Reemergence of dengue virus in Bangladesh: Current fatality and the required knowledge

Abstract

The current fatality of dengue among the Bangladeshi population has drawn the interest of the public health professionals primarily to focus on the environmental, social, and clinical reasoning as well the possible remedies. This year, in 2019, the dengue situation in Bangladesh has appeared with all its dreadful effects leading to the highest death cases due to dengue virus (DENV) infection. According to the Directorate General of Health Services report, this year (2019) the number of DENV-infected people has appeared to be around five times higher (approximately 50,000 cases so far) compared with the last year, 2018 (around 10,000 cases). The present review discussed the current epidemics of dengue infection in Bangladesh as well the possible means of disease curing in terms of general preventive concepts. However, besides the precise treatment of the dengue-affected patients, the knowledge on DENV genome and on the protective immunity against such reemerging disease is essential.

Keywords: Bangladesh; Dengue; Public health; Secondary infection.

Figure 1

Immunity against DENV triggers pathogenesis. Primary infection with DENV triggers the release of several cytokines and chemokines together with the activation of cell-mediated immunity and humoral immunity. The reinfection, especially with a different serotype, induces the heightened threat of developing severe dengue (DHF). While the primary infection imparts the cross-reactive protective immunity, the secondary infection may be oppositely pathogenic. The direct role for DENV serotype cross-reactive antibodies is shown in this model during the severe dengue outbreak. Besides, the serotype-specific T cells prevails the primary infection; however, during the secondary infection, the memory T cells recognize the conserved epitopes and thereby increase together with naïve serotype, leading to the severe dengue. DENV: Dengue virus, DHF: Dengue hemorrhagic fever

Figure 2

Model of the role DENV RNA in its pathogenesis using the mice model. DENV RNA is translated into three structural proteins and seven non-structural proteins. In the DENV serotypes 1, 2, and 4, the CD8+ T cell responses have been shown to be specific for the nonstructural proteins including NS3, NS4B, and NS5. In DENV3 serotype, the CD8+ T cell responses are specific both for the structural and nonstructural proteins; and the CD4+ T cells are reactive against structural protein, capsid, and the nonstructural proteins, NS3 and NS5 proteins. DENV: Dengue virus