Estimating risk associated with human norovirus and hepatitis A virus in fresh Australian leafy greens and berries at retail
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
Authors: Torok, Valeria A.; Hodgson, Kate R.; Jolley, Jessica; Turnbull, Alison; McLeod, Catherine
The apparent international rise in foodborne virus outbreaks attributed to fresh produce and the increasing importance of fresh produce in the Australian diet has led to the requirement to gather information to inform the development of risk management strategies. A prevalence survey for norovirus (NoV) and hepatitis A virus (HAV) in fresh Australian produce (leafy greens, strawberries and blueberries) at retail was undertaken during 2013-2014 and data used to develop a risk profile. The prevalence of HAV in berries and leafy greens was estimated to be < 2%, with no virus detected in produce during the yearlong survey. The prevalence of NoV in fresh strawberries and blueberries was also estimated to be < 2% with no virus detected in berries, whilst for leafy greens the NoV prevalence was 2.2%. Prevalence of a bacterial hygiene indicator, Escherichia coli, was also investigated and found to range from < 1% in berries to 10.7% in leafy greens. None of the NoV positive leafy green samples tested positive for E. coli, indicating it is a poor indicator for viral risk. The risk was evaluated using standard codex procedures and the Risk Ranger tool. Taking all data into account, including the hazard dose and severity, probability of exposure, probability of infective dose and available epidemiological data, the risk of HAV and NoV foodborne illness associated with fresh Australian berries (strawberries and blueberries) sold as packaged product was deemed to be low. The risk of foodborne illness from HAV associated with leafy greens was also deemed to be low, but higher than that for fresh berries, due mainly to the potential for recontamination post-processing if sold loose. The risk of foodborne illness from NoV associated with leafy greens was deemed to be low/moderate. Despite the prevalence of NoV in leafy greens being low and the inability to discriminate between infective and non-infective virus using PCR based methodologies, the fact that NoV was detected resulted in a higher risk associated with this pathogen-product pairing; compounded by the higher prevalence of NoV within the community compared to HAV, and the potential for leafy greens to become contaminated following processing if sold loose.
Immunity to Vaccine-preventable Viral Infections in Australians Being Evaluated for Liver Transplantation
Authors: Gardiner, Astrid; Liu, Ken; Bonnichsen, Mark; Joshi, Vikram; Davis, Rebecca J.; Strasser, Simone, I
Background. Vaccine-preventable viral infections are associated with increased risk of morbidity and mortality in immunocompromised patients. Current guidelines recommend routine screening and vaccination of all patients before solid organ transplantation. We studied rates of immunity against vaccine-preventable viruses in liver transplantation (LT) recipients. Methods. We retrospectively studied consecutive adult patients who underwent first deceased donor LT at a single center between August 2008 and October 2017. Viruses studied were hepatitis A (HAV), hepatitis B (HBV), varicella zoster virus (VZV), measles, and mumps. Hepatitis B surface antibody (anti-HBs) Results. Five hundred and fifty-five patients underwent LT (72.4% male; median age, 55.0 y). Percentages of patients who lacked immunity to vaccine-preventable infections were HAV (31.8%), HBV (63.8%), measles (1.4%), mumps (6.6%), and VZV (3.8%). Age was positively associated with immunity (from either past exposure or vaccination) against most viruses, including HAV, measles, mumps, and VZV (P < 0.05 for all). In contrast, older age was marginally associated with anti-HBs <10 IU/mL (P = 0.046). No significant changes in immunity rates were observed during the study period. Conclusions. A substantial number of patients undergoing LT are not immune to vaccine-preventable viruses at the time of assessment. This presents an opportunity for pre-LT vaccination and in particular younger patients may need to be targeted.