Aseptic meningitis outbreak associated with echovirus 4 in Northern Europe in 2013-2014

Area of Science:

• Virology
• Epidemiology
• Infectious Diseases

Background:

• Picornaviruses, including enteroviruses and parechoviruses, are RNA viruses transmitted via fecal-oral and respiratory routes.
• These viruses can cause aseptic meningitis by accessing the central nervous system (CNS).
• Echovirus 4 (E4) is infrequently detected in Finland.

Purpose of the Study:

• To investigate a detected cluster of echovirus 4 (E4) infections in young adults and adolescents in Finland during 2013-14.
• To determine the genetic relationship of the E4 strains causing infections in Northern and Central Europe during 2013-2014.

Main Methods:

• Diagnostic screening of entero- and parechovirus types.
• Collaboration with Northern and Central European laboratories for E4 sequence and data collection.
• Phylogenetic analysis of E4 virus sequences.

Main Results:

• A cluster of echovirus 4 (E4) infections was identified in Finland in 2013-14, primarily affecting young adults and adolescents.
• E4 infections were subsequently reported in Sweden, Norway, Denmark, Iceland, and Germany during 2013-2014.
• Phylogenetic analysis demonstrated that the E4 strains detected in these countries formed a single, distinct lineage.
• This 2013-2014 E4 lineage contrasted with earlier circulating E4 strains and those found elsewhere in Europe, which formed multiple independent clusters.

Conclusions:

• Echovirus 4 (E4) caused a distinct outbreak of CNS infections in Northern and Central Europe between 2013 and 2014.
• The identified E4 strains represent a novel, single lineage that emerged and spread across the region.
• This finding highlights the importance of ongoing viral surveillance and molecular epidemiology in understanding emerging infectious disease threats.