Assessment of the risk of foodborne transmission and burden of hepatitis E in Switzerland

Abstract

The objective of this study was i) to quantify the risk of hepatitis E for Swiss consumers by specified pork products and ii) to estimate the total burden of human food-borne hepatitis E in Switzerland. A quantitative risk assessment from slaughter to consumption was carried out according to the Codex Alimentarius framework. In the hazard characterization, assumptions were made due to the lack of a dose-response relationship for oral exposure to hepatitis E virus (HEV). The prevalence of HEV in 160 pig livers of 40 different Swiss fattening farms was examined and determined to be 1.3% (CI 0.3%; 4.4%). This result was used as input in the risk assessment model, together with data from other published studies. The annual burden of hepatitis E was estimated in terms of Disability Adjusted Life Years (DALY), using data about hepatitis E cases diagnosed between 2010 and 2015 at two major hospitals located in the canton Ticino. Only the risk of foodborne hepatitis E from products containing pork liver was evaluated, as those containing only pork meat could not be evaluated because of lack of data on HEV load in pork. Assuming that successful oral infection occurs in 1% of servings contaminated with high HEV loads (>10 genome copies), and that acute illness develops in 5% of susceptible consumers, the most likely annual number of foodborne hepatitis E cases in Switzerland was estimated to be 1481 (95% CI 552; 4488) if all products containing pork liver were considered. If only high-risk products, such as plain pork liver and liver sausages (e.g. Saucisse au Foie), were considered, the annual number of cases was estimated to be 176 (95% CI 64; 498). We were unable to calculate the total burden of hepatitis E in Switzerland due to lack of data. Yet, for the canton Ticino, it was shown that a significant increase had occurred from <5 DALY per 100,000 inhabitants before 2012 to >50 DALY per 100,000 inhabitants in 2015. This change could partly be due to an increased reporting and higher awareness among medical practitioners. Extrapolation to other regions could be accomplished if detailed information on food consumption patterns were available. Notification of HEV cases and attempts of cases source attribution would improve the basis for risk assessments.

Detection of Hepatitis E Virus RNA in Raw Cured Sausages and Raw Cured Sausages Containing Pig Liver at Retail Stores in Switzerland

“…A quantitative risk assessment following the Codex Alimentarius principles was recently performed in Switzerland in order to predict the exposure of consumers to HEV through food consumption (10). Pork products containing pork liver, in particular those sold raw, were identified as posing the highest risk for the consumer.…”

Hepatitis E virus as a cause of acute hepatitis acquired in Switzerland

“…We successfully implemented nucleic acid‐based diagnosis of hepatitis E . Between November 2011 and December 2016 we observed a steady increase in demand for molecular testing, likely reflecting enhanced awareness for hepatitis E in the Swiss medical community, although a true increase in the incidence of HEV infection and/or the number of symptomatic cases cannot be excluded, as also discussed in a recent study addressing the risk of foodborne HEV transmission in Switzerland . The proportion of positive samples remained roughly constant over the years, allowing us to characterize 93 patients with acute hepatitis E acquired in Switzerland.…”

Foodborne viruses: Detection, risk assessment, and control options in food processing

“…For instance, in the absence of a cell culture based method for detection, the concentration of viruses in samples are often estimated by RT-qPCR in number of genome copies or PCR-detectable genome units/g of product and sometimes in combination with the MPN test Pintó et al, 2009;Masago et al, 2006). Similarly, feeding trial data from other viruses after applying correction factors (Pintó et al, 2009) or from a specific virus strain , or simply an assumption on a threshold dose (Müller et al, 2017), may form the basis of the dose response models. Alternatively, in the absence of a specific dose-response model, an estimation of the number of exposures may be the final step of the risk assessment process (Sarno et al, 2017).…”