Abstract
Objectives: Limited information is available on the distribution of dengue virus (DENV) serotypes and genotypes in Borneo, particularly, in Sabah, because most studies have focused on Peninsular Malaysia. This study aimed to investigate the serologic and molecular epidemiologic characteristics of DENV in patients from Sabah. Methods: Serum samples were collected from febrile patients in Kota Kinabalu and Lahad Datu between 2019 and 2020 at the Kota Kinabalu Public Health Laboratory. We performed virus isolation, serological testing, viremia quantification, and complete genome sequencing. Results: Of 188 serum samples, 89 tested positive for DENV by quantitative reverse transcription-polymerase chain reaction: 20 DENV-1, 46 DENV-2, 20 DENV-3, and 1 DENV-4. A total of 38 viruses were successfully isolated. The isolates belonged to DENV-1 (genotypes I and IV), DENV-2 (cosmopolitan genotype) and DENV-3 (genotypes I and III). The phylogenetic analysis revealed close relationships with strains from Malaysia, Indonesia, and the Philippines. DENV-2 was the predominant serotype, whereas the highest viremia levels were observed in patients infected with DENV-3. Conclusions: To the best of our knowledge, this study provides the first detailed phylogenetic and complete genome analysis of DENV in Sabah. Continued molecular surveillance is essential to enhance our understanding of dengue transmission and support effective control strategies.