Wombling surplus diagnostic nucleic acid for novel pathogenesis and genetic epidemiology of viral infections

Nottingham University Hospitals Trust receives circa 13 000 samples for diagnosis of respiratory and neurological viruses per annum, however positive results are achieved in approximately 50 % of respiratory and 20 % of neurological investigations. We therefore aimed to retrospectively extend the diagnostic spectrum for these samples by applying a battery of degenerate PCR assays to surplus diagnostic nucleic acids.218 previously negative respiratory specimens collected in 2016 from children under 5 years old, identified positivity of 11 % for Human Bocavirus, 5 % for Human Enteroviruses (including 3 cases of Enterovirus D68), 4 % for Human Coronaviruses and one individual positive for Trichodysplasia Spinulosa Polyomavirus. Complementary investigation of 1730 previously negative specimens from children and adults with neurological symptoms yielded positive results for Hepatitis E, BK Polyomavirus and Astroviruses in addition to Entero- and Parechoviruses apparently missed by standard diagnostic assays. Our extensive archive further allowed us to investigate relatively rare viral infections in significant numbers. Therefore we also studied the genetic and clinical epidemiology of the human Rubulavirus pathogens Parainfluenza 2 and 4 in 121 and 237 patients respectively between 2013 and 2017. This indicated co-circulation of three clusters of Parainfluenza 4 in Nottingham with greater presentation of subtype 4b than 4a and 2 clades of Parainfluenza 2. 5 fatalities were recorded in the Parainfluenza 2 cohort. In summary, surplus nucleic acid from viral diagnostic laboratories represents a valuable resource for both service development and clinical research. Coronavirus, Bocavirus and Enterovirus testing have since been implemented in the routine diagnostic panel for respiratory investigations.