Clinical profiles and hematologic patterns in Bangladesh's 2019 dengue outbreak

During the 2019 monsoon and post-monsoon seasons, Bangladesh experienced an unprecedented nationwide dengue outbreak, which, for the first time, spread to all sixty-four districts. This study aimed to analyze this outbreak's clinical and hematological features to understand the disease's progression and geographic variation in symptom presentation. We conducted a retrospective analysis of 1875 laboratory-confirmed dengue cases, including 432 children (23.0 %) and 1443 adults (77.0 %), aged 1–67 years. Clinical features were assessed with a focus on geographic variation, and hematologic indices, e.g., white blood cell (WBC) count and platelet count, were monitored throughout the illness. Fever was universally observed, serving as the cardinal symptom of dengue infection. Gastrointestinal complications were the second most frequent category of symptoms, with abdominal pain (55.9 %) and nausea and/or vomiting (47.5 %) being most common. Hemorrhagic symptoms were reported in approximately one-third of the participants. Additionally, 75.6 % and 60.1 % of participants experienced thrombocytopenia and leukocytopenia, respectively, with WBC and platelet counts sharply declining after symptom onset and gradually recovering by the second week. Participants from Dhaka reported significantly more gastrointestinal symptoms, e.g., abdominal pain and nausea/vomiting, compared to those from other districts, indicating geographic variation in clinical presentation. This study provides a comprehensive overview of the clinical and hematological profiles seen during the 2019 dengue outbreak in Bangladesh. It highlights the impact of geographic factors on clinical presentation and the need for customized management strategies to enhance dengue care and outbreak preparedness in similar settings.