How tapeworms interact with cancers: a mini-review.

Cancer is one of the leading causes of death, with an estimated 19.3 million new cases and 10 million deaths worldwide in 2020 alone. Approximately 2.2 million cancer cases are attributed to infectious diseases, according to the World Health Organization (WHO). Despite the apparent involvement of some parasitic helminths (especially trematodes) in cancer induction, there are also records of the potential suppressive effects of helminth infections on cancer. Tapeworms such as Echinococcus granulosus, Taenia crassiceps, and more seem to have the potential to suppress malignant cell development, although in a few cases the evidence might be contradictory. Our review aims to summarize known epidemiological data on the cancer-helminth co-occurrence in the human population and the interactions of tapeworms with cancers, i.e., proven or hypothetical effects of tapeworms and their products on cancer cells in vivo (i.e., in experimental animals) or in vitro. The prospect of bioactive tapeworm molecules helping reduce the growth and metastasis of cancer is within the realm of future possibility, although extensive research is yet required due to certain concerns.

Suppression of the growth and metastasis of mouse melanoma by Taenia crassiceps and Mesocestoides corti tapeworms.

Cancer is still one of the leading causes of death, with an estimated 19.3 million new cases every year. Our paper presents the tumor-suppressing effect of Taenia crassiceps and Mesocestoides corti on B16F10 melanoma, the intraperitoneal application of which followed the experimental infection with these tapeworms, resulting in varying degrees of effectiveness in two strains of mice. In the case of M. corti-infected ICR mice, a strong tumor growth suppression occurred, which was accompanied by a significant reduction in the formation of distant metastases in the liver and lung. Tapeworm-infected C57BL/6J mice also showed a suppression of tumor growth and, in addition, the overall survival of infected C57BL/6J mice was significantly improved. Experiments with potential cross-reaction of melanoma and tapeworm antigens with respective specific antibodies, restimulation of spleen T cells, or the direct effect of tapeworm excretory-secretory products on melanoma cells in vitro could not explain the phenomenon. However, infections with T. crassiceps and M. corti increased the number of leukocytes possibly involved in anti-tumor immunity in the peritoneal cavity of both ICR and C57BL/6J mice. This study unveils the complex interplay between tapeworm infections, immune responses, and melanoma progression, emphasizing the need for further exploration of the mechanisms driving observed tumor-suppressive effects.

First report of apparent praziquantel resistance in Dipylidium caninum in Europe.

Dipylidium caninum is a common tapeworm of dogs. Two cases of praziquantel resistance have been described in D. caninum in the United States. No further reports have been published to the authors' knowledge. Here, the case of a dog imported to Switzerland from Spain with a history of chronic excretion of tapeworm proglottids and unresponsiveness to praziquantel treatments is reported. Clinical signs were mild (restlessness, tenesmus, anal pruritus, squashy feces) and flea infestation could be ruled out. Infection with D. caninum was confirmed through morphological and genetic parasite identification. Different subsequently applied anthelmintic compounds and protocols, including epsiprantel, did not confer the desired effects. Proglottid shedding only stopped after oral mebendazole administration of 86.2 mg kg−1 body weight for 5 consecutive days. Clinical signs resolved and the dog remained coproscopically negative during a follow-up period of 10 months after the last treatment. This case represents the first reported apparent praziquantel and epsiprantel resistance in D. caninum in Europe. Treatment was extremely challenging especially due to the limited availability of efficacious alternative compounds.

PALEOEPIDEMIOLOGY OF DIPHYLLOBOTHRIOSIS: CULTURAL AND ENVIRONMENTAL FACTORS AFFECTING ADENOCEPHALUS INTENSITY AND PREVALENCE.

Peruvian and Chilean mummies and coprolites provide a source of population-based parasitological information. This is especially true of the fish tapeworm, Adenocephalus pacificus. Our analysis of Chinchorro and Chiribaya mummies and diversified coprolite samples from Chile and Peru show variation in infection. There is a statistically significant difference in prevalence between Chinchorro hunter-gatherer and Chiribaya mixed-subsistence contexts. Furthermore, the most pronounced differences occur between populations within these groups. Chinchorro differences in cemeteries at the same location can be related to El Niño-Southern Oscillation variations. Pronounced prevalence variations between 3 Chiribaya villages within 7 km of each other relate to fish distribution and preparation variation. As with other recent archaeoparasitology studies, eggs-per-gram data exhibit overdispersion.

High Prevalence of Hymenolepis (Rodentolepis) nana in Amateur Breeding Facilities of Chinchillas (Chinchilla lanigera) and Sugar Gliders (Petaurus breviceps) from Italy.

PURPOSE: Hymenolepis (Rodentolepis) nana is an enteric tapeworm globally widespread in wild and captive rodents. The survey was carried out in three chinchilla breeding facilities and in one sugar glider breeding facility in Central and Southern Italy. METHODS: One hundred and four chinchilla fecal pools and 40 sugar glider fecal pools were collected from cages housing breeding pairs or females with their offspring. Fecal samples were examined with a qualitative and quantitative copromicroscopical approach. Hymenolepis eggs were identified based on morphological and morphometrical features, and the average number of eggs per gram (EPG) of feces was estimated. RESULTS: Hymenolepis nana eggs were detected in 39.42% of chinchilla samples with an average of 16.33 EPG; whereas, all of the sugar glider samples tested positive with an average of 454.18 EPG. Neither helminth eggs nor protozoan cysts/oocysts were detected in any of the breeding facilities. CONCLUSION: The results clearly show a diffuse parasitism in both chinchillas and sugar gliders, and should be taken into consideration given the rising popularity of these two pet species combined with the zoonotic complications presented by H. nana.

Anthelmintic efficacy of Holarrhena pubescens against Raillietina spp. of domestic fowl through ultrastructural, histochemical, biochemical and GLCM analysis.

Globally, traditional knowledge systems are a powerhouse of information which can revolutionise the world, if decoded accurately and logically. Plant-based ethno-traditional and folklore curatives/medicines has a firm basis in the psyche of the common masses of West Bengal and Holarrhena pubescens is a representative example of it. This article communication on depicting the anthelmintic efficacy of ethanolic extract and Ethyl acetate fraction of the stem bark of Holarrhena pubescens against the cestode Raillietina spp. through efficacy studies, ultra-structural observations, histochemical and biochemical analysis on some tegumental enzymes i.e., Acid Phosphatase (AcPase), Alkaline Phosphatase (AlkPase), Adenosine Triphosphatase (ATPase) and 5'-Nucleotidase (5'-Nu) along with Gray Level Co-occurrence Matrix (GLCM) analysis of histochemical study. Praziquantel was used as the reference drug. Investigations revealed 10mg/ml dosage of crude extract was the most efficacious dose and amongst the fractions the ethyl acetate fraction showed the most anthelmintic property. Ultrastructural studies through Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) clearly depicted the damage in head, sucker, proglottids, proximal and distal cytoplasm (DC), microtriches (MT), basal lamina (BL), nuclear membrane (NM), and, nucleolus (NL) in the treated worms. Histochemical studies revealed decrease in staining intensity for all the tegumental enzymes in the treated worms compared to control. The GLCM analysis strongly supported the result of histochemical studies. Biochemical studies revealed marked reduction in enzyme activity in the treated worms with maximum reduction in the activity of 5'- Nu (77.8%) followed by ATPase (63.17%).

First insights into the activity of major digestive enzymes in the intestine of the European catfish Silurus glanis and protective anti-enzymatic potential of its gut parasite Silurotaenia siluri.

The European catfish Silurus glanis is attracting growing interest as an object of fisheries and aquaculture, which is reinforced by the expansion of its natural range under climate change. Shaping the effective exploitation strategy for this valuable species requires detailed knowledge of its biology, including feeding and digestion processes, especially near the natural limits of the species range. Meanwhile, the digestion physiology of the European catfish remains poorly explored, including the activity of major digestive enzymes and the possible effect of intestinal parasites on this activity. In this regard, the activity of proteinases and α-amylase in the intestinal mucosa of the catfish was studied. Adult catfish were collected in the Rybinsk reservoir (Upper Volga) located close to the northern limit of the species range. It was shown that all subclasses of intestinal digestive proteinases, including serine proteinases, metalloproteases and cysteine (thiol) proteinases, function in the gut mucosa of the catfish. The mucosal levels of total proteolytic activity depended on fish size, in contrast to those of trypsin, chymotrypsin and α-amylase. The level of chymotrypsin activity was significantly higher than that of trypsin activity. It was also found that the incubation medium and extract of the cestodes Silurotaenia siluri parasitizing the catfish gut had a significant inhibitory effect on the activity of serine proteases (trypsin and chymotrypsin) operating in the intestines of the host fish.

ERECTION OF BOTHRIOCESTUS N. GEN. (CESTODA: BOTHRIOCEPHALIDEA) AND REDESCRIPTION OF BOTHRIOCESTUS CUSPIDATUS (COOPER, 1917) (SYN. BOTHRIOCEPHALUS CUSPIDATUS) FROM WALLEYE, SANDER VITREUS, (PERCIFORMES: PERCIDAE) IN NORTH AMERICA.

Based on previous molecular phylogenetic analyses, Bothriocestus n. gen. is erected to accommodate bothriocephalid tapeworms that have an elongate scolex, a well-developed apical disc, and a narrow neck region, parasitize freshwater fishes in the Holarctic, and were previously placed in the polyphyletic genus Bothriocephalus Rudolphi, 1808 (Cestoda: Bothriocephalidea). Bothriocestus claviceps (Goeze, 1782) n. comb., a parasite of eels (Anguilla spp.) in the Holarctic region, is designated as the type species. Another species of the new genus, Bothriocestus cuspidatus (Cooper, 1917) (syn. Bothriocephalus cuspidatusCooper, 1917) is redescribed from type and voucher specimens, and new material from the type host, the walleye, Sander vitreus (Mitchill, 1818) (Perciformes: Percidae), in Manitoba and Ontario (where the type locality is located) (Canada) and in New York state and Wisconsin. Bothriocestus cuspidatus of S. vitreus is characterized primarily by the possession of a narrow, long strobila (total length up to 18 cm) composed of distinctly craspedote, trapezoidal proglottids, with primary, secondary, and tertiary proglottids differing in size, and by an arrow-shaped (=cuspidatus) scolex that is distinctly broader than the first proglottids, widest near the base in lateral view and gradually becoming broader toward the anterior end in dorsoventral view. A "dwarf" form of B. cuspidatus (total length of 9-27 mm) from Johnny darter, Etheostoma nigrum Rafinesque, 1820, and tessellated darter, Etheostoma olmstedi Storer, 1842 (both Percidae: Etheostominae), is also characterized morphologically in the present paper.

Cryptic species Hydatigera kamiyai and other taeniid metacestodes in the populations of small mammals in Serbia.

BACKGROUND: Hydatigera (Cestoda: Taeniidae) is a recently resurrected genus with the description of a new species, Hydatigera kamiyai, a cryptic entity within the Hydatigera taeniaeformis species complex. Rodents are intermediate hosts and correct taxonomic identification of H. taeniaeformis sensu lato (s.l.) species is difficult without the use of molecular methods. The aim of this study was to identify and explore the genetic diversity of Hydatigera and other taeniid species. METHODS: Ten different small mammals species (856 individuals) (Rattus rattus, three Apodemus, three Arvicolinae and three Soricidae species) were examined from 2013 to 2023. Captured animals were visually examined for cysts and visible lesions. Two markers were used for amplification and sequencing: cox1 and 12S rDNA. RESULTS: Molecular analysis of cysts and visible lesions revealed four taeniid species: Hydatigera kamiyai, H. taeniaeformis sensu stricto (s.s.), Taenia martis and T. crassiceps. Hydatigera kamiyai was found in Apodemus flavicollis, A. agrarius, Microtus arvalis and Crocidrua leucodon, while H. taeniaeformis s.s. is registered in R. rattus. Hydatigera kamiyai cox1 sequences clustered with European populations and showed at least 25 nucleotid differences compared to Asian, African, Australian and one of our isolates of H. taeniaeformis s.s acquired from a rat, followed by large sequence distances (9.4% to 12.9%), indicating clear molecular distinction of two species. CONCLUSIONS: This is one of the few mitochondrial gene-based studies performed after the description of cryptic entities within the Hydatigera taeniaeformis s.l. complex and represents a valuable contribution to understanding of genetic diversity, host suitability and geographic distribution of these tapeworm species. Also, our study provides an important basis of molecular data from this part of Europe for further studies. We emphasize the importance of additional studies of intermediate hosts, especially rats from Europe and Apodemus spp. and voles from Asia and Africa.

Squamata reptiles as a potential source of helminth infections when preyed on by companion animals.

BACKGROUND: Squamate reptiles cohabiting with companion animals may represent a source of helminth infections, especially through predation by dogs and cats with an outdoor lifestyle. METHODS: In order to assess the role of reptiles as intermediate/paratenic hosts of trophically transmitted helminths, synanthropic reptiles (n = 245) captured from different ecological settings (i.e., households, dog shelters, urban, peri-urban and rural areas or natural parks) of southern Italy were examined for endoparasites. Parasitic cysts (i.e., larval forms of acanthocephalans, cestodes and nematodes) and free helminths (i.e., adult nematodes and digeneans) were morphologically and molecularly identified, and statistical analysis was carried out to evaluate the correlations between reptiles, infections, and ecological settings. RESULTS: Overall, 31% of reptiles were positive for at least one helminth, with Podarcis siculus (18.7%) and Tarentola mauritanica (8.1%) being the most frequently infected species. Among the parasites of medical interest, Joyeuxiella echinorhyncoides showed the highest prevalence (19.7%), followed by Diplopylidium acanthotetra (10.5%), Joyeuxiella pasqualei, Mesocestoides lineatus (5.6%) and Physaloptera sp. (3.9%). Macracanthorhynchus hirudinaceus was detected once. Podarcis siculus and T. mauritanica were associated with cestode infections. CONCLUSIONS: The wide range of helminths detected here in reptiles living in sympatry with pets and the fact that many of these helminth species are parasitic and may infect companion animals (e.g., J. pasqualei, J. echinorhyncoides, D. acanthotetra, Physaloptera sp.) and humans (i.e., Macracanthorhynchus hirudinaceus, Mesocestoides lineatus) indicate the potential health risk associated with pets preying on these small vertebrates. Our results indicate the need for complementary investigations of trophically transmitted parasites in dogs and cats living in sympatry with reptiles.

Identification of wild rodents as intermediate hosts for Hydatigera taeniaeformis in Peru.

Hydatigera taeniaeformis is a cestode that uses felines and rodents as definitive and intermediate hosts, respectively. Its larval stage, or metacestode, infects a wide variety of rodent species and develops in the liver parenchyma into a cyst. The aim of this study was to evaluate the occurrence of H. taeniaeformis metacestode in various species of wild rodents from Peru. For this, the livers of 356 rodents were macroscopically examined for any parasitic form compatible with metacestodes. Metacestodes were identified by measuring characteristic morphological parameters, and the diagnosis was confirmed by molecular analysis of a fragment of the cytochrome c oxidase subunit 1 gene (cox1). Five rodents: two small-eared pygmy rice rats (Oligoryzomys microtis), two white-naped squirrels (Simosciurus nebouxii), and one pygmy rice rat (Oligoryzomys sp.) were infected with H. taeniaeformis metacestodes. The cox1 sequences from our metacestodes showed up to 100% identity with previous H. taeniaeformis sequences from the GenBank. These results demonstrated the occurrence of H. taeniaeformis in new intermediate hosts, as well as the first molecular contribution for H. taeniaeformis from Peru.

Apparent treatment failure of praziquantel and pyrantel pamoate against anoplocephalid tapeworms.

Anoplocephalid tapeworms are commonly occurring in grazing horses around the world. Two currently available anthelmintics have documented high efficacy against Anoplocephala perfoliata; praziquantel in various dosages ranging from 1.0 to 2.5 mg/kg and pyrantel pamoate administered at 13.2 mg base/kg. Anthelmintic resistance has not been reported in A. perfoliata, but anecdotal reports made during 2022 have suggested a possible loss of efficacy for both actives. This paper reports fecal egg count data from a Thoroughbred operation in Central Kentucky in 2023. Fifty-six yearlings were first dewormed with a combination of ivermectin (200 µg/kg) and praziquantel (1.5 mg/kg) and subsequently treated with pyrantel pamoate (13.2 mg base/kg). Fecal egg counts were determined at the day of treatment and again 14 days post-treatment. Two groups of mares (n = 39 and 45) were also treated with ivermectin/praziquantel and examined pre- and post-treatment. Low efficacy of ivermectin and pyrantel pamoate was demonstrated against strongylid parasites in the yearlings with mean Fecal Egg Count Reductions (FECRs) at 75.6% or below and upper 95% credible interval (CI) limits below 90% in all cases. Overall anti-cestodal FECR levels in the yearlings were 23.5% (95% CI: 11.2-48.0) for praziquantel and 50.9% (20.5-72.0) for pyrantel pamoate. Praziquantel eliminated anoplocephalid eggs from three of 17 yearlings, but another 5 yearlings went from negative to positive status following treatment. Pyrantel pamoate failed to eliminate anoplocephalid eggs from any of 14 treated tapeworm-positive yearlings. Nine of 84 mares tested positive for anoplocephalid eggs, and seven of these were still positive post praziquantel treatment. These findings sharply contrast data from historic field efficacy studies conducted for both actives and raise concern about anthelmintic resistance having possibly developed. This emphasizes the need for developing and refining antemortem methodologies for evaluating anti-cestodal treatment efficacy and for searching for possible alternative treatment options.

Phylogenetic relationships, host associations, and three new species of a poorly known group of "tetraphyllidean" tapeworms from elasmobranchs.

This paper aims to expand understanding of a poorly known group of cestodes that parasitize an intriguingly diverse suite of elasmobranchs. The group's three currently described members (i.e., Pentaloculum macrocephalum, Pentaloculum hoi, and Zyxibothrium kamienae) parasitize an electric ray, a carpet shark, and a skate, respectively. Pentaloculum grahami n. sp. is described from a second genus of carpet shark, specifically Parascyllium collare, in Australia. Zyxibothrium duffyi n. sp. and Zyxibothrium healyae n. sp. are described from the deep-sea skates Brochiraja asperula and Brochiraja spinifera, respectively off New Zealand. The three new species share distinctive bothridia that bear a small number of large, circular, facial loculi and lateral bands of vitelline follicles that converge posterior to the ovary-features which are found in all other members of these genera. Zyxibothrium healyae n. sp. is unique in possessing three, rather than four or five, facial loculi. Zyxibothrium duffyi n. sp. possesses a combination of five facial loculi and vitelline follicles that stop short of the anterior margin of the proglottid. Pentaloculum grahami n. sp. is the largest member of the group with the greatest number of proglottids. Based on striking similarities in scolex morphology, Pentaloculum and Zyxibothrium have been hypothesized to belong to a distinct subgroup of "tetraphyllideans" provisionally designated as Clade 1. Based on sequence data for the D1-D3 region of the 28S rDNA gene generated for species of Zyxibothrium for the first time, we confirm the reciprocal monophyly of both genera as well as the monophyly of Clade 1 and its status as a distinct lineage among the "Tetraphyllidea". This work also suggests that the presence of five facial loculi is homoplasious given this character state is found in members of both genera. The new species expand the host associations of Clade 1 to include additional skate and carpet shark genera. Moving forward we would expect to find additional members of this group parasitizing other species of parascyliid carpet sharks as well as other species of the rajid genus Malacoraja and the arhynchobatid genus Brochiraja. Here we have doubled the number of described species in the taxon referred to as Clade 1 while simultaneously expanding our understanding of the morphology and anatomy of its members. This additional information will help inform the ultimate revision of the ordinal classification of the cestodes to address the highly polyphyletic nature of the order "Tetraphyllidea" as it is currently configured.

Natural life cycle of Versteria cuja (Taeniidae) in Argentina and histopathology of metacestodiasis in intermediate hosts.

Using morphological and molecular studies, the life cycle of Versteria cuja (Cestoda: Taeniidae) was elucidated, involving subterranean rodents (Ctenomyidae) as intermediate hosts, and the lesser grison, Galictis cuja (Mustelidae), as definitive host. Metacestodes (cysticerci and polycephalic larvae) were found mainly in the liver but also in spleen, pancreas, lungs and small intestine of 2 species of tuco-tucos (Ctenomys spp.) from Chubut, Argentina. Identity of the metacestodes with the adult was based primarily on the number, size and shape of rostellar hooks: 40­48 hooks in 2 rows, particularly small (10­16 µm total length by 6­10 µm wide), composed of handle, blade and guard with characteristic shapes. Genetic analysis (cox1 gen mtDNA) performed on metacestodes from both intermediate hosts corroborated their conspecificity with adults of V. cuja from lesser grisons in the same locality. Histopathological study showed the hepatic parenchyma altered by the presence of cysts containing larvae, each surrounded by a capsule of connective tissue with inflammatory infiltrate, atrophied hepatocytes and an increase of bile ducts. In the lung, in addition to the cysts, dilated alveoli, oedema and hyperaemic blood vessels were observed. This is the first report of a natural life cycle of a Versteria species from South America. It shows strong similarities with that described for a North American zoonotic lineage of Versteria, confirming a close relationship between V. cuja and this North American lineage, as previously demonstrated by molecular studies. Consequently, the zoonotic potential of V. cuja should not be disregarded.

Natural variation in the binding pocket of a parasitic flatworm TRPM channel resolves the basis for praziquantel sensitivity.

The drug praziquantel (PZQ) is the key clinical therapy for treating schistosomiasis and other infections caused by parasitic flatworms. A schistosome target for PZQ was recently identified- a transient receptor potential ion channel in the melastatin subfamily (TRPMPZQ)-however, little is known about the properties of TRPMPZQ in other parasitic flatworms. Here, TRPMPZQ orthologs were scrutinized from all currently available parasitic flatworm genomes. TRPMPZQ is present in all parasitic flatworms, and the consensus PZQ binding site was well conserved. Functional profiling of trematode, cestode, and a free-living flatworm TRPMPZQ ortholog revealed differing sensitives (~300-fold) of these TRPMPZQ channels toward PZQ, which matched the varied sensitivities of these different flatworms to PZQ. Three loci of variation were defined across the parasitic flatworm TRPMPZQ pocketome with the identity of an acidic residue in the TRP domain acting as a gatekeeper residue impacting PZQ residency within the TRPMPZQ ligand binding pocket. In trematodes and cyclophyllidean cestodes, which display high sensitivity to PZQ, this TRP domain residue is an aspartic acid which is permissive for potent activation by PZQ. However, the presence of a glutamic acid residue found in other parasitic and free-living flatworm TRPMPZQ was associated with lower sensitivity to PZQ. The definition of these different binding pocket architectures explains why PZQ shows high therapeutic effectiveness against specific fluke and tapeworm infections and will help the development of better tailored therapies toward other parasitic infections of humans, livestock, and fish.

Confocal laser scanning microscopy (CLSM) as a new tool for morphological characterisation of both newly collected and museum voucher specimens of the Trypanorhyncha Diesing, 1863 (Platyhelminthes: Cestoda).

Taxonomic issues within Trypanorhyncha, e.g., the inaccurate light microscopic visualisation of the hook patterns, are solvable by confocal laser scanning microscopy (CLSM). We applied CLSM imaging to study Trygonicola macropora (Shipley et Hornell, 1906) and Dollfusiella michiae (Southwell, 1929) from Neotrygon caeruliopunctata Last, White et Séret from Bali, Indonesia. To illustrate the strength and limitations of CLSM, images of Otobothrium cysticum (Mayer, 1842) and Symbothriorhynchus tigaminacantha Palm, 2004, both permanent mounts from a collection, were also processed. The CLSM created image stacks of many layers, and edited with IMARIS Software, these layers resulted in three-dimensional images of the armature patterns and internal organs of both species. BABB (benzylalcohol and benzylbenzuolate) clearing was applied to T. macropora. We conclude that trypanorhynch cestodes stained with Mayer-Schuberg's acetic carmine permanently mounted in Canada balsam are suitable for CLSM, allowing detailed analyses of museum type-material as well as freshly collected and processed worms. BABB resulted in imaging the testes in detail, suggesting other stains to be used for CLSM in trypanorhynch cestode research. Application of CLSM for studies of other cestode groups is highly recommended.

Morphological and molecular characterization of the parasite Dipylidium caninum infecting an infant in Colombia: a case report.

BACKGROUND: Dipylidium caninum is the causal agent of dipylidiasis affecting mainly cats and dogs worldwide. Human cases of dipylidiasis are rare, and the diagnosis is prevalently based on morphological features of the parasite. Here we report the diagnosis of dipylidiasis through morphological and molecular characterization of D. caninum infecting an 11-month-old boy in Cajicá, Colombia. METHODS: Fresh faecal samples were obtained from the infant, and morphological identification of the parasite was performed through faecal smears. DNA was extracted from proglottids and used in PCR analyses for amplification of a 653-bp fragment of the nuclear ribosomal RNA (rRNA) encoding the 28S rRNA gene. A phylogeny study to better characterize the obtained DNA sequence was inferred using the maximum likelihood method and the Tamura-Nei model. RESULTS: After morphological and molecular analyses, D. caninum was identified as the etiological agent causing the infection in the infant. Results of phylogenetical analyses showed that the obtained sequence clusters within the feline genotype clade. After the diagnosis of the parasite, effective treatment with praziquantel was administered to the infant. CONCLUSIONS: This is the third human case of dipylidiasis reported in Colombia, and the first study in South America to provide a molecular identification of D. caninum.

Elimination of probable praziquantel-resistant Dipylidium caninum with nitroscanate in a mixed-breed dog: a case report.

BACKGROUND: Praziquantel is the drug of choice for treating the tapeworm Dipylidium caninum in dogs; however, resistance is possible, and regular, non-targeted administration of praziquantel may select for anthelminthic-resistant populations. METHODS: The zinc sulfate fecal floatation procedure was conducted. Gross visualization was used to identify Dipylidium spp. segments, and capsule endoscopy was used to visualize adult tapeworms within the intestinal tract. RESULTS: An 18-month-old spayed female terrier mix was presented due to diarrhea, hematochezia and weight loss. The dog received appropriate anthelmintic therapy for Giardia spp., Ancylostoma spp. and Dipylidium spp. The dog's clinical signs resolved, and elimination of Ancylostoma spp. was confirmed by subsequent fecal analysis. However, Dipylidium spp. segments were repeatedly present in the stool. Observation of the segments confirmed the presence of adult Dipylidium spp in feces. Treatment with praziquantel and epsiprantel were unsuccessful in eliminating the organism but was apparently successful in flea prevention. A single dose of nitrosconate was administered and eliminated Dipylidium spp. infection in the dog. CONCLUSIONS: Nitrosconate can be an effective treatment for praziquantel-resistant dipylidiasis in dogs. The novel application of capsule endoscopy confirmed the anthelmintic efficacy of this treatment.

First Report on Molecular Identification of Moniezia expansa in Sheep from Mannavanur, Palani Hills, Tamil Nadu, India.

PURPOSE: Tape worm infection is common among sheep at SRRC, Mannavanur, Palani hills, Tamil Nadu, India. The aim of the present study is to find out the cestode species infecting the sheep being maintained at SRRC, Mannavanur, by means of molecular method. METHODS: During the second week of June 2021, the hogget flock of sheep (comprising both Bharat Merino and Avikalin sheep breeds) was drenched on empty stomach with commercial preparation of anthelmintic drug containing Niclosamide plus Albendazole, as per the standard dose specified by the manufacturer (Niclozole™: each 5 ml contains 500 mg of Niclosamide and 150 mg of Albendazole: dose for sheep-10 ml/15 kg body weight). The tapeworms expelled in dung by the drug-treated sheep were collected, washed in PBS (pH 7.2), and fixed in between two glass slides using 10% formalin. Furthermore, cytochrome c oxidase subunit I (Cox-I) gene-based PCR was carried out. Only partial sequence (1593 bp) of Cox-I gene of Moniezia expansa from Sheep at SRRC, Mannavanur, Tamil Nadu, India was obtained by PCR. The PCR amplified fragment was cloned into pGEM-T vector and the recombinant plasmid was sequenced. The obtained nucleotide sequences of Cox-I gene of the M. expansa from Indian sheep were analysed with that of 27 more cestode species from different mammalian species (available in GenBank) using bioinformatics tools. RESULTS: The species of the tapeworm was identified as Moniezia species by the Department of Veterinary Parasitology, VC& RI, Orathanadu, TANUVAS by the standard Acidic alum carmine staining method. Due to the ambiguity in the conventional method, Cox-I gene-based PCR and subsequent gene sequencing protocols were used for the identification of the species of cestode infecting sheep at SRRC, Mannavanur, and it was confirmed as M. expansa upon BLAST analysis. Moniezia expansa from SRRC, Mannavanur is having 100% sequence identity at nucleotide level with that of M. expansa from Sengal/Ethiopia. M. benedeni shared 87-88% nucleotide identity with Indian M. expansa. With taenids, the share of percent nucleotide identity of Indian M. expansa ranged from 79 to 81%. M. expansa from Indian sheep was clustering with other anaplocephalids from various mammalian species in the analysis of phylogenetic tree based on Cox-I nucleotide sequences. CONCLUSION: From the present study, it is concluded that M. expansa is the anoplocephalid cestode infecting the sheep at Mannavanur, Tamil Nadu, India. To our knowledge, this is the first report on partial nucleotide sequences of Cox-I gene of M. expansa from Sheep of Indian peninsula. An investigation on the involvement of oribatid mites as the vector in the transmission of M. expansa among sheep at SRRC, Mannavanur needs to be carried out.