Surveillance of Environmental Contamination and Human Exposure opf Noroviruses in Luxembourg - SENSORLUX
Coordinating Institution:
Laboratoire National de Santé
Contracting Partner(s):
CRP Gabriel Lippmann ,
CRP-Santé ,
Direction de la Santé, Luxembourg
Other Partner(s):
RIVM Bilthoven (NL) ,
COST Network ,
Laboratoires Réunis, Junglinster (L)
From: 01/01/2008
To: 31/03/2010
Budget: 499,171.00€
Contact(s):
Mossong Joel
Summary
Noroviruses (NoVs) are one of the leading causes for infectious gastroenteritis and the most common foodborne virus in developed countries. Patients with so-called “stomach flu” usually develop acute, self-limiting gastro-enteritis, but fragile persons, like infants, the elderly or immuno-depressed persons, are at increased risk of complications. The objective of our project was to develop a molecular surveillance program in Luxembourg for NoV infections in humans and to monitor environmental, water and food contamination with NoVs.
During 2009, 201 human stool samples were submitted for norovirus analysis of which 90 were positive for Nov genogroup II whereas no samples positive for genogroup I. Laboratory confirmed outbreaks occurred in 8 different nursing homes, one crèche and one geriatric unit at a hospital. The last case of the 08/09 winter season was detected in May. NoV monitoring in the environment until June 2009 in three major wastewater treatment plants (Beggen, Schifflange and Petange). A total of 82 samples have been collected.
NoV GGII were detected in 80 samples out of 82 (97%) while 36 were positive for GGI (44%). The two samples that were negative for NoV (both GGI and II). No significant difference of NoV concentration was observed regarding to the sample location. Therefore, the results were combined and analysed in function of time. The highest concentration of NoV GGI was observed in January with an average of 2.9 log PDU/100ml while the lowest concentration was observed in April-June with 0.2 log PDU/100ml.
The highest concentration of NoV GGII was observed in February with an average of 5.2 log PDU/100ml while the lowest concentration was observed in April-June with 3.4 log PDU/100ml. A comparison of NoV diversity found in clinical and environmental samples is in progress. Region A (RdRp, ORF1) and/or Region C (capsid, ORF2) sequences were obtained from 159 samples (97 LNS and 62 Laboratoires Réunies) collected from humans between October 2008 and June 2009.
Seven different genotypes were found (GI.2, GII.2, GII.3, GII.4, GII.6, GII.12 and GII.14) and the large majority of strains obtained from NoV epidemics as well as through routine surveillance belonged to GII.4 (~80%). GII.4 could be further subdivided in several distinct lineages indicating that multiple variants of NoV were co-circulating in humans during the study period. NoV sequences identified in sewage water largely reflected the circulation of NoV variants in humans, but the highest diversity was identified among strains from routine surveillance in humans.