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Molecular identification of rare human infectious pathogens appears to be one of the most relevant current methods for rapid diagnosis and management of patients. PCR techniques, in particular real-time quantitative PCR, are best suited for the detection of DNA from the pathogens, even at low concentrations. Echinococcosis infections are due to helminths of the Echinococcus genus, with closely related species involved in parasitic lesions affecting animals and, accidentally, humans. We developed a multiplex qPCR (MLX qPCR) assay allowing for the detection of four Echinococcus species involved in Europe in alveolar echinococcosis (AE) and cystic echinococcosis (CE) (Echinococcus multilocularis, E. granulosus sensu stricto, E. ortleppi, and E. canadensis), based on short mitochondrial targets. A collection of 81 fresh and formalin-fixed paraffin-embedded tissues (FFPE) of AE and CE lesions was assembled. The qPCR assays were performed in triplex for Echinococcus spp. detection, associated with a qPCR inhibitor control. A duplex qPCR was also designed to enable diagnosis of two other dead-end helminthiases (cysticercosis (Taenia solium), and toxocariasis (Toxocara cati and T. canis)). The sensitivity of the qPCR was assessed and ranged from 1 to 5 × 10 -4  ng/μL (seven PCR assays positive), corresponding to 37-42 cycles for quantifiable DNA. The specificity was 100% for all the targets. This multiplex qPCR, adapted to low amounts of DNA can be implemented in the laboratory for the rapid molecular diagnosis of Echinococcosis species., (© J. Knapp et al., published by EDP Sciences, 2023.)

Confirmed diagnosis of alveolar echinococcosis (AE) is based on pathological criteria and molecular evidence. This parasite-borne disease, caused by the cestode Echinococcus multilocularis, sparingly involves humans as a dead-end host. In humans, the parasite mainly colonizes the liver but can colonize any organ and cause atypical forms, often difficult to characterize clinically. Moreover, molecular methods may be suitable to make the diagnosis of AE in cases of atypical forms, extra-hepatic localizations, or immunosuppressed patients. The aim of this study was to determine the most relevant published PCR techniques, for diagnosis of AE in patients and adopt the best strategy for molecular diagnosis depending on the nature of the tested sample. In this study, we evaluated nine end-point PCR assays and one real-time PCR assay (qPCR), targeting mitochondrial genes, using a total of 89 frozen or formalin-fixed paraffin-embedded (FFPE) samples from either 48 AE or 9 cystic echinococcosis patients. Targeted fragment-genes ranged from 84 to 529 bp. Six PCR assays were able to amplify the DNA of 100% of the frozen AE-samples and for one PCR, 69.8% of the FFPE AE-samples. The 16S rrnL PCR (84 bp) was positive in PCR for 77% of the AE samples and in qPCR for 86.5%. The sensitivity of the PCR assays was higher for fresh samples and FFPE samples stored for less than 5 years. The qPCR assay further increased sensitivity for the tested samples, confirming the need for the development of an Echinococcus spp. qPCR to improve the molecular diagnosis of echinococcoses., (© J. Knapp et al., published by EDP Sciences, 2022.)

Echinococcus multilocularis eggs are deposited on the ground with the faeces of the carnivore definitive hosts. A reliable assessment of the spatial distribution of E. multilocularis eggs in environments used by humans is crucial for the prevention of alveolar echinococcosis (AE). This study was conducted in 192 rural and 71 urban vegetable gardens in AE endemic areas of north-eastern France. Its objective was to explore the relationship between the spatial distribution of E. multilocularis estimated from the collection and molecular analysis of two types of samples: faeces and soil. A total of 1024 carnivore faeces and 463 soil samples were collected and analysed by real-time PCR. No fox droppings and no positive soil samples were collected from the urban gardens. Positive soil samples, positive carnivore faeces, or both, were found in 42%, 24% and 6% of the sampled rural gardens, respectively. No significant association was found between the detection of E. multilocularis in soil samples collected from 50 gardens during a single sampling session and the extent and frequency of deposits of fox and cat faeces collected during repeated sampling sessions conducted in the previous months. In 19/50 gardens, E. multilocularis was detected in the soil while no positive faeces had been collected in the previous 12 months. Conversely, in 8/50 gardens, no soil samples were positive although positive faeces had been collected in the previous months. Collecting and analysing faeces provide information on soil contamination at a given time, while analysing soil samples provides an overview of long-term contamination., (© A.M. Da Silva et al., published by EDP Sciences, 2021.)

Echinococcus multilocularis, Toxoplasma gondii and Toxocara spp. are foodborne parasites whose eggs or oocysts are spread in the environment via canid or felid faeces. They can cause infections in humans following the raw consumption of contaminated fruit or vegetables. In this study, their occurrence was investigated by quantitative polymerase chain reaction (qPCR) in 254 carnivore faeces deposited in 94 kitchen gardens of northeastern France that were sampled between two and six times from October 2011 to April 2013. Less than 25% of the sampled kitchen gardens contained more than 75% of the collected faeces. Of the 219 faeces that could be attributed to an emitter, cat accounted for 58%, fox for 32% and dog for 10%. Echinococcus multilocularis was detected in 35%, 11% and 7% of fox, dog and cat faeces, respectively, and Toxocara spp. in 33%, 12% and 5.5% of cat, fox and dog faeces, respectively. Toxoplasma gondii was detected in 2/125 cat faeces and 2/21 dog faeces. The 34 faeces that tested positive for E. multilocularis were found in only 19 out of the 94 sampled kitchen gardens, and the 40 faeces that tested positive for Toxocara spp. were found in 28 of them. Consequently, some kitchen gardens appeared particularly at risk of human exposure to foodborne parasites, including E. multilocularis responsible for alveolar echinococcosis (AE), which is a serious zoonosis. In endemic areas, kitchen garden owners should be informed about the zoonotic risk linked to carnivore faeces deposits and encouraged to set up preventive measures., (© M.-L. Poulle et al., published by EDP Sciences, 2017.)

Echinococcus multilocularis, a cestode parasite responsible for alveolar echinococcosis in humans, is often reported in Europe. It involves red foxes, domestic dogs, and domestic and wild cats as definitive hosts. The parasite infects small mammals and accidentally humans as intermediate hosts and develops in a similar way to a tumor, usually in the liver. Domestic animals are suspected of playing a role in parasite transmission, but this is rarely proven. Moreover, the role of domestic cats is thought to be small, because of experimental studies showing incomplete development of the parasite observed in their intestines. In the present study, we investigated copro-sampling performed in a rural and highly endemic area in Eastern France, on carnivore feces (n = 150). From these samples, the parasite was detected and identified by DNA analysis using quantitative PCR targeting part of a mitochondrial gene (Em-qPCR). Taeniid eggs were isolated from positive-Em-qPCR samples by flotation, and species identification was confirmed by sequencing on DNA extracts. From a total of 43 copro-samples from cats, four tested positive for E. multilocularis by the Em-qPCR. In two of these, we found parasite eggs that were identified as E. multilocularis. This finding was confirmed by sequencing, while one dog stool out of 61 collected was found to be positive, no egg was detectable. At the same time, 34% of fox stools tested positive for the parasite. The present study challenges the current idea that cats are only of minor significance in the E. multilocularis life cycle., (© J. Knapp et al., published by EDP Sciences, 2016.)

Alveolar echinococcosis (AE) is an endemic zoonosis in France due to the cestode Echinococcus multilocularis. The French National Reference Centre for Alveolar Echinococcosis (CNR-EA), connected to the FrancEchino network, is responsible for recording all AE cases diagnosed in France. Administrative, epidemiological and medical information on the French AE cases may currently be considered exhaustive only on the diagnosis time. To constitute a reference data set, an information system (IS) was developed thanks to a relational database management system (MySQL language). The current data set will evolve towards a dynamic surveillance system, including follow-up data (e.g. imaging, serology) and will be connected to environmental and parasitological data relative to E. multilocularis to better understand the pathogen transmission pathway. A particularly important goal is the possible interoperability of the IS with similar European and other databases abroad; this new IS could play a supporting role in the creation of new AE registries., (© A. Charbonnier et al., published by EDP Sciences, 2014.)

Serological diagnosis of alveolar echinococcosis (AE) is a key element for efficient patient treatment management. A rapid immunochromatography test kit (ICT) using the recombinant Em18 antigen (rEm18) was recently developed. The aim of our study was to assess this test on a panel of sera from French patients with alveolar echinococcosis and control patients. In a blind test, a total of 112 serum samples were tested including samples of AE (n = 30), cystic echinococcosis [CE] (n = 15), and polycystic echinococcosis [PE] (n = 1). For the comparison, 66 sera from patients with hepatocarcinoma, fascioliasis, toxocariasis, Caroli's disease, or autoimmune chronic active hepatitis were used. The diagnostic test sets we used were the rEm18-ICT and two validated ELISAs with rEm18 and Em2-Em18 antigens, respectively. For the ICT, 27/30 sera from AE patients, 4/15 sera from CE patients and the PE patient serum were positive. One serum from the control panel (toxocariasis) was positive for the ICT. The rEm18-ICT sensitivity (90.0%) and specificity (92.7%) for detection of Em18-specific antibodies confirmed it as a relevant tool for AE diagnosis. The rEm18-ELISA had a sensitivity of 86.7% and specificity of 91.5%, and the Em2-Em18-ELISA had a sensitivity of 96.7% and specificity of 87.8%. However, when AE patient sera are recorded as weak in intensity with the ICT, we recommend a double reading and use of a reference sample if the ICT is used for patient follow-up., (© J. Knapp et al., published by EDP Sciences, 2014.)