Novel norovirus recombinants and GII.4 sub-lineages associated with outbreaks between 2006 and 2010 in Belgium

Abstract

BackgroundNoroviruses (NoVs) are an important cause of acute gastroenteritis in humans worldwide. To gain insight into the epidemiologic patterns of NoV outbreaks and to determine the genetic variation of NoVs strains circulating in Belgium, stool samples originating from patients infected with NoVs in foodborne outbreak investigations were analysed between December 2006 and December 2010.ResultsNoVs were found responsible of 11.8% of all suspected foodborne outbreaks reported in the last 4 years and the number of NoV outbreaks reported increased along the years representing more than 30% of all foodborne outbreaks in 2010. Genogroup II outbreaks largely predominated and represented more than 90% of all outbreaks. Phylogenetic analyses were performed with 63 NoV-positive samples for the partial polymerase (N = 45) and/or capsid gene (N = 35) sequences. For 12 samples, sequences covering the ORF1-ORF2 junction were obtained. A variety of genotypes was found among genogroups I and II; GII.4 was predominant followed in order of importance by GII.2, GII.7, GII.13, GI.4 and GI.7. In the study period, GII.4 NoVs variants 2006a, 2006b, 2007, 2008 and 2010 were identified. Moreover, phylogenetic analyses identified different recombinant NoV strains that were further characterised as intergenotype (GII.e/GII.4 2007, GII.e/GII.3 and GII.g/GII.1) and intersub-genotype (GII.4 2006b/GII.4 2007 and GII.4 2010/GII.4 2010b) recombinants.ConclusionsNoVs circulating in the last 4 years in Belgium showed remarkable genetic diversity either by small-scale mutations or genetic recombination. In this period, GII.4 2006b was successfully displaced by the GII.4 2010 subtype, and previously reported epidemic GII.b recombinants seemed to have been superseded by GII.e recombinants in 2009 and GII.g recombinants in 2010. This study showed that the emergence of novel GII.4 variants together with novel GII recombinants could lead to an explosion in NoV outbreaks, likewise to what was observed in 2008 and 2010. Among recombinants detected in this study, two hitherto unreported strains GII.e/GII.3 and GII.g/GII.1 were characterised. Surveillance will remain important to monitor contemporaneously circulating strains in order to adapt preventive and curative strategies.

Norovirus GII.17 Predominates in Selected Surface Water Sources in Kenya

“…After rotavirus, NoVs are the second most important cause of severe paediatric gastroenteritis (Glass et al 2009) and in the elderly NoV infection can be particularly severe, even resulting in death (Harris et al 2008;Tian et al 2014). Noroviruses are transmitted primarily via the faecal-oral route and contaminated food and water have been implicated in NoV-associated outbreaks of gastroenteritis (Mathijs et al 2011;Matthews et al 2012). …”

Of Mice and Microflora

“…There is evidence that MNVs may undergo homologous recombination events, creating viruses different from the parental strain. 80 Serologic crossreaction occurs for most of the strains, but MNV-1 may be distinct. Infection with one strain may not provide crossprotection against other strains.…”

Monitoring of norovirus and indicator microorganisms from agricultural products and environmental samples in Korea

“…토양 시료 토양은 10 g을 원심분리통에 넣고 100 mL의 1X Phosphate Buffered Saline (PBS, Biosesang, Sungnam, Korea) buffer을 사용 하여 희석하였으며 진탕배양기(IS-971R, Jeio tech, Seoul, Korea) (150 rpm, 2시간)에서 진탕배양하고, 원심분리(3,000 rpm, 10분)하 여 상층액만 취해 얻었다 (20)(21)(22). 얻어진 상층액은 농축과정 없 이, 상층액 1 mL은 위생지표세균(Coliform, E. coli)으로써 MSC 검사 시 사용하였으며, 나머지 상층액에 2 mL의 MNV-1을 1,000 pfu를 인위적으로 오염시킨 후 노로바이러스 검사에 사용하였다.…”

“…가축분변과 인체분변의 1 g을 1X 인산완충용액(Phosphate Buffered Saline) buffer 30 mL을 사용하여 상온에서 20분 동안 방치 하여 부유시킨 후 원심분리(3,000 rpm, 10분)하여 상등액만 취해 얻었다 (20)(21)(22). 여기서 원심분리 하지 않은 10 mL은 대장균군, 대 장균 검사에 사용하였고 원심분리 후 얻은 탈리용액 10 mL은 농 축과정 없이 MSC 검사에 사용하였으며, 나머지 약 10 mL 중 2 mL에 MNV-1을 1,000 pfu를 인위적으로 오염시킨 후 노로바이러 스 검사에 사용하였다.…”