Monitoring telehealth vomiting calls as a potential public health early warning system for seasonal norovirus activity in Ontario, Canada

Abstract

Norovirus is a predominant cause of infectious gastroenteritis in countries worldwide [1-5]. It accounts for approximately 50% of acute gastroenteritis (AGE) and >90% of viral gastroenteritis outbreaks [6, 7]. The incubation period ranges between 10 and 48 h and illness duration is generally 1-3 days with self-limiting symptoms; however, this duration is often longer (e.g. 4-6 days) in vulnerable populations such as hospital patients or young children [2, 8]. Symptomatic infection of norovirus presents as acute vomiting, diarrhoea, abdominal cramps and nausea, with severe vomiting and diarrhoea (non-bloody) being most common [2, 5, 9].

Keywords: Norwalk agent and related viruses; Surveillance system; gastroenteritis; surveillance.

Fig. 1.

Weekly telehealth vomiting calls (‘vomiting’ and ‘vomiting and diarrhoea’ chief complaints) and laboratory-positive norovirus submissions, 17 June 2011–30 September 2014.

Fig. 2.

Weekly telehealth vomiting calls adjusted to remove long-term trend, with the ‘baseline’ mean number of calls and standard deviations marked, 19 June 2011–29 August 2015.