Clinical and virological features of an aseptic meningitis outbreak in North-Eastern France, 2005

Abstract

Background

Enteroviruses (EVs) are considered as a major viral etiological cause of aseptic meningitis in children.

Objectives

We assessed the clinical and virological features of an aseptic meningitis outbreak in North-East of France, 2005.

Study design

Classical bacteriological analysis, Herpesviridae and EV PCR assays had been prospectively performed on cerebrospinal fluid (CSF) samples taken from 80 children hospitalized for aseptic meningitis. For each EV strain identified as etiological agent, a phylogenetic comparison of partial EV VP1 capsid protein coding gene was performed.

Results

The children older than 12 months (n = 75) presented a typical aseptic meningitis syndrome, whereas the children aged less than 1 year (n = 5) demonstrated only fever and hypotonia. Among the 80 studied children, EV was identified as the etiological cause of aseptic meningitis in 73 (91%) cases. Echovirus 30 (E30) was the most common isolated serotype (84% of 51 EV strains). VP1 phylogenetic analysis revealed that E30 strains were genetically closer to those isolated during 2000 aseptic meningitis outbreak comparatively to those identified during 2003 and 2006 non-epidemic years. Moreover, the genetic study demonstrated the co-circulation of four distinct lineages without any difference in temporal distribution or clinical features during the 2005 outbreak.

Conclusions

The present report demonstrates the co-circulation of distinct E30 lineages during the same aseptic meningitis outbreak season. This E30 genetic diversity may be a prerequisite for the emergence of new strains potentially responsible for further aseptic meningitis outbreaks.

Introduction

Aseptic meningitis is commonly defined as a syndrome characterized by acute onset of signs and symptoms of meningeal inflammation, cerebrospinal fluid (CSF) pleocytosis and the absence of microorganism on Gram stain and/or routine culture (Cherry, 2004). Aseptic meningitis is frequently caused by viral agents, particularly human enteroviruses (EVs) (King et al., 2007, Michos et al., 2007). Transmitted through the fecal oral route and potentially by respiratory route, EVs are the pathogen associated most commonly with acute meningitis worldwide and can cause sporadic cases, outbreaks and epidemics (Antona et al., 2007, Tseng et al., 2007). These epidemics typically occur during summer and fall in pediatric patients (Antona et al., 2007). Since the development of RT-PCR assays for their detection and their typing from the clinical samples, many aseptic meningitis outbreaks were described worldwide during the last few years (Mirand et al., 2007, Zhao et al., 2005). However, the virological mechanisms responsible for the emergence of EV neutrotropic epidemic strains remains poorly understood. During the 2005 summer season, enteroviruses were responsible for a major outbreak of acute aseptic meningitis in French children (Antona and Chomel, 2005, Mirand et al., 2006). The present study describes the clinical and virological features of this aseptic meningitis outbreak in North-East of France.