Distribution of Dengue Virus Serotypes during the COVID 19 Pandemic in Sri Lanka

Abstract

Background: Dengue virus (DENV) infection is highly endemic in Sri Lanka with frequent epidemics. Knowledge on DENV serotype distribution will provide important information on impending epidemics. Understanding the disease burden of DENV infection during COVID-19 pandemic is highly important. Objective: To analyze the incidence of DENV infection and serotype distribution among clinically suspected patients with DENV infection during COVID-19 pandemic in Sri Lanka. Study design: This retrospective study analyzed 1796 plasma samples from patients with clinically suspected DENV infection received at Medical Research Institute (MRI), for testing of DENV RNA, from May 2019 to April 2021. Detection of viraemia and serotypes was performed using a commercially-validated serotyping real time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). Demographic and clinical details were recruited from accompanying request forms. Results were analyzed using descriptive statistics and chi square testing. Results: Of the samples 69.2% (n=1243) became positive for DENV RNA with 55.34% (n=688) belonging to patients under 16 years and 20.99% (n=261) to patients with severe infection. The vireamic rate ranged from 31.9% to 80.12% during different quarters of the study period. DENV-2 was detected in 40.2% (n=500) followed by DENV-3(37.97%, n=472) and DENV-1(15.44%, n=192) while co-infection with two different serotypes was observed in 5.79% (n=72). DENV- 3(47.5%, n=124) and DENV-2(39.46%, n=103) exhibited high percentage of positivity among patients with severe infection. Conclusions: Incidence of Dengue virus infection in Sri Lanka showed a noticeable decrease during study period. DENV-2 and DENV-3 exhibited dominance with re-emergence of DENV-1 and co- infection with multiple serotypes. DENV-2 and DENV-3 were detected with severe infection predominantly.