangladesh and Nepal. cases of dengue during the last decade. The other groups

Table 2: Distribution of dengue cases and incidence rateaccording to sex in Seremban

Number of dengue cases Incidence rate per 100,000 populations Ratio Year Male Female Male Female (Male/Female) 2003 1144 846 494.81 389.32 1.4: 1 2004 936 645 390.65 286.16 1.5: 1 2005 833 545 336.02 233.91 1.5: 1 2006 770 430 300.43 178.65 1.8: 1 2007 868 412 327.92 165.93 2.1: 1 2008 934 467 342.50 182.49 2.0: 1 2009 625 429 222.97 163.12 1.5: 1 2010 874 625 304.11 231.48 1.4: 1 2011 321 232 109.52 83.88 1.4: 1

Figure 2. Distribution (%) of dengue cases based on ethnicity in Seremban

Distribution of Dengue Cases Based on Locality: the urban areas ranged from 62% to 98% highlighting The distribution of dengue cases according to locality the predominance of the disease in urban localities of in Seremban for the period of 2003-2011 is presented the district. The highest predominance (98%) of urban in figure 3. The findings reveal that dengue cases were incidence of dengue in the district was observed in the more prominent in urban areas of the district during year 2011. the last decade. The percentage of cases reported from 696 Indian Journal of Public Health Research & Development, May 2020, Vol. 11, No. 05

Figure 3. Distribution (%) of dengue cases based on locality in Seremban

Distribution of Dengue Cases According to Age: (64%) of dengue incidence in the district. However the Table 3 depicts the distribution of dengue infections middle-age group (45-59 years) constituted 16% of total according to age of the reported cases in Seremban reported dengue cases in the district. On the other hand between 2003-2011. It can be seen that the children (0- the proportion of dengue infections among older people 14 years) contributed 15% (1,759 cases) of total reported (60 years and above) was significantly low (5% of total cases in the district during the last decade. The analysis reported cases). shows that the adult (15-44 years) had the highest portion

Table 3: Distribution of dengue cases based on age in Seremban

Age Group Year 0-14 years 15-44 years 45-59 years 60 & above Total Dengue cases (%) Dengue cases (%) Dengue cases (%) Dengue cases (%) 2003 390 20% 1,280 64% 243 12% 77 4% 1,990 2004 283 18% 1,025 65% 206 13% 67 4% 1,581 2005 215 15% 852 62% 245 18% 66 5% 1,378 2006 175 14% 754 63% 229 19% 52 4% 1,210 2007 169 13% 846 67% 201 15% 64 5% 1,280 2008 173 12% 877 63% 260 19% 91 6% 1,401 2009 114 11% 685 65% 184 17% 71 7% 1,054 2010 165 11% 984 66% 269 18% 81 5% 1,499 2011 75 14% 384 69% 71 13% 23 4% 553 Grand 1,759 15% 7,687 64% 1,908 16% 592 5% 11,946 Total Indian Journal of Public Health Research & Development, May 2020, Vol. 11, No. 05 697 Conclusion Thailand. Dengue Bull. 2010; 34: 77- 88. The present study investigates the trends of dengue 5. Potts JA, Rothman AL. Clinical and laboratory incidence and socio-demographic distribution of the features that distinguish dengue from other disease in Seremban, Malaysia between 2003 and febrile illnesses in endemic populations. Trop 2011. 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