Epidemiology and challenges of dengue surveillance in the WHO South-East Asia Region

Abstract

Dengue poses a significant health and economic burden in the WHO South-East Asia Region. Approaches for control need to be aligned with current knowledge on the epidemiology of dengue in the region. Such knowledge will ensure improved targeting of interventions to reduce dengue incidence and its socioeconomic impact. This review was undertaken to describe the contemporary epidemiology of dengue and critically analyse the existing surveillance strategies in the region. Over recent decades, dengue incidence has continued to increase with geographical expansion. The region has now become hyper-endemic for multiple dengue virus serotypes/genotypes. Every epidemic cycle was associated with a change of predominant serotype/genotype and this was often associated with severe disease with intense transmission. Classical larval indices are widely used in vector surveillance and adult mosquito samplings are not implemented as a part of routine surveillance. Further, there is a lack of integration of entomological and disease surveillance systems, often leading to inaction or delays in dengue prevention and control. Disease surveillance does not capture all cases, resulting in under-reporting, and has thus failed to adequately represent the true burden of disease in the region. Possible solutions include incorporating adult mosquito sampling into routine vector surveillance, the establishment of laboratory-based sentinel surveillance, integrated vector and dengue disease surveillance and climate-based early warning systems using available technologies like mobile apps.

Medical practitioner’s knowledge on dengue management and clinical practices in Bhutan

“…This is evident with 44% of the respondents having never seen dengue in their professional career. In Bhutan, dengue transmission only occurred in Chukha district (Fig 3) from 2004 to 2012 [27]. Eventually, it spread to eight new districts by the end of 2018, and a further 10 districts in 2019 [28].…”

Clinical predictors of severe dengue: a systematic review and meta-analysis

“…Only adults aged 9-45 years living in an area of ≥ 70% dengue prevalence, and whose serostatus is positive for past dengue infection are recommended for immunization [6]. Due to the challenges associated with the need to collect information on the burden and seroprevalence profiles of the local population, and the recent reports of vaccine-related severe dengue and deaths, the use of the dengue vaccines is not widespread [9]. Therefore, rapid identification of severe cases and appropriate clinical management remains the mainstay to avoid dengue-related case fatalities.…”

Nationwide Distribution of Dengue Virus Type 3 (DENV-3) Genotype I and Emergence of DENV-3 Genotype III during the 2019 Outbreak in Bangladesh

“…DENV is a member of the genus Flavivirus of the family Flaviviridae , and it contains four serotypes (DENV-1, -2, -3, and -4) which are further differentiated into genotypes. At present, the WHO Southeast Asia Region is considered hyperendemic for multiple DENV serotypes/genotypes [ 2 ]. Although a wide range of clinical manifestations represented by fever are seen in DENV infection in humans, secondary heterotypic DENV infection often results in severe disease previously known as dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) [ 3 ], which is mediated by antibody-dependent enhancement of disease [ 4 ].…”

“…In Bangladesh, a large outbreak due to DENV-3 genotype II occurred in 2000 with more than 5000 hospitalized cases and continued until 2002 [ 2 , 7 , 8 ]. Thereafter, dengue was found at low frequency until 2016, with DENV-2 being recorded as the predominant causative virus, followed by DENV-1 [ 8 , 9 , 10 ].…”