The peculiar story of the ubiquitous Enterovirus and its enigmatic companion, the Parechovirus

Enteroviruses (EVs) and parechoviruses (PeVs) are highly prevalent viruses worldwide. Together, these groups contain over 120 different virus types, that cause a wide spectrum of disease in humans. Several types - such as poliovirus, EV-A71, EV-D68 and PeV-A3 – have caused large outbreaks of severe disease over the past decades. However, most EV and PeV infections remain subclinical. The many EV and PeV types show complicated circulation patterns that change over time and differ per geographic region. As a result, our knowledge on the epidemiology of these large groups of viruses is limited. The aim of this thesis is to increase our insight in the epidemiology of EVs and PeVs by studies on their prevalence, seroprevalence and molecular epidemiology in several populations.