Echinococcus multilocularis and Echinococcus granulosus sensu lato are the causative agents of two major zoonotic diseases, alveolar echinococcosis and cystic echinococcosis, respectively, and are ranked among the four most important foodborne parasites worldwide. Although interest in food contamination by taeniid eggs is increasing, the estimation of the number of eggs present in food items is still lacking. Using E. multilocularis eggs isolated from fecal samples of experimentally infected red foxes, an average of 5261 (±1253) mitochondrial DNA copies per egg was estimated by digital PCR (dPCR). Based on this estimation, 47 taeniid DNA samples previously obtained from different food items and identified as positive for E. multilocularis, E. granulosus sensu stricto or Taenia species, were submitted to dPCR to estimate the number of eggs present. In 95.7% of the samples, the contamination was estimated to be caused by one to five eggs, with only one egg in 83.0% of the samples. As detection of such low-level contamination requires sensitive detection methods, a performance comparison between microscopy and molecular methods was conducted using 15 pellets obtained from lettuce wash residues spiked with 0 to 63 E. multilocularis eggs. Two operators performed blinded microscopy, followed by DNA extraction from the examined pellets for real-time PCR detection and then an estimation of the number of eggs by dPCR. A higher sensitivity was obtained with real-time PCR (88.5%) compared to microscopy (40%) in samples containing one to five eggs. The correlation between the number of eggs spiked into the samples and the estimated egg number was strong using dPCR (r = 0.99, p < 0.01), while only moderate with microscopy (r = 0.67, p < 0.05). Estimation of the number of taeniid eggs in food samples by dPCR provides the first quantitative basis for exposure assessment and is important for evaluating the risk of human foodborne infections, with future work needed to address egg viability.
Private consumption of wild boar meat is increasingly widespread across Europe. Notably, only a small proportion of hunted game is processed through approved establishments, while the majority is intended for private consumption. Testing wild boar meat for Trichinella spp. is mandatory when the meat is placed on the market. However, for private consumption this testing may not be carried out, raising public health concerns due to the risk of Trichinella spp. infection. To assess this risk, a survey was conducted in 26 European countries to collect data on the number of hunted wild boars (Sus scrofa) intended for private consumption and the prevalence of Trichinella spp. in wild boars, and to compare legislation and operational practices related to testing requirements, sample handling, diagnostic methods, training requirements, reporting procedures, mandatory measures for positive samples, penalties for non-compliance, and awareness-raising activities. Findings revealed significant heterogeneity in testing obligations, sample handling procedures, laboratory requirements, and enforcement mechanisms. While some countries mandate systematic testing and subsidize costs, others rely on voluntary testing or impose no requirements, leaving consumers at higher risk. Reported prevalence of Trichinella spp. in wild boar varied widely, ranging from 0% to over 6% across countries and years, though data availability was often inconsistent. Awareness campaigns and hunter training remain limited in many regions, contributing to underreporting, low compliance, and insufficient risk perception. Key challenges include lack of hunter engagement, insufficient testing facilities, and variable penalties for non-compliance. To mitigate risks, we recommend harmonizing surveillance strategies, expanding education and communication initiatives, ensuring accessible and affordable testing, and strengthening collaboration between veterinary authorities and hunting communities. Such measures are essential to reduce the zoonotic risk of trichinellosis linked to privately consumed wild boar meat in Europe.
Neutrophils exert diverse functions in parasitic infections, including pathogen clearance and regulation of inflammation. However, their specific roles in the early stage of infection with Clonorchis sinensis (C. sinensis), a significant foodborne parasite that dwells in the bile ducts, remain largely unknown. In this study, FVB mice were orally infected with 50C. sinensis metacercariae, and neutrophils were depleted using an anti-Ly6G antibody whereas IgG isotype served as the control. Mice were sacrificed 14 days post-infection, and serum and liver tissue were collected to assess hepatobiliary injury. Hepatic leukocyte changes were analyzed by flow cytometry, and associated cytokine/chemokine expression was detected by qPCR. Results showed that neutrophil-depleted mice exhibited significantly aggravated hepatobiliary injury, as evidenced by elevated serum ALT/AST, epithelial hyperplasia, inflammatory infiltration, and ductal dilatation. Neutrophil depletion also exacerbated infection-induced hepatic fibrosis, indicated by increased collagen fiber deposition and increased mRNA levels of Acta2, Col3a1 and Tgfb1. Flow cytometry revealed reduced absolute T cell counts but increased CD45+CD11bloF4/80hi Kupffer cells and CD45+CD11b+Ly6G-Ly6Clo monocytes in neutrophil-depleted infected mice. Additionally, neutrophil depletion increased mRNA levels of Axl, Mertk, Nr4a1, Cx3cr1, Cx3cl1, Tnfα, Il1b, Il10 and Ccl2, while down-regulating Cxcl1 in infected mice. Collectively, these findings indicate a protective role of neutrophils in the early C. sinensis infection in this murine model. Neutrophil depletion induces compensatory expansion of Kupffer cells and Ly6Clo monocytes, forming a pro-inflammatory and pro-fibrotic microenvironment that accelerates liver damage. The results highlight neutrophils as important modulators of hepatic immune responses during clonorchiasis and point to the need for further investigation into neutrophils-mediated regulation of helminth-associated liver pathology.
In fillets of cultured common carp intended for human consumption, large cysts containing larvae (metacercariae) of trematodes (Digenea) were found. These larvae belong to the family Diplostomidae, whose adults most often mature in birds and mammals. Although humans may acquire diplostomid infection only incidentally and the number of reported human cases of diplostomosis is not very high, except for alariosis, the presence of metacercariae in carp fillets is an epidemiological and economic concern due to the popularity of carp as a food source in Central and Eastern Europe. Morphological and molecular data (sequencing of three genetic markers) did not allow the assignment of the larvae to any known diplostomid genus.
