The potential resurgence of Dengue Virus-4: A novel epidemiological pattern and altered symptomatology in Bangladesh

Abstract

Dengue fever is a viral illness spread by infected Aedes mosquitoes and
originates from one of five dengue virus serotypes (DENV 1-5). Recently,
the epidemiology of DENV has become a major concern worldwide. DENV
can be prevalent in both urban and semi-urban areas across the tropical and
sub-tropical continents, and over half of the global population is at risk of
contracting dengue fever. Bangladesh has experienced a significant rise in
reported cases of endemic dengue in recent years. Specifically, notable
increases were observed in 2018, 2019, 2021, 2022, and 2023. Alongside,
there was also a higher number of fatalities reported in these regimes.
During July 2025, there was a sharp increase in the prevalence of denguerelated infections and associated mortality. Specifically, a cumulative
number of 6,099 infected cases, with a corresponding fatality rate of 61.
This severe and potentially fatal case of dengue suggested the possible reemergence of DENV-4 in Bangladesh. Also, the resurgence and
predominance of the DENV-4 serotype this year may explain the
development of atypical symptomatology. Also, the rise in dengue cases in
the country could be associated with an alteration in the biting behaviors of
mosquitoes carrying the virus. However, the control of DENV infection
remains a significant challenge due to the lack of effective vaccines for all
serotypes of DENV. In light of the ongoing situation, the government is
faced with the necessity of implementing measures by the preventive
guidelines established by the Centers for Disease Control and Prevention
(CDC) and the World Health Organization (WHO).