Dengue in a crowded megacity: Lessons learnt from 2019 outbreak in Dhaka, Bangladesh

Abstract

Dengue is a mosquito-borne viral disease commonly reported in the tropical regions of the world. The presence of two mosquito vectors (Aedes aegypti is highly urban, while A. albopictus is less urban) throughout the year makes dengue fever an endemic disease in a number of countries. Among the predicting variables, a rise of temperature and rainfall have shown to be associated with the number of dengue cases [1]. While relatively less emphasized compared to the climatic factors, mass movement is particularly important during large-scale outbreaks. This article presents a case based on the available data from the 2019 outbreak in Bangladesh, where the dengue fever was initially concentrated in Dhaka, the capital city. Dhaka is one of the most crowded megacities in the world, with over 19 million people distributed over 453 square km (spatial density of 41,000/square km) [2]. It is a hub of all key administrative, educational, and industrial activities in Bangladesh. Hence, a considerable proportion of the Bangladeshi population prefers to live in the city for better income, quality education, and better facilities overall. The 2019 dengue outbreak in Dhaka was the most intense since the emergence of dengue outbreaks in late the 1990s in Bangladesh [3]. According to Directorate General of Health Services (DGHS), Bangladesh, a total of 100,201 confirmed dengue cases were admitted in hospitals between January and December 2019; 51,179 cases were reported in Dhaka city and 49,022 across the rest of Bangladesh [4]. This implies a 10-fold increase in hospitalized cases compared with the largest outbreak before 2019. Since the first major outbreak in 2000, all four serotypes (DEN-1-4) were reported in Dhaka city until 2003, a with higher prevalence of DEN-3 serotype. After a hiatus (2013-2016), DEN-3 serotype re-emerged in 2017, and this serotype has been reported to be the most frequently identified during the 2019 outbreak [5,6]. Anecdotal evidence from medical practitioners suggests that dengue patients manifested with a spectrum of atypical symptoms in the 2019 outbreak, which can be related to serodiversity of the viral strains. A recently published nationwide seroprevalence study (2014-2015) showed that 24% of participants had past history of dengue infection in Bangladesh [7]. Seropositivity of the infected individuals was largely confined to three big cities, namely Dhaka, Chittagong, and Khulna, indicating that circulation of dengue virus was not high in the semi-urban and rural areas of Bangladesh [7]. Notably, all major dengue outbreaks in Bangladesh showed a tendency to remain confined mostly in Dhaka city [7], and the 2019 outbreak showed the same trend PLOS NEGLECTED TROPICAL DISEASES

Detection of Anti-Nucleocapsid Antibody in COVID-19 Patients in Bangladesh Is not Correlated with Previous Dengue Infection

“…The percentage of patients in cohort 1 showing positive anti-dengue IgM and IgG was 6 and 81 percent, respectively, versus, 3 and 83 percent, respectively, in cohort 2 ( Table 2 ). The data confirm the high dengue IgG seroprevalence known for the dengue endemic populations of Bangladesh [ 10 , 13 ].…”

“…Scenario assessments in 2020 predicted the harsh impact of dengue infection and climate conditions on the strategic response to COVID-19 and management of clinical outcomes [ 11 , 12 ]. Surprisingly, the cumulative total of 1000 dengue fever cases in 2020 indicates a dramatic decline in hospitalized dengue virus infection from the previous year [ 13 , 14 ]. In the same period, the Bangladesh Institute for Epidemiology Disease Control and Research (IEDCR) reported 533,000 SARS-CoV-2 infections and over 8000 deaths from COVID-19, of which 70% were more than 50 years of age and were predominantly male [ 15 , 16 ].…”

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

“…This outbreak was caused by multiple viruses including a dominant DENV-2, along with DENV-1 and DENV-3 [ 8 , 10 , 12 , 13 ]. A subsequent outbreak in 2019 caused a surge of dengue patients 10 times as high as that of previous year, i.e., 100,201 confirmed cases, among which half of the patients occurred in Dhaka, while the remaining cases were found across the rest of Bangladesh [ 14 , 15 ]. Although DENV-3 was described as predominant in the unprecedented outbreak in 2019 [ 8 ], genotypes of the responsible DENV are not yet clarified.…”

Covid-19 and University Admission Exams: A Bangladesh Perspective

“…24 The ARIMA model itself was used to compare differences in dengue incidences in Bangladesh from two different time periods. 25 While other methods such as CUBIST 26 and artificial neural network 27 have been used in the past, we agreed that the ARIMA model would be the best for this study. This model has been widely and commonly used and has often found to be the most reliable with regards to accuracy in many previous studies.…”