Clinical, epidemiological and virological features of dengue virus infections in vietnamese patients presenting to primary care facilities with acute undifferentiated fever

Khoa T.D Thai,Hoang Lan Phuong,Tran Thi Thanh Nga,Phan Trong Giao,Le Quoc Hung,Nguyen Van Nam,Tran Quang Binh,Cameron Simmons,Jeremy Farrar,Tran Thinh Hien,H Rogier Van Doorn,Menno D De Jong,Peter J De Vries

doi:10.1016/j.jinf.2010.01.003

Abstract

SummaryObjectivesTo explore clinical and virological characteristics and describe the epidemiology of dengue in patients who presented with acute undifferentiated fever (AUF) at primary health centers (PHC) in Binh Thuan Province, Vietnam.MethodsA prospective observational study was conducted from 2001 to 2006 to study the aetiology in AUF patients. Demographic and clinical information was obtained, and dengue polymerase chain reaction (RT-PCR) and serology were performed on a random selection of patients.ResultsThree hundred fifty-one serologically confirmed dengue patients including 68 primary and 283 secondary infections were included in this study. In 25% (86/351) dengue virus (DENV) was detected by RT-PCR among which 32 DENV-1, 16 DENV-2, 1 DENV-3 and 37 DENV-4 were identified. The predominant dengue serotype varied by year with seasonal fluctuation: DENV-4 in 2001–2002, DENV-1 and DENV-2 from 2003 to 2006. Primary dengue was more common in children. Higher viraemia levels (P = 0.010) were found in primary infections compared to secondary infections. DENV-1 infected patients had higher viraemia levels than DENV-2 (P = 0.003) and DENV-4 (P < 0.001) infected patients. Clinical symptoms were often seen in adults. Few differences in clinical symptoms were found between primary and secondary infection and no significant differences in clinical symptoms between the serotypes were observed.ConclusionsOur data provide insight in the epidemiology, clinical profile and virological features of mild symptomatic dengue patients who presented to PHC with AUF in Vietnam.

Highlights

Mosquito-borne flavivirus infections such as dengue have rapidly spread and are one of the most important infectious diseases in the world, in terms of morbidity and mortality.[1,2] It is a public health problem with growing global incidence and geographic distribution to almost all tropical and subtropical regions, and with a transition from epidemic to endemic transmission intensity
Dengue is caused by an infection with a dengue virus (DENV) and transmitted primarily by Aedes spp. mosquito vectors.[4]
Binh Thuan Province is located along the south-eastern coast of Vietnam, 150 km northeast of Ho Chi Minh City

Summary

Introduction

Mosquito-borne flavivirus infections such as dengue have rapidly spread and are one of the most important infectious diseases in the world, in terms of morbidity and mortality.[1,2] It is a public health problem with growing global incidence and geographic distribution to almost all tropical and subtropical regions, and with a transition from epidemic to endemic transmission intensity. Recent estimates indicate that over 3.5 billion people (w55%) of the world population are living in areas at risk for dengue.[3]. The mechanisms for the variable clinical course are not completely elucidated, but interactions between virus and host immunity and hyperendemicity of multiple serotypes are believed to play an important role in determining the outcome of disease.[7]

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