Inactivation and elimination of human enteric viruses by Pacific oysters

McLeod, Catherine; Hay, B.; Grant, C.; Greening, Gail E.; Day, D.

doi:10.1111/j.1365-2672.2009.04373.x

Cited by 49 publications

(40 citation statements)

References 48 publications

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“…The application of quantitative virus detection methods for MST of contaminated shellfish may complicate the picture further, as virus uptake, bioaccumulation, and persistence in shellfish were previously shown to be virus specific and to vary between seasons and shellfish species (2,28,33). The specific binding of NoV to certain carbohydrates in the digestive tract of oysters, mussels, and clams was demonstrated recently (28,46).…”

Section: Discussionmentioning

confidence: 99%

Viral Multiplex Quantitative PCR Assays for Tracking Sources of Fecal Contamination

Wolf

Hewitt

Greening

2010

Appl Environ Microbiol

158

112

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Human and animal fecal pollution of the environment presents a risk to human health because of the presence of pathogenic viruses and bacteria. To distinguish between human and animal sources of pollution, we designed specific real-time reverse transcription (RT)-PCR assays for human and animal enteric viruses, including norovirus genogroups I, II, and III; porcine adenovirus types 3 and 5; ovine adenovirus; atadenovirus; and human adenovirus species C and F, which are excreted by infected humans, pigs, cattle, sheep, deer, and goats, and for the detection of F؉ RNA bacteriophage genogroups I to IV, which are associated with human and animal wastes. The sensitivity of this viral toolbox (VTB) was tested against 10-fold dilution series of DNA plasmids that carry the target sequences of the respective viruses and was shown to detect at least 10 plasmid copies for each assay. A panel of human and animal enteric and respiratory viruses showed these assays to be highly sensitive and specific to their respective targets. The VTB was used to detect viruses in fecal and environmental samples, including raw sewage and biosolids from municipal sewage treatment plants, abattoir sewage, and fecally contaminated shellfish and river water, which were likely to contain animal or human viruses.It is important that sources of fecal pollution are rapidly and accurately identified so that environmental managers can develop strategies to eliminate the source of the pollution in an efficient and cost-effective manner. The identification of fecal sources also allows the potential risk to human health following the consumption of or exposure to contaminated food or water to be estimated. For this purpose, numerous fecal source tracking methods have been developed. Among these are library-dependent methods such as antibiotic resistance testing or molecular fingerprinting (e.g., terminal restriction length fragment polymorphism [T-RFLP] or ribotyping) and library-independent approaches, including the detection of human-specific bacteriophages by plaque assay (e.g., Bacteroides fragilis bacteriophages), the detection of certain chemicals associated with human and nonhuman wastes (e.g., caffeine, laundry brighteners, fecal sterols, and stanols), and the detection of specific genetic markers by PCR. The molecular detection of human and animal viruses and bacteriophages falls into the latter category. Each method has advantages and disadvantages depending on the circumstances and the questions at hand. To date, none has been proposed as a standard method (9,34,40,45).The detection and genotyping of Fϩ RNA bacteriophages have been widely used as a tool for microbial source tracking (MST) (5,8,17,18,31,44). Fϩ RNA bacteriophage genogroup I (GI) and GIV have been associated with animal contamination, and genogroups II and III indicate predominantly human fecal contamination or domestic sewage-associated in-

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Section: Discussionmentioning

confidence: 99%

Viral Multiplex Quantitative PCR Assays for Tracking Sources of Fecal Contamination

Wolf

Hewitt

Greening

2010

Appl Environ Microbiol

158

112

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“…Enteric viruses have previously been shown to be distributed throughout oyster tissues, such as in the gills and the digestive tract (33,54,55). To determine the proportion of viruses distributed within hemocytes compared to tissues, hemolymph was removed from whole oysters by direct draw with a pipette after shucking.…”

Section: Isolation Of Viruses From Hemocytesmentioning

confidence: 99%

“…A review of the research literature suggests that viruses differ in the ability to persist within shellfish (6,29,39,48,53). For example, McLeod et al (33) recently showed that HAV and HuNoV levels in oysters did not decrease significantly after a 23-h depuration period, while poliovirus (PV) levels declined substantially. Kingsley and Richards (29) demonstrated that HAV could be detected in oysters for as long as 6 weeks after exposure to virus-contaminated water, while Ueki et al (53) showed that feline calicivirus (FCV), a HuNoV surrogate, does not persist in oysters.…”

mentioning

confidence: 99%

Hemocytes Are Sites of Enteric Virus Persistence within Oysters

Provost

Dancho

Ozbay

et al. 2011

Appl Environ Microbiol

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The goal of this study was to determine how enteric viruses persist within shellfish tissues. Several lines of novel evidence show that phagocytic blood cells (hemocytes) of Eastern oysters (Crassostrea virginica) play an important role in the retention of virus particles. Our results demonstrated an association of virus contamination with hemocytes but not with hemolymph. Live oysters contaminated overnight with hepatitis A virus (HAV) and murine norovirus (MNV) had 56% and 80% of extractable virus associated with hemocytes, respectively. Transfer of HAV-contaminated hemocytes to naïve (virus-free) oysters resulted in naïve oyster meat testing HAV positive for up to 3 weeks. Acid tolerance of HAV, MNV, poliovirus (PV), and feline calicivirus (FCV) correlated with the ability of each virus to persist within oysters. Using reverse transcription-PCR (RT-PCR) to evaluate persistence of these viruses in oysters, we showed that HAV persisted the longest (>21 days) and was most acid resistant, MNV and PV were less tolerant of acidic pH, persisting for up to 12 days and 1 day, respectively, and FCV did not persist (<1 day) within oysters and was not acid tolerant. This suggests that the ability of a virus to tolerate the acidic conditions typical of phagolysosomal vesicles within hemocytes plays a role in determining virus persistence in shellfish. Evaluating oyster and hemocyte homogenates and live contaminated oysters as a prelude to developing improved viral RNA extraction methods, we found that viruses were extracted more expediently from hemocytes than from whole shellfish tissues and gave similar RT-PCR detection sensitivities.

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“…Provost et al (2011) (hematocytes) (acidic digestion) . feline calicivirus murine norovirus (Mcleod et al, 2009b;Nappier et al, 2008;Provost et al, 2011;Ueki et al, 2007).…”

Section: Real Time Rt-pcrmentioning

confidence: 99%

“…(Le Guyader et al, 2006;Mcleod et al, 2009aMcleod et al, , 2009bTian et al, 2006;Wang et al, 2008), (Maalouf et al, 2010;Nappier et al, 2008). Provost et al (2011) (hematocytes) (acidic digestion) .…”

Section: Real Time Rt-pcrmentioning

confidence: 99%