Parechovirus is a viral infection predominantly affecting those under one year of age. Infection usually manifests as mild respiratory or mild gastrointestinal symptoms. However, infection can lead to severe illness including meningitis, myocarditis and encephalitis, particularly in infants. Parechoviruses are commonly spread and more than 95% of cases are infected early in life, within two to five years of age.
Laboratory detections of parechovirus infections reported to ECOSS by month have been investigated in Scotland for the period January 2012 to May 2016 (Figure 1). Peaks in parechovirus activity (as indicated by a rise in ECOSS reports) have been described in Scotland previously and occur every two years, with the number of laboratory detections in 2016 (up to end May) showing a similar rise to that seen in the previous peak years, 2012 and 2014. Levels of parechovirus in 2013 and 2015 are much lower.
The age profile of parechovirus detections are shown in Figure 2. The majority of laboratory detections were in the under five age group, with around two-thirds (68%) of detections being in those under one. Only a small number of laboratory detections (5.3%) were in individuals over five years.
Parechovirus was detected in alimentary samples (~ 40% samples in Scotland), respiratory samples (~25% samples) and sterile site, principally CSF, samples (~30% samples). Looking at samples from sterile sites as a proxy for severe invasive disease, the main age group developing severe illness was those under one.
In light of the increase in parechovirus detections described, NHS boards and clinicians should be aware of parechovirus as a possible cause of meningitis and encephalitis, especially in infants, and request appropriate testing. Similarly, microbiologists should be aware of the current increase in incidence of parechovirus and recommend testing where appropriate, and refer samples to their regional laboratory if testing is not available locally.