A Quantitative Risk Assessment for human Taenia solium exposure from home slaughtered pigs in European countries

Abstract

Taenia solium (T. solium) is a zoonotic tapeworm that is responsible for about a third of all preventable epilepsy in humans, mainly in developing countries. In Europe, adequate biosecurity of pig housing and proper meat inspection management have decreased the incidence of T. solium taeniosis and cysticercosis. Pigs that are slaughtered at home may be raised poorly and not undergo meat inspection. As a result, home slaughtered pork could be a risk factor for exposure to T. solium. The aim of this study was to quantify the risk of human T. solium exposure from home slaughtered pork, in comparison to the risk from controlled slaughtered pork, in European countries. A quantitative production-to-consumption risk assessment model (QMRA) was developed. Porcine prevalence data, the percentage of pigs slaughtered at home, sensitivity of meat inspection, the cyst distribution in pork and pork consumption in five different European countries were included. This was combined with literature about cooking of pork, to calculate the number of infected pork portions eaten per year in a country. Recognizing the uncertainties in the data, the model still clearly shows a ten times higher prevalence of infected portions from home slaughtered pork compared to controlled slaughtered pork. This difference is brought about by the higher prevalence of cysticercosis in the pigs that are home raised and slaughtered. Meat inspection does not affect the higher exposure from home slaughtered pork, because the sensitivity of meat inspection is low in general when pigs have a mild infection. The model demonstrates that cooking meat effectively decreases the number of infected pork portions and thus lowers the risk of exposure. Besides the findings, this QMRA has shown the knowledge gaps and what kind of future research is needed to improve the QMRA. This includes systematically reporting porcine cysticercosis cases in slaughterhouses and studies on raw meat consumption in different countries and cultures. Moreover, developing a dose response model for T. solium to estimate the incidence of human taeniosis is recommended. When more data becomes available, this QMRA model could be implemented in intervention strategies concerning T. solium in Europe and beyond.