The Application of New Molecular Methods in the Investigation of a Waterborne Outbreak of Norovirus in Denmark, 2012

Abstract

In December 2012, an outbreak of acute gastrointestinal illness occurred in a geographical distinct area in Denmark covering 368 households. A combined microbiological, epidemiological and environmental investigation was initiated to understand the outbreak magnitude, pathogen(s) and vehicle in order to control the outbreak. Norovirus GII.4 New Orleans 2009 variant was detected in 15 of 17 individual stool samples from 14 households. Norovirus genomic material from water samples was detected and quantified and sequencing of longer parts of the viral capsid region (>1000 nt) were applied to patient and water samples. All five purposely selected water samples tested positive for norovirus GII in levels up to 1.8×104 genomic units per 200 ml. Identical norovirus sequences were found in all 5 sequenced stool samples and 1 sequenced water sample, a second sequenced water sample showed 1 nt (<0.1%) difference. In a cohort study, including 256 participants, cases were defined as residents of the area experiencing diarrhoea or vomiting onset on 12–14 December 2012. We found an attack rate of 51%. Being a case was associated with drinking tap-water on 12–13 December (relative risk = 6.0, 95%CI: 1.6–22) and a dose-response relation for the mean glasses of tap-water consumed was observed. Environmental investigations suggested contamination from a sewage pipe to the drinking water due to fall in pressure during water supply system renovations. The combined microbiological, epidemiological and environmental investigations strongly indicates the outbreak was caused by norovirus contamination of the water supply system.

Molecular epidemiology of human adenovirus infections in Denmark, 2011–2016

“…Feces, eye or respiratory samples received at the Statens Serum Institut for primary (real time PCR targeting F/non-F species in feces or non-feces, respectively) differential diagnosis of HAdV infections [18,19] between January 2011 and September 2016 were retrospectively selected for this study. Type of sample material, demographic information (age and sex) and geographical location were available from most samples.…”

Monitoring human enteric viruses in wastewater and relevance to infections encountered in the clinical setting: a one-year experiment in central France, 2014 to 2015

“…Environmental surveillance of specimens contaminated by human faeces is used to monitor enteric virus transmission in the population. It is crucial for monitoring water quality, because enteric viruses excreted in the environment are a potential source of human contamination and community-wide outbreaks [ 1 - 3 ]. The World Health Organization (WHO) added environmental surveillance of poliovirus to that of acute flaccid paralysis in the strategy plan of the Global Polio Eradication Initiative [ 4 ].…”

Separate norovirus outbreaks linked to one source of imported frozen raspberries by molecular analysis, Denmark, 2010–2011

“…in oysters [4], berries [10], lettuce [5] and drinking water [15]. For the outbreaks described here, norovirus of different types were detected in raspberries from bags related to five of the six initial outbreaks, showing that the berries were contaminated.…”

“…Samples positive for norovirus were genotyped by reverse transcriptase (RT)-PCR and sequence analysis of partial capsid and/or polymerase genes [15,16].…”