Significant increase of Echinococcus multilocularis prevalencein foxes, but no increased predicted risk for humans

The emergence of the zoonotic tapeworm Echinococcus multilocularis, causative agent ofalveolar echinococcosis (AE), poses a public health risk. A previously designed risk mapmodel predicted a spread of E. multilocularis and increasing numbers of alveolar echinococ-cosis patients in the province of Limburg, The Netherlands. This study was designed todetermine trends in the prevalence and worm burden of E. multilocularis in foxes in a popu-lar recreational area in the southern part of Limburg to assess the risk of infection for humansand to study the prevalence of E. multilocularis in dogs in the adjacent city of Maastricht.Thirty-seven hunted red foxes were tested by the intestinal scraping technique and nestedPCR on colon content. Additionally, 142 fecal samples of domestic dogs from Maastrichtwere analyzed by qPCR for the presence of E. multilocularis.In foxes, a significantly increased prevalence of 59% (95% confidence interval 43–74%)was found, compared to the prevalence of 11% (95% CI 7–18%) in 2005–2006. Average wormburden increased to 37 worms per fox, the highest since the first detection, but consistentwith the prediction about the parasite population for this region. Updated prediction onthe number of AE cases did not lead to an increase in previous estimates of human AE casesup to 2018. No dogs in the city of Maastricht tested positive, but results of questionnairesshowed that deworming schemes were inadequate, especially in dogs that were consideredat risk for infection.