Molecular study of 2019 dengue fever outbreaks in Nepal

Abstract Background Dengue cases have been continuously reported in Nepal, including some large outbreaks, since its first introduction in 2004. The disease is now expanding towards newer locations above 1400 m high, especially the country's capital city, Kathmandu. In 2019, >14,000 dengue cases including six deaths were reported. This study was aimed at the detection and molecular characterization of dengue virus (DENV) in dengue patients. Methods A total of 451 patients were enrolled in this study. Demographic, clinical and laboratory information was collected from dengue patients. Dengue infection was confirmed by antibody/antigen detection assays followed by RT-PCR analysis. Results The DENV patients showed fever, body ache, headache, myalgia, retro-orbital pain and arthralgia. The platelets were decreased, serum liver enzymes were increased and leucopenia was seen. Out of 195 patients, 111 (57.0%) were positive for DENV RNA by consensus PCR. We found DENV-2, 70 (63.1%) as the predominant serotype responsible for the 2019 outbreak, while DENV-3 was detected in two patients. Conclusion Our findings suggest that DENV-2 was the major serotype causing the 2019 massive outbreak in Nepal. This information will help in disease control programs to understand the molecular epidemiology and its changing trend.