Local epidemiological surveillance of Norovirus infections in children hospitalized for gastroenteritis

Objective. Aim of this study was to determine the prevalence and distribution of the Norovirus (NoVs) infections, from October 2007 to April 2008, in children hospitalized for gastroenteritis. Materials and methods. From October 2007 to April 2008 faecal specimens were obtained from 220 infants and children (130 males, 90 males) of whom 58 under 1, 60 between 1 and 2, 28 between 2 and 3, 74 between 3 and 12 years old, admitted for gastroenteritis to the Department of Paediatrics at the Campo di Marte’s Hospital in Lucca, Italy. All the specimens were examined both for the presence of bacteria (Salmonella spp, Shigella spp, Campylobacter spp, Yersinia spp, Aeromonas spp and enteropathogenic E. coli) and for the presence of rotaviruses (HRVs) and adenoviruses (AdVs). Sixty-eight frozen stool samples negative for bacteria and viruses were examined for NoVs. HRVs and AdVs were detected by the immunochromatographic test RIDAQUICK Rotavirus/Adenovirus Combi test (R-Biopharm, Germany). NoVs detection was carried out by the enzyme immunoassay RIDASCREEN Norovirus 3rd Generation EIA (R-Biopharm, Germany). In the RIDASCREEN Norovirus test, specific monoclonal antibodies against antigens of several different genotypes are used in a sandwich type method. In a validation study of the RIDASCREEN Norovirus ELISA 3rd Generation at the Institute of Virology of the University of Dresden, the test correlation with the RT PCR showed the following performance, sensitivity (83.0%), specificity (100.0%), PPV (100.0%), NPV (83.0%). Results. HRVs were detected in 41.8% (89/220), AdVs in 4.1% (9/220) and Enteropathogenic bacteria were detected only in 7 (3.2%) patient. NoVs were detected in 18 of 68 studied cases (26.5%). Eighty-three of the NoVs and 49% of the HRVs infections occurred in children up two years old. Conclusions. The present results point out the importance of NoVs infections in childhood hospitalization, mainly in the first two years of life.The study shows the need to implement norovirus ELISA detection assays for clinical diagnosis and for planning an active surveillance among paediatric cases requiring hospitalization due to gastroenteritis for the development of effective preventive measures.