Emergence of Genotype I of Dengue Virus Serotype 3 during a Severe Dengue Epidemic in Sri Lanka in 2017

Abstract

During the 2017 outbreak of severe dengue in Sri Lanka, dengue virus (DENV) serotypes 2, 3 and 4 were co-circulating. Based on our previous study on the 295 patients from the National Hospital Kandy in Sri Lanka between March 2017-January 2018, the dominant infecting serotype was DENV-2. Here, we aimed to characterize the DENV-3 strains from non-severe and severe dengue patients from our previous study population. Patients' clinical records and previous laboratory tests including dengue-specific nonstructural protein 1 antigen rapid test, IgM-capture and IgG enzymelinked immunosorbent assays, were analyzed together with the present results of real-time reverse transcription polymerase chain reaction, and next-generation sequencing of DENV-3. Based on complete genome analysis, DENV-3 isolates belonged to two different clades of genotype I and were genetically close to the strains from Indonesia, China, Singapore, Malaysia and Australia. There were sixteen amino acid changes among DENV-3 isolates, and the greater number of changes was found in nonstructural than structural proteins. The emergence of DENV-3 genotype I was noted for the first time in Sri Lanka. Continuous monitoring of this newly emerged genotype and other DENV serotypes/genotypes are needed to determine their effects on future outbreaks and to understand the molecular epidemiology of dengue.

Identifying the strains of dengue circulating in the western province of Sri Lanka during 2019–2022

“…In numerous countries, the occurrence of serotype switches in circulating dengue viruses has been linked to severe epidemics, particularly when the population is exposed to a new serotype. It is important to note that host immunity developed against one dengue serotype provides only partial protection against other serotypes [ 12 , 23 , 24 ]. In fact, the presence of heterotypic antibodies may even exacerbate the inflammatory response when a person is infected with a different serotype.…”