Genetic Diversity of Norovirus Infections, Coinfections, and Undernutrition in Children From Brazilian Semiarid Region

Abstract

Background and objective: Norovirus (NoV) infections are known to have high-morbidity and mortality rates and are a major health problem globally. The impact of NoV on child development is, however, poorly understood. We evaluated the distribution of NoV genotypes in children from a low-income Brazilian semiarid region, in relation with their clinical symptoms, nutritional status, and co-pathogens.

Methods: The test population included children aged 2 to 36 months from 6 cities of the Brazilian semiarid region. Fecal samples were collected from each child, along with the information regarding their socioeconomic/clinical conditions using a standardized questionnaire. Detection and quantification of NoV were performed by reverse-transcription quantitative polymerase chain reaction, followed by molecular and phylogenetic analyses.

Results: The NoV detection rate was 45.2%. Presence of NoV was associated with lower z scores for weight-for-age (P = 0.03), weight-for-height (P = 0.03), and body mass index-for-age (P = 0.03). NoV infection was associated with more frequent respiratory illnesses (P < 0.01). GII.P7 (polymerase) and GII.3 (capsid) were the most frequent NoV genotypes. Analysis of the open reading frame (ORF)1-2 junction identified recombinant NoV strains in 80% of the sequenced samples. Enteroaggregative Escherichia coli coinfection was the major predictor for diarrhea in NoV-positive samples (P < 0.02). Moreover, Shigella spp was also associated with NoV-positive diagnosis (P = 0.02).

Conclusions: This study highlights the genetic variability of NoV and, associated co-infections and undernutrition in infants from low-income Brazilian semiarid region.