Presence of human non-polio enterovirus and parechovirus genotypes in an Amsterdam hospital in 2007 to 2011 compared to national and international published surveillance data: a comprehensive review

Enteroviruses (EV) and human parechoviruses (HPeV) are endemic worldwide. These infections are a constant cause of hospitalisation and severe disease, predominantly in young children and infants. Coordinated monitoring and surveillance are crucial to control these infections. We have monitored EV and HPeV epidemiology in Amsterdam from 2007 to 2011 with real-time RT-PCR and direct genotyping, facilitating highly sensitive surveillance. Moreover, we conducted a literature survey of existing surveillance data for comparison. Only 14 studies were identified. While HPeV1 was most frequently detected in Amsterdam, EV-B viruses dominated nationally and internationally. Furthermore, the top 10 strains detected differed yearly and per study. However, detection and typing methods were too varied to allow direct comparison and comprehension of the worldwide distribution and circulation patterns of the different genotypes. This limited a direct response to anticipate peaks. Uniform European monitoring programmes are essential to aid prediction of outbreaks and disease management.

Continued seasonal circulation of enterovirus D68 in the Netherlands, 2011-2014

Enterovirus D68 (EV-D68) continued to circulate in a seasonal pattern in the Netherlands, after the outbreak in 2010. Outpatient EV-D68 cases, mainly in the under 20 and 50–59 years age groups, presented with relatively mild respiratory disease. Hospital-based enterovirus surveillance identified more severe cases, mainly in children under 10 years of age. Dutch partial VP1 genomic region sequences from 2012 through 2014 were distributed over three sublineages similar to EV-D68 from the outbreak in the US in 2014.

Recombination dynamics of human parechoviruses: investigation of type-specific differences in frequency and epidemiological correlates

Human parechoviruses (HPeVs) are highly prevalent RNA viruses classified in the family Picornaviridae. Several antigenically distinct types circulate in human populations worldwide, whilst recombination additionally contributes to the genetic heterogeneity of the virus. To investigate factors influencing the likelihood of recombination and to compare its dynamics among types, 154 variants collected from four widely geographically separated referral centres (UK, The Netherlands, Thailand and Brazil) were typed by VP3/VP1 amplification/sequencing with recombination groups assigned by analysis of 3Dpol sequences. HPeV1B and HPeV3 were the most frequently detected types in each referral region, but with marked geographical differences in the frequencies of different recombinant forms (RFs) of types 1B, 5 and 6. HPeV1B showed more frequent recombination than HPeV3, in terms both of evolutionary divergence and of temporal/geographical indicators of population separation. HPeV1 variants showing between 10 and 20% divergence in VP3/VP1 almost invariably fell into different recombination groups, compared with only one-third of similarly divergent HPeV3 variants. Substitution rates calculated by beast in the VP3/VP1 region of HPeV1 and HPeV3 allowed half-lives of the RFs of 4 and 20 years, respectively, to be calculated, estimates fitting closely with their observed lifespans based on population sampling. The variability in recombination dynamics between HPeV1B and HPeV3 offers an intriguing link with their markedly different seasonal patterns of transmission, age distributions of infection and clinical outcomes. Future investigation of the epidemiological and biological opportunities and constraints on intertypic recombination will provide more information about its influence on the longer term evolution and pathogenicity of parechoviruses.