Acute gastroenteritis and enteric viruses in hospitalised children in southern Brazil: aetiology,seasonality and clinical outcomes

Viral acute gastroenteritis (AG) is a significant cause of hospitalisation inchildren younger than five years. Group A rotavirus (RVA) is responsible for 30% ofthese cases. Following the introduction of RVA immunisation in Brazil in 2006, adecreased circulation of this virus has been observed. However, AG remains animportant cause of hospitalisation of paediatric patients and only limited data areavailable regarding the role of other enteric viruses in these cases. We conducted aprospective study of paediatric patients hospitalised for AG. Stool samples werecollected to investigate human adenovirus (HAdV), RVA, norovirus (NoV) and astrovirus(AstV). NoV typing was performed by nucleotide sequencing and phylogenetic analysis.From the 225 samples tested, 60 (26%) were positive for at least one viral agent.HAdV, NoV, RVA and AstV were detected in 16%, 8%, 6% and 0% of the samples,respectively. Mixed infections were found in nine patients: HAdV/RVA (5), HAdV/NoV(3) and HAdV/NoV/RVA (1). The frequency of fever and lymphocytosis was significantlyhigher in virus-infected patients. Phylogenetic analysis of NoV indicated that all ofthese viruses belonged to genotype GII.4. The significant frequency of thesepathogens in patients with AG highlights the need to routinely implement laboratoryinvestigations.