Assessing the Contamination of Food and the Environment With Taenia and Echinococcus Eggs and Their Zoonotic Transmission

Abstract

Purpose of Review: Cystic and alveolar echinococcosis, caused by Echinococcus granulosus sensu lato and E. multilocularis, respectively, and Taenia solium cysticercosis are serious but neglected zoonotic diseases, caused by extra-intestinal cestode (tapeworm) infections. Humans are dead-end hosts for Echinococcus spp and acquire the infections by uptake of parasite eggs, either with contaminated food or via exposure by hand-mouth contact to eggs derived from the contaminated environment, including skin or coat of definitive hosts. Data related with the production of eggs of these parasites, their survival in the environment and the methodology for detection in food and environmental samples are summarized. Recent Findings: The detection of taeniid DNA, more specifically from E. multilocularis, in food and soil has recently been described in some European countries. These findings have been directly connected with an increase in prevalence of human infections in countries like Poland. Summary: The isolation and molecular identification of taeniid eggs is technically challenging and little standardized. The detection of taeniid DNA per se does not imply viability of eggs, and this must be considered when interpreting molecular results for transmission risk. Finally, easy, affordable, and sensitive methods replacing animal experiments should be developed to assess the viability of taeniid eggs isolated from environmental and food/water sources.