Detection of norovirus in mouthwash samples from patients with acute gastroenteritis

Abstract

Background Norovirus infection is characteristically associated with vomiting which is known to contain a high concentration of viral particles. The oral cavity is therefore likely to become contaminated with norovirus during episodes of gastroenteritis. Objective To investigate the oral detection of norovirus in patients with norovirus gastroenteritis. Study design Faecal and oral mouthwash samples were collected in two separate settings. In the first setting, samples were collected repeatedly over a 3-week period from six family members experiencing a domestic outbreak of norovirus gastroenteritis. Secondly, samples were collected at a single time point following disease onset from 59 patients hospitalised with norovirus gastroenteritis. Norovirus detection in oral and faecal samples was undertaken by RT-PCR. Results In the family study, norovirus was detected in early morning mouthwash samples for 10–15 days following disease onset from each of six family members. In the hospital study, 14/59 hospitalised adults with norovirus infection had norovirus detected in mouthwashes (24%; 14–37% 95% C.I.). For the hospitalised adults, the detection of norovirus in mouthwash samples was associated with the presence of vomiting ( p = 0.1); and in those patients with norovirus infection whose mouthwash samples were collected within 24 h of the onset of vomiting, 59% (10/17) had norovirus detected. Conclusions Oral mouthwashes may provide an adjunct to faecal sampling to support the diagnosis of norovirus infection. The detection of norovirus in orally-derived material raises the possibility of oral-to-oral norovirus transmission, and that this potential for transmission may extend beyond the immediate symptomatic period.