A new species of Versteria (Cestoda: Taeniidae) parasitizing Neogale vison and Lontra canadensis (Carnivora: Mustelidae) from Western Canada.

Via molecular and morphological analyses, we describe adult specimens of a new species of Versteria (Cestoda: Taeniidae) infecting mink and river otter (Carnivora: Mustelidae) in Western Canada, as well as larval forms from muskrat and mink. These sequences closely matched those reported from adult specimens from Colorado and Oregon, as well as larval infections in humans and a captive orangutan. We describe here a new species from British Columbia and Alberta (Canada), Versteria rafei n. sp., based upon morphological diagnostic characteristics and genetic distance and phylogeny. Versteria rafei n. sp. differs from the three other described species of the genus in the smaller scolex and cirrus sac. It also differs from V. mustelae (Eurasia) and V. cuja (South America) by having an armed cirrus, which is covered in hair-like bristles, and in the shape of its hooks, with a long thorn-like blade, and short or long handle (vs. a short sharply curved blade and no difference in handle size in previously described species). The poorly known V. brachyacantha (Central Africa) also has an armed cirrus and similarly shaped hooks. However, it differs from the new species in the number and size of hooks. Phylogenetic analysis of the cox1 and nad1 mitochondrial regions showed that our specimens clustered with isolates from undescribed adults and larval infections in North America, and separate from V. cuja, confirming them to be a distinct species from the American Clade.

Current status of cystic echinococcosis control in the Falkland Islands: has elimination been achieved?

Attempts to control cystic echinococcosis (CE) caused by Echinococcus granulosus in the Falkland Islands have been ongoing for over 50 years. No human cases have been recorded since the 1980s but there is a need to establish if the parasite has been completely eliminated from domestic animals. A study was carried out in 2018/2019 to identify dogs infected with E. granulosus using copro-antigen and copro-polymerase chain reaction (PCR) analysis. In addition, annual slaughter data were analysed to establish infection levels of E. granulosus and 2 other taeniid parasites. Results showed that 4 out of 589 dogs (0.7%) tested positive by copro-antigen analysis. Results from similar surveys carried out in 2010, 2012 and 2014 showed 17 (3%), 0 and 6 (1%) copro-antigen-positive dogs, respectively, with 8 dogs being confirmed by PCR in 2010. Annual abattoir data showed that from 2006 to 2020, 36 sheep were identified with E. granulosus (mean 0.0055%), 14 186 sheep with Taenia hydatigena (mean 2.2%) and 465 with Taenia ovis (mean 0.072%). Prevalences of T. hydatigena and T. ovis showed spontaneous rises in certain years where the infections could also be detected in lambs indicating that viable taeniid eggs were present. Observations of farm management procedures indicated that there were occasions when dogs could get access to infective taeniid material. In conclusion, E. granulosus is still present in sheep and dogs but at low prevalences. The increasing presence of T. hydatigena however, indicates that control measures are defective in some areas and there is potential for a re-emergence of CE.

High overlap of zoonotic helminths between wild mammalian predators and rural dogs - an emerging One Health concern?

The concept of One Health emphasizes the interdependence of human, animal and environmental health and is of growing significance, in part owing to the problems related to emerging infectious diseases of wildlife origin. Wild mammalian predators are a potential risk factor for transmission of zoonotic pathogens to domesticated animals and humans. This is especially relevant in rural areas, where transmission of zoonotic pathogens can occur particularly efficiently when free-ranging dogs are present. The main aim of this study was to determine helminth infections among wild mammalian predators and evaluate the overlap between helminth faunas of wild mammals and dogs. Scat samples of predators were collected in coastal areas of Western Estonia and genetic methodology applied for the correct identification of predator species from their scat. Parasitic helminths of mammalian predators in the scat samples were analysed and compared with dog data from a previous study. High helminth prevalence (~90%) was found in dominant predator species in the area, namely the red fox (Vulpes vulpes) and golden jackal (Canis aureus). Moreover, the helminth fauna of both wild species, including potentially zoonotic helminths, overlapped largely with that of rural dogs in the same area. The results, together with the ones from earlier parasitological studies among humans in Estonia, emphasize the potential risk of pathogen transmission from wild mammalian predators to dogs and from dogs to humans, making parasitic diseases of wildlife a One Health concern.

Free-ranging rural dogs are highly infected with helminths, contaminating environment nine times more than urban dogs.

Regardless of the highly efficient anthelmintics available and the control measures taken by dog owners and veterinarians, gastrointestinal parasites, especially zoonotic helminths, are still abundant in dogs and pose a health risk to humans. Free-ranging dogs in rural areas can be an important source of helminth infection. The aims of the present work were to collect scats of rural dogs, determine the environmental contamination caused by helminth infections among rural dogs of Western Estonia, analyse how diet affects helminth infection rate and compare the findings to a previous study focusing on dog helminths in urban areas of Estonia. To differentiate the scats of dogs from other sympatric canids, a genetic method was applied. Of 328 samples, genetic analysis identified 84 scats belonging to dogs, of which 87.0% were infected with helminths. A high proportion of rural dog scats harboured eggs of Taeniidae (65.5%), followed by Trichuris spp./Eucoleus spp. (15.5%), Uncinaria stenocephala (14.7%) and Toxocara canis (4.3%). Coinfections occurred in 34.5% of the samples, being the most common between Taeniidae and U. stenocephala (41.4%). The intensity model indicated higher helminth infection rate in rural dogs preying on rodents and game. In comparison to urban dogs, rural dogs were nine times more likely to be infected with intestinal parasites. These results emphasize the need to implement measures to reduce helminth infections in dogs living in rural areas of Western Estonia. Among a complex of measures to be taken, we suggest that it is also important to diagnose which gastrointestinal parasite species infect dogs to determine specific anthelmintic treatment against these parasites.

Rodents of Senegal and their role as intermediate hosts of Hydatigera spp. (Cestoda: Taeniidae).

Hydatigera (Cestoda: Taeniidae) is a recently resurrected genus including species seldom investigated in sub-Saharan Africa. We surveyed wild small mammal populations in the areas of Richard Toll and Lake Guiers, Senegal, with the objective to evaluate their potential role as intermediate hosts of larval taeniid stages (i.e. metacestodes). Based on genetic sequences of a segment of the mitochondrial DNA gene cytochrome c oxidase subunit 1 (COI), we identified Hydatigera parva metacestodes in 19 out of 172 (11.0%) Hubert's multimammate mice (Mastomys huberti) and one out of six (16.7%) gerbils (Taterillus sp.) and Hydatigera taeniaeformis sensu stricto metacestodes in one out of 215 (0.5%) Nile rats (Arvicanthis niloticus). This study reports epidemiological and molecular information on H. parva and H. taeniaeformis in West African rodents, further supporting the phylogeographic hypothesis on the African origin of H. parva. Our findings may indicate significant trophic interactions contributing to the local transmission of Hydatigera spp. and other parasites with similar life-cycle mechanisms. We therefore propose that further field investigations of rodent population dynamics and rodent-borne infectious organisms are necessary to improve our understanding of host-parasite associations driving the transmission risks of rodent parasites in West Africa.

Helminth infections of wild European gray wolves (Canis lupus Linnaeus, 1758) in Lower Saxony, Germany, and comparison to captive wolves.

This study aimed to investigate the endoparasite fauna of wild European gray wolves, which are currently recolonizing Germany. In total, 69 fecal samples of wild wolves were collected in Lower Saxony, Germany, from 2013 to 2015, analyzed by the sedimentation-flotation and McMaster techniques and compared to previous results on captive European Gray wolves living in zoological gardens in Germany. In addition to coproscopy, taeniid-positive samples from wild as well as captive wolves were differentiated by amplification and sequencing of small subunit ribosomal RNA (SSU rRNA) and NADH dehydrogenase 1 (nad1) gene fragments. Missing Taenia krabbei SSU rRNA reference sequences were generated from two T. krabbei specimens. Overall, 60.87% (42/69) of wild wolve samples were microscopically positive for at least one of seven egg types. Capillaria/Eucoleus spp. showed the highest frequency (31.88% [22/69]), followed by Taeniidae (21.74% [15/69]), Ancylostomatidae (20.29% [14/69]), Alaria alata (15.94% [11/69]), Toxocara canis (13.04% [9/69]), and Toxascaris leonina and Trichuris vulpis (each 5.80% [4/69]). Amplification of SSU rRNA was successful for 7/15 Taeniidae-positive samples from wild and 20/39 samples from captive wolves, revealing T. hydatigena in two and 14 samples, respectively. Taenia krabbei was detected in two further samples of wild and three samples of captive wolves, while for the remaining samples, no differentiation between T. serialis/T. krabbei was possible. Echinococcus spp. were not detected. Sequence comparisons revealed that the SSU rRNA gene fragment was not suitable to differentiate between T. serialis and T. krabbei. Therefore, the use of this fragment alone cannot be recommended for species identification in future studies.

Experimental and field investigation of non-biting flies as potential mechanical vectors of Echinococcus granulosus eggs.

Synanthropic fly species can be potential mechanical vectors of many infectious agents. The potential of the flies to carry Echinococcus granulosus eggs is not fully documented. The purpose of the present study was to determine the possible role of non-biting flies to carry taeniid eggs. A total of 210 flies were collected from seven selected sites in areas of Kerman city, southeastern Iran from November 2016 to May 2017. Adult flies were live-caught using sweeping nets. Flies were placed individually in small glass bottles and transported to the laboratory. All the flies were killed by deep freezing and then identified to the species level using both morphological and molecular methods. The flies were homogenized in test tubes and genomic DNA was extracted and amplified by PCR. PCR protocols were used both to identify the live-caught flies to the species level, and for the detection of E. granulosus. The laboratory reared second generation flies were experimentally exposed to dog feces manually spiked by Echinococcus eggs. Two runs of experiments with 1-3 h of exposure were designed. For each experiment 20 flies were selected from the stock colony and were starved for three days. After each experiment, the flies were frozen for further molecular studies. The dominant fly species were Musca domestica and Lucilia sericata. No eggs were found on the body surface and/or guts of live-caught flies. After the first hour of exposure, 60%, of the flies of both species were found to harbor Echinococcus eggs. However, in the case of L. sericata 50% of the flies harbored Echinococcus eggs after 3 h of exposure. Results of the present study indicate the probable role of synanthropic flies in harboring Echinococcus eggs and mechanical transmission of cystic echinococcosis. When the helminth eggs are susceptible to desiccation grooming flies can remove many of eggs from exterior surfaces of them. Despite this result the role of synanthropic flies in the transmission of certain helminthiases should not be discounted because of their vagility and feeding mechanisms.

Origin, differentiation and functional ultrastructure of egg envelopes in the cestode Echinococcus multilocularis Leuckart, 1863 (Cyclophyllidea: Taeniidae).

The origin, differentiation and functional ultrastructure of oncospheral or egg envelopes in Echinococcus multilocularis Leuckart, 1863 were studied by transmission electron microscopy (TEM) and cytochemistry. The purpose of our study is to describe the formation of the four primary embryonic envelopes, namely vitelline capsule, outer envelope, inner envelope and oncospheral membrane, and their transformation into the oncospheral or egg envelopes surrounding the mature hexacanth. This transformation takes place in the preoncospheral phase of embryonic development. The vitelline capsule and oncospheral membrane are thin membranes, while the outer and inner envelopes are thick cytoplasmic layers formed by two specific types of blastomeres: the outer envelope by cytoplasmic fusion of two macromeres and the inner envelope by cytoplasmic fusion of three mesomeres. Both outer and inner envelopes are therefore cellular in origin and syncytial in nature. During the advanced phase of embryonic development, the outer and inner envelopes undergo great modifications. The outer envelope remains as a metabolically active layer involved in the storage of glycogen and lipids for the final stages of egg development and survival. The inner envelope is the most important protective layer because of its thick layer of embryophoric blocks that assures oncospheral protection and survival. This embryophore is the principal layer of mature eggs, affording physical and physiological protection for the differentiated embryo or oncosphere, since the outer envelope is stripped from the egg before it is liberated. The embryophore is very thick and impermeable, consisting of polygonal blocks of an inert keratin-like protein held together by a cementing substance. The embryophore therefore assures extreme resistance of eggs, enabling them to withstand a wide range of environmental temperatures and physicochemical conditions.

Definitive Hosts of Versteria Tapeworms (Cestoda: Taeniidae) Causing Fatal Infection in North America.

We previously reported fatal infection of a captive Bornean orangutan with metacestodes of a novel taeniid tapeworm, Versteria sp. New data implicate mustelids as definitive hosts of these tapeworms in North America. At least 2 parasite genetic lineages circulate in North America, representing separate introductions from Eurasia.

Echinococcus multilocularis Leuckart, 1863 (Taeniidae): new data on sperm ultrastructure.

The present study establishes the ultrastructural organisation of the mature spermatozoon of Echinococcus multilocularis, which is essential for future research on the location of specific proteins involved in the sperm development in this species and also in Echinococcus granulosus. Thus, the ultrastructural characteristics of the sperm cell are described by means of transmission electron microscopy. The spermatozoon of E. multilocularis is a filiform cell, which is tapered at both extremities and lacks mitochondria. It exhibits all the characteristics of type VII spermatozoon of tapeworms, namely a single axoneme, crested bodies, spiralled cortical microtubules and nucleus, a periaxonemal sheath and intracytoplasmic walls. Other characteristics observed in the male gamete are the presence of a >900-nm long apical cone in its anterior extremity and only the axoneme in its posterior extremity. The ultrastructural characters of the spermatozoon of E. multilocularis are compared with those of other cestodes studied to date, with particular emphasis on representatives of the genus Taenia. The most interesting finding concerns the presence of two helical crested bodies in E. multilocularis while in the studied species of Taenia, there is only one crested body. Future ultrastructural studies of other species of the genus Echinococcus would be of particular interest in order to confirm whether or not the presence of two crested bodies is a characteristic of this genus.

High-resolution melting analysis (HRM) for differentiation of four major Taeniidae species in dogs Taenia hydatigena, Taenia multiceps, Taenia ovis, and Echinococcus granulosus sensu stricto.

Tapeworms of the genus Taenia include several species of important parasites with considerable medical and veterinary significance. Accurate identification of these species in dogs is the prerequisite of any prevention and control program. Here, we have applied an efficient method for differentiating four major Taeniid species in dogs, i.e., Taenia hydatigena, T. multiceps, T. ovis, and Echinococcus granulosus sensu stricto. High-resolution melting (HRM) analysis is simpler, less expensive, and faster technique than conventional DNA-based assays and enables us to detect PCR amplicons in a closed system. Metacestode samples were collected from local abattoirs from sheep. All the isolates had already been identified by PCR-sequencing, and their sequence data were deposited in the GenBank. Real-time PCR coupled with HRM analysis targeting mitochondrial cox1 and ITS1 genes was used to differentiate taeniid species. Distinct melting curves were obtained from ITS1 region enabling accurate differentiation of three Taenia species and E. granulosus in dogs. The HRM curves of Taenia species and E .granulosus were clearly separated at Tm of 85 to 87 °C. In addition, double-pick melting curves were produced in mixed infections. Cox1 melting curves were not decisive enough to distinguish four taeniids. In this work, the efficiency of HRM analysis to differentiate four major taeniid species in dogs has been demonstrated using ITS1 gene.

Fatal metacestode infection in Bornean orangutan caused by unknown Versteria species.

A captive juvenile Bornean orangutan (Pongo pygmaeus) died from an unknown disseminated parasitic infection. Deep sequencing of DNA from infected tissues, followed by gene-specific PCR and sequencing, revealed a divergent species within the newly proposed genus Versteria (Cestoda: Taeniidae). Versteria may represent a previously unrecognized risk to primate health.

Environmental contamination with feces of free-roaming dogs and the risk of transmission of Echinococcus and Taenia species in urban regions of southeastern Iran.

BACKGROUND: Dogs are the most important definitive hosts of zoonotic taeniid helminths worldwide. Different Echinococcus and Taenia species of domestic and wild carnivores pose a potential risk to human population. High populations of free-roaming dogs (FRDs) in urban areas of Iran and widespread contamination of the environment with dog feces is a potential source of infecting people living in the urban regions with cystic echinococcosis (CE). Our knowledge on the risk of CE transmission in the urban settings in the endemic regions is limited. The present study surveyed the species and genotypes of E. granulosus sensu lato and other taeniids by examining feces of free-roaming dogs in the urban areas in the city of Kerman, southeastern Iran. METHODS: The city was divided into 100 consecutive blocks of which 25 blocks were randomly selected. Fecal samples of FRDs were counted, mapped and fresh samples were collected. Then Zinc chloride flotation, and sequential sieving was performed, and the samples were examined under an inverted microscope. Single individual taeniid eggs were isolated, partial nad1 gene was amplified and sequenced to identify species and genotypes. RESULTS: In total 5607 fecal samples of dogs were mapped and 83 fresh samples were collected. Taeniid eggs were detected in nine fecal samples (10.8%) from seven out of the 25 city blocks (28.0%). Echinococcus eggs were found in four samples (4.8%) from three city blocks, two samples containing E. granulosus sensu stricto (2.4%), two samples containing E. canadensis G6/7 (2.4%). In addition, three samples contained eggs of Taenia hydatigena (3.6%), and one sample of Taenia serialis (1.2%). CONCLUSIONS: This study documented the potential risk of CE transmission to humans resulting from the feces of dogs roaming freely in urban areas.

Molecular Screening of Echinococcus spp. and Other Cestodes in Wild Carnivores from Central Italy.

Tapeworm infections are among the most relevant parasitic diseases in humans and animals. Tapeworms from the Genus Echinococcus are particularly important as they can cause cystic or alveolar echinococcosis. A molecular screening was performed on 279 fecal samples collected from carcasses of wild carnivores from Central Italy using PCR targeting diagnostic fragments of nad1, rrnS, and nad5 genes. Samples positive for either Taenia spp. or Echinococcus granulosus were sequenced to taxonomically identify the parasitic DNA. Of the 279 samples, 134 (48.0%) gave positive results in the multiplex PCR. Only one (0.4%) sample from an Apennine wolf tested positive for Echinococcus granulosus sensu stricto (genotype G3), whereas no sample tested positive for E. multilocularis. The most frequently detected tapeworms were: Mesocestoides corti (syn M. vogae) (12.9%), M. litteratus (10.8%), Taenia serialis (9.3%), and T. hydatigena (6.5%), other tapeworms were rarely detected. The results suggest that Echinococcus infections in Central Italy do not seem to be sustained by sylvatic cycles, confirming the absence of E. multilocularis in Central Italy. The survey corroborates, yet again, the importance of passive surveillance of wild animals that can serve as reservoirs for zoonotic pathogens, especially on wild canids that in other areas are strongly implicated in the transmission of E. granulosus and E. multilocularis.

Dispersal of taeniid eggs: Experimental faecal contamination of forest environment followed by DNA detection in wild berries.

To understand Taeniidae epidemiology, the principles of egg-dispersion dynamics under natural conditions must be known. In this study, non-zoonotic Taenia laticollis was used as a model parasite for the family Taeniidae (including Echinococcus spp.). An experiment to investigate dispersion from contaminated faeces to the surroundings was performed both with bilberries (Vaccinium myrtillus) and lingonberries (Vaccinium vitis-idaea), both of which are commercially harvested wild berries in Finland. For this experiment, 30 g of fox faeces was inoculated with 30,000 T. laticollis eggs for the bilberry experiment and 100,000 eggs for the lingonberry experiment. The faecal material was placed in the middle of good berry growth areas in four locations for bilberries and eight locations for lingonberries. After 41-42 days, berries at different distances (0-15 m) from the original contamination spot were collected and delivered to our laboratory. DNA was extracted from washed and sieved material and analysed using T. laticollis-specific semi-quantitative SYBR Green real-time polymerase chain reaction (qPCR). Taenia laticollis-specific DNA was recovered from 67% (8/12) of bilberry samples but not reliably from any of the lingonberry samples 0% (0/24), although the exposure dose was higher for those. The qPCR results suggest that under natural conditions, taeniid egg dispersion from the contamination spot is demonstrated but attachment is berry specific. The surface of bilberries may be more adhesive for taeniid eggs than the waxier and harder pericarp of the lingonberries or there might be a difference in the dispersal mechanism caused by different biotopes.

Fatal infection with Versteria sp. in a muskrat, with implications for human health.

The Taeniidae tapeworms are a family of helminths that have a similar life cycle, with intermediate hosts developing characteristic cysts in visceral organs. We describe here a case in Pennsylvania, USA, of fatal Versteria infection in a muskrat (Ondatra zibethicus), which, to our knowledge, has not been reported to develop disease associated with infection. Postmortem examination revealed widespread tissue loss and replacement by solid-bodied cestode larvae with minimal adjacent inflammation in many visceral organs, most severe in the lungs, liver, and brain. Key morphologic features via histology included cephalic structures and short rostellar hooklets, which are characteristic for the genus. Genetic characterization confirmed the cestode as being an undescribed lineage of Versteria that has been implicated as the cause of severe morbidity and mortality in humans and nonhuman primates in North America. Considering the zoonotic significance of this pathogen, our report expands on the limited literature regarding disease caused by Versteria and emphasizes the need to identify the causative tapeworm more accurately, especially in rodent intermediate hosts given that previous reports do not have molecular confirmation of species.

Taenia laticollis and a potentially novel Taenia species from the Eurasian lynx (Lynx) in Northwestern China.

The Eurasian lynx (Lynx) is a medium-sized wild cat species distributed throughout Eurasia. There has been no report on Taenia species (Cestoda: Cyclophyllidea) infecting this felid in China. In this study, 24 tapeworms were found in two Eurasian lynxes (#1 and #2) in Xinjiang Uygur Autonomous Region (XUAR), northwestern China. Based on the number, measurements and the shape of rostellar hooks, these tapeworms belong to two Taenia species. According to the number (n = 32) and length (185-194 µm) of small hooks, the first Taenia species (n = 1, found in #2 lynx) was identified as Taenia laticollis. Phylogenetically, this species was clustered with T. laticollis genotype C (JX860623) based on its cytochrome c oxidase subunit 1 (cox1) and 16S rDNA sequences. The second Taenia species (n = 23, provisionally named as "Taenia sp.") may represent a potentially novel tapeworm species, because of its obvious differences in the shape and lengths (174-182 µm, 98-113 µm) of large and small rostellar hooks in comparison with ten taxonomically related species. Molecular and phylogenetic analyses of the cox1 gene revealed that "Taenia sp." has the highest rate of sequence identity (92.93%, 368/396 bp) with Taenia hydatigena reported from sheep (Ovis aries) in Slovakia. To sum up, a potentially novel tapeworm species, "Taenia sp.", is found in Eurasian lynx. In addition, T. laticollis was found for the first time in China.

Assessment of the Genetic Diversity of Echinococcus multilocularis from Copro-Isolated Eggs.

The genetic diversity of the parasite Echinococcus multilocularis, the infectious agent of alveolar echinococcosis, is generally assessed on adult worms after fox necropsy. We aimed to investigate E. multilocularis polymorphism through the microsatellite EmsB marker using a noninvasive approach. We tested batches of isolated eggs (1, 5, and 10) from 19 carnivore fecal samples collected in a rural town located in a highly endemic area in France to determine the best strategy to adopt using a minimal quantity of parasite DNA while avoiding genetic profile overlapping in the analysis. Several molecular controls were performed to formally identify the Taeniidae eggs. In total, 112 egg batches were isolated and 102 EmsB electrophoregrams were obtained in duplicate. Quality sorting was performed through the Pearson correlation coefficient (r) between each EmsB duplicate. Forty-nine batches with r > 0.9 remained in the analysis, mainly 5- or 10-egg batches. Three EmsB profiles were emphasized by hierarchical clustering and matched those from human lesions and adult worms previously genotyped and collected in the same area. We show that the genetic diversity of the parasite can be assessed from isolated E. multilocularis eggs in a spatiotemporal context using a noninvasive approach.

[Progress of researches on serine protease inhibitors for zoonotic cestode family Taeniidae].

Serine protease inhibitor, a protein superfamily that inhibits the serine protease activity, protects hosts from parasitic infections. This review describes the spatial structure and classification of serine protease inhibitor, mechanisms underlying the interplay between serine protease inhibitor and host immune responses and current advances in serine protease inhibitor of zoonotic cestode family Taeniidae, so as to provide insights into the diagnosis of zoonotic tapeworm infections, discovery of therapeutic targets and screening of vaccine candidates.

Morphological and molecular analyses of Taenia and Mesocestoides species from red foxes (Vulpes vulpes) in northwestern China.

In this study, 263 tapeworms were collected from eight road-killed red foxes in Xinjiang Uygur Autonomous Region (XUAR, northwestern China). The tapeworms were analyzed based on morphological characters and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequences. Eighty-three Taenia and 180 Mesocestoides tapeworms were identified according to the presence or absence of rostellum, and the number, the length and the shape of the large rostellar hooks. The morphological and molecular analyses revealed that i) 180 Mesocestoides tapeworms, here named as Mesocestoides sp. (Vulpes vulpes), showed 99.21% (378/381 bp) identity to Mesocestoides sp. reported from red fox in Mongolia; and ii) 83 Taenia tapeworms belonged to three species. The first Taenia species [n = 16, named as Taenia sp. (Vulpes vulpes)], based on the length of large rostellar hooks (337-342 µm) and its cox1 sequence, was identified as a potentially novel species, which is phylogenetically close to Taenia laticollis. The second species [n = 54, named as Taenia sp. (Vulpes vulpes & Rhombomys opimus)], was morphologically similar to Taenia endothoracicus according to the number (n = 52), the length (319-332 µm) and the shape of the large rostellar hooks. This species, infecting three red foxes, shared 100% cox1 sequence identity with Taenia sp. (Rhombomys opimus) genotype C found previously in great gerbils (Rhombomys opimus) in the same region. The third species (n = 13, named as Taenia polyacantha-like), had shorter large rostellar hooks (178-180 µm) and showed 96.27% (361/375 bp) sequence identity to Taenia polyacantha reported from red fox in Italy. The "great gerbil-red fox" life cycle of Taenia sp. (Vulpes vulpes & Rhombomys opimus), belonging to the mitochondrial lineage of T. endothoracicus, is confirmed. The T. polyacantha-like species was firstly found in red fox in China. Taenia sp. (Vulpes vulpes) is a potentially novel species, which is close to T. laticollis based on its phylogenetic properties.