Background: Rotavirus infection is thought to be confined to the intestine. Reports of rotavirus RNA in the cerebral spinal fluid and serum of children infected with rotavirus suggest the possibility that rotavirus escapes the intestine into the circulatory system. We assessed whether rotavirus antigen, RNA, or both, were present in serum samples from immunocompetent rotavirus-infected children and animals.

Methods: We obtained sera from immunocompetent mice, rats, rabbits, and calves 1-10 days after inoculation with rotavirus or matched vehicle. We obtained sera retrospectively from immunocompetent children diagnosed with rotavirus diarrhoea (n=33), healthy children (n=6) and adults (n=12), children convalescing from rotavirus (n=6), and children with non-rotavirus diarrhoea (n=11). Samples were analysed for the presence of rotavirus antigen or RNA by EIA or RT-PCR, respectively.

Findings: Rotavirus antigen was present in sera from rotavirus-infected animals, but not in sera from control animals. Infectious rotavirus or rotavirus RNA was detected in sera of mice and calves, respectively. Antigen was present in 22 of 33 serum samples from children with confirmed rotavirus infection but in none of 35 samples from controls. Detection of serum antigen was inversely related to the number of days between symptom onset and sample collection, and directly related to stool antigen concentration. Rotavirus RNA was detected by RT-PCR in three of six rotavirus-positive sera.

Interpretation: Rotavirus can escape the gastrointestinal tract in children, resulting in antigenaemia and possible viraemia. This finding is important for the understanding of the pathogenesis, immunology, and clinical manifestations of rotavirus infection.