Epidemiology of dengue disease in Malaysia (2000-2012): a systematic literature review

Abstract

A literature survey and analysis was conducted to describe the epidemiology of dengue disease in Malaysia between 2000 and 2012. Published literature was searched for epidemiological studies of dengue disease, using specific search strategies for each electronic database; 237 relevant data sources were identified, 28 of which fulfilled the inclusion criteria. The epidemiology of dengue disease in Malaysia was characterized by a non-linear increase in the number of reported cases from 7,103 in 2000 to 46,171 in 2010, and a shift in the age range predominance from children toward adults. The overall increase in dengue disease was accompanied by a rise in the number, but not the proportion, of severe cases. The dominant circulating dengue virus serotypes changed continually over the decade and differed between states. Several gaps in epidemiological knowledge were identified; in particular, studies of regional differences, age-stratified seroprevalence, and hospital admissions.

Protocol registration: PROSPERO #CRD42012002293.

Figure 1. Map of Malaysia.

Malaysia is a federation separated into two regions by the South China Sea. There are 11 states and two federal territories on Peninsular Malaysia and two states and one federal territory in East Malaysia. The Peninsular states are divided into districts. On Borneo, the Sabah and Sarawak districts are grouped into divisions.

Figure 2. Results of literature search and evaluation of identified studies according to PRISMA.

All references identified in the on-line database searches were assigned a unique identification number. Following the removal of duplicates and articles that did not satisfy the inclusion criteria from review of the titles and abstracts, the full papers of the first selection of references were retrieved either electronically or in paper form. A further selection was made based on review of the full text of the articles. EMBASE, Excerpta Medica Database; PRISMA, preferred reporting items of systematic reviews and meta-analyses; WHO IMSEAR, World Health Organization Index Medicus for South-East Asia Region; WHO WHOLIS, World Health Organization Library Database; WHO SEAR MALAYSIA, World Health Organization Regional Office for Southeast Asia Malaysia; WHO WPRO, World Health Organization Western Pacific Region.

Figure 3. Reported dengue disease cases and deaths in Malaysia 2000–2011 , , , , –.

(A) Number of reported dengue disease cases (incidence per 100,000 population shown as numbers for the total cases only). (B) Number of reported deaths. (C) CFRs. The total annual number of dengue disease cases reported in Malaysia increased between 2000 and 2010 and decreased in 2011. Between 2000 and 2010, the incidence rate of dengue disease was consistently high (above 125 per 100,000 population). The majority of dengue disease cases were reported as DF and the ratio of DF to DHF cases remained fairly constant. The number of annual deaths from dengue disease increased between 2000 and 2010. However, after 2000 the CFR for DF+DHF remained fairly constant. CFR, case fatality rate; DF, dengue fever; DHF dengue haemorrhagic fever.

Figure 4. Serotype distribution in Malaysia.

(A) National data 2000–2012 , . (B) 2012 data (to 12 July 2012) by state* via the Sentinel Surveillance System . *One patient in Sarawak was infected with DENV-1 (not shown on graph). National data (A) demonstrated that the dominant DENV serotypes circulating in the country changed continually throughout the period of 2000 to 2011. DENV-4 was less prevalent than the other three serotypes and constituted <20% of the serotypes for all years. Regional data from 1 January 2012 to 12 July 2012 reported via the Sentinel Surveillance System (B) showed a heterogeneous distribution of DENV serotypes in the separate states. DENV, dengue virus.