Dengue Virus Serotypes 1 and 2 Responsible for Major Dengue Outbreaks in Nepal: Clinical, Laboratory, and Epidemiological Features.

Shyam Prakash Dumre,Mahamoud Sama Cherif,Prakash Ghimire,In-Kyu Yoon,Sanjaya Kumar Shrestha,Renu Bhandari,Kesara Na-Bangchang,Chonticha Klungthong,Kenji Hirayama,Geeta Shakya,Stefan Fernandez

doi:10.4269/ajtmh.17-0221

Abstract

.Dengue virus (DENV) is expanding toward previously nonendemic areas. DENV has recently been introduced in Nepal with limited information. We report the clinical features and serotype distribution of DENV in Nepal during the 2010 outbreaks. A total of 1,215 clinical dengue cases at two major hospitals of central and western Nepal were investigated. Demographic, clinical, and laboratory parameters were recorded. Serum specimens were tested for DENV by IgM/IgG enzyme-linked immunosorbent assays (ELISAs) and reverse transcription polymerase chain reaction (RT-PCR). We confirmed DENV infection in 403 (33%) patients from 12 districts with an estimated case fatality rate of 1.5%. DENV infection was more common in adults (87%) and urban settings (74%). We detected all four serotypes but DENV-1 and -2 were mainly responsible for major outbreaks (92%). Overall, 60% of all DENV infections were secondary and 17% were severe dengue; both being more frequent among the DENV-2 infections. Rash, bleeding, abdominal pain, hepatomegaly, elevated liver enzymes, and thrombocytopenia were significantly more common in severe dengue compared with nonsevere infections. We also confirmed the expansion of dengue to hill urban areas (DENV-1 and -2), including the capital Kathmandu (altitude, 1,300 m) though > 90% cases were from southern plains. Differential clinical and laboratory features probably help in clinical decisions. Multiple serotypes circulation and elevated secondary infections pose potential risk of severe outbreaks and deaths in the future. Therefore, a country with recent dengue introduction, like Nepal, urgently requires a systematic surveillance and appropriate control measures in place to respond to any disastrous outbreaks.

Highlights

Global distribution of dengue virus (DENV) is constantly expanding and poses a significant health problem with 390 million dengue infections/year from more than 100 countries, 96 million of which are clinical.[1,2,3] These figures may still underestimate the actual dengue burden given the dramatic urbanization and inadequate dengue surveillance in tropical developing countries.[4]
The World Health Organization (WHO) South East Asia Region (SEAR) holds 50% of the global dengue burden and its member states are experiencing an upsurge in reported cases of dengue.[2,5]
Several studies on clinical features of DENV infections in both hospital patients and community cohorts indicate that clinical features are not uniform across the countries/continents, raising questions on their universal application in clinical settings.[7,8,9,10,11,12,13,14,15]

Summary

Introduction

Global distribution of dengue virus (DENV) is constantly expanding and poses a significant health problem with 390 million dengue infections/year from more than 100 countries, 96 million of which are clinical.[1,2,3] These figures may still underestimate the actual dengue burden given the dramatic urbanization and inadequate dengue surveillance in tropical developing countries.[4] The World Health Organization (WHO) South East Asia Region (SEAR) holds 50% of the global dengue burden and its member states are experiencing an upsurge in reported cases of dengue.[2,5]. DENV infections range from asymptomatic and undifferentiated fever to severe dengue manifestations. There are few reports describing clinical features of DENV infections in resource-poor areas

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