Enteric viruses in healthy children in Cameroon: viral load and genotyping of norovirus strains.

Data regarding prevalence of noroviruses (NoVs) among asymptomatic persons are scarce. The current study carried out on samples from Cameroon describes the asymptomatic shedding of NoVs and other enteric viruses in healthy children and in adults infected with HIV but lacking symptoms of gastroenteritis. Enteric viruses were common with a prevalence of 53.7% in the children, and 35.5% in the adult participants. Multiple enteric viruses (2-5 agents) were detected in fecal samples from 65% of the children, and co-infection with NoV was demonstrated in almost all cases of multiple infections. NoV viral loads in the healthy children were within disease causing range and significantly higher than those observed in the adults (P < 0.01). Sequencing and genotyping of NoV strains by phylogeny showed a marked diversity within two distinct genogroups, GI and GII, and strains clustered with genotypes GI.3, GII.17, GII.8, and GII.4. Genetic similarities to recent outbreak strains from other continents suggest a rapid circulation of NoVs that includes healthy children, who may constitute a reservoir for pathogenic NoVs.