Norwalk-Like Virus Sequences in Mineral Waters: One-Year Monitoring of Three Brands

Abstract

In a recent study, RNA with nucleotide sequeces specific for "Norwalk-like viruses" (NLV) was detected in 11 different brands of European mineral waters. To clarify this finding, a 1-year monitoring study was conducted. Samples of three European brands of mineral water without gas were monitored weekly by reverse transcriptase PCR using generic and genogroup-specific oligonucleotides. Additional analyses were performed to investigate a possible correlation between NLV sequence contamination and mineral water lot numbers, the long-term stability (persistence) of NLV sequences in mineral water, and the level of contamination. NLV sequences were detected in 53 of 159 samples analyzed (33%) and belonged entirely to genogroup II. Although all NLV strains identified were closely related, three mineral water brand-specific clusters could be identified for both primer systems by sequencing. Analyses of second samples from lots previously shown to be positive for NLV sequences gave corresponding results in 45 of 53 cases (85%) (within a six-pack). NLV persistence was tested by analyzing 10 positive samples after 6 and 12 months of storage in darkness at room temperature. After 6 months, all samples remained positive; after 12 months, 9 of 10 samples were still positive for NLV sequences. No NLV sequences could be detected by analysis of 0.1-liter aliquots of 53 samples shown to be positive by testing of 1-liter volumes. Based on this fact and a test sensitivity of approximately 10 viral units, levels of contamination in positive mineral water samples were estimated to be in the range of 10 to 100 genomic equivalents per liter.

Detection of caliciviruses associated with acute infantile gastroenteritis in Salvador, an urban center in Northeast Brazil

“…Our results agree with a previous report showing that region B primers are able to amplify more than 90% of the NoVs GI and GII (18).…”

“…The 139 fecal samples were tested by PCR using two different sets of primers: i) 289/290, which detects both NoVs (319-bp amplicons) and SaVs (331-bp amplicons) (17) and ii) a generic NoV PCR system based on the degenerate primers Mon 431/Mon 433 and Mon 432/Mon 434 of region B within 3'-end of ORF1 (RNA polymerase) (18). To avoid false-positive and -negative results, previously typed NoV GI/2a and NoV GII/4 strains and Milli-Q water were used as positive and negative controls, respectively.…”

Norovirus Infections in Symptomatic and Asymptomatic Food Handlers in Japan

“…This result suggests that the GII/4 strains are an important cause of both outbreaks and sporadic occurrences of gastroenteritis. Noroviruses can be transmitted by the fecal-oral route through person-to-person contact and by food-and waterborne infections (2,3,12). In Japan, oyster-associated gastroenteritis is a major problem, and it is not unusual to detect multiple norovirus genotypes in an oyster-associated outbreak (14).…”

Genotyping of gastroenteric viruses in hospitalised children: first report of norovirus GII.21 in Brazil

“…The semi-nested PCR for the RVA G and P genotyping were performed as previously described (Gentsch et al 1992, Das et al 1994, Leite et al 1996. NoV PCR was used to screen for NoV and was based on the degenerate primers Mon 431-434, which are specific to region B and are located within the 3'-end of open reading frame (ORF)1 (RNA polymerase) (Beuret et al 2002). The primers targeting the 3'-end of the major capsid gene (region D) were to molecularly characterise the virus (Vinjé et al 2004).…”