Toxascaris leonina in dogs - A nematode species of high prevalence in some regions of Eurasia.

A recent meta-analysis of studies from around the world had shown a global prevalence of Toxascaris leonina in stray dogs of about 7%. However, studies from Eurasian regions, where higher percentages of positive dogs were often found, were under-represented in this meta-analysis. This prompted the present study. Its main objective was to examine free-roaming dogs from the capital city of Kazakhstan to obtain information on the current occurrence of T. leonina egg shedding compared to Toxocara spp. Faecal samples from 500 free-roaming dogs from the city of Astana and its suburbs were collected 1-2 days after admission to the municipal animal shelter during three time periods (May to October 2019, September 2020, and April 2021). Samples were examined by a saline flotation method. Nematode egg-positive samples were subjected to a modified McMaster method to determine the number of eggs per gram of faeces (EPG). Toxascaris leonina eggs were found in 53.8% and Toxocara spp. eggs in 14.8% of the dogs examined. The prevalence of T. leonina egg shedding was significantly associated with age class but not with sex: dogs aged between 6 months and 2 years were more likely to be T. leonina egg positive than puppies. The intensity of T. leonina egg shedding was also age dependent: dogs aged between 6 months and 2 years had significantly higher EPGs compared to younger or older animals. In contrast, the prevalence of Toxocara spp. egg shedding was associated with both age class and sex: dogs older than 2 years were less likely to shed Toxocara spp. eggs than puppies, and females were less likely to be Toxocara spp. egg positive compared to males. The present results confirm those of other studies in Eurasian regions. It is therefore reasonable to assume that the global prevalence of T. leonina infection has been underestimated and should be revised accordingly.

Structural basis for T cell immunoglobulin and mucin protein 3 and Toxascaris leonina galectin complex.

T-cell immunoglobulin and mucin protein 3 (Tim-3), also known as Hepatitis A virus cellular receptor 2, has been discovered to have a negative regulatory effect on murine T-cell responses. Galectin-9 exhibits various biological effects, including cell aggregation, eosinophil chemoattraction, activation, and apoptosis, observed in murine thymocytes, T-cells, and human melanoma cells. Such approach demonstrated that Galectin-9 acts as a binding partner on Tim-3 and mediates the T-cell inhibitory effects. Tl-gal is a homologous protein to galectin-9, isolated from the adult stage of the canine gastrointestinal nematode parasite Toxascaris leonina. However, molecular mechanism between Tim-3 and galectin-9 is still remain unknown. Here, we describe the cryo-electron microscopy and X-ray structures and interactions of the Tim-3 and Tl-gal complex as well as their biochemical and biophysical characterization. In the structure, Ser46 residue of Tl-gal NCRD was bound to Asp25 residue of hTim-3. Compared to our previous study, the binding site of the complex is the same as the sugar binding site (the Ser46 residue) of Tl-gal. In addition, analysis of the complex structure revealed that the four Tl-gal molecules were in an open form packing and one mTim-3 peptide was bound to one Tl-gal molecule. These observations suggest that how Tl-gal binds hTim3 is essential to understanding the molecular mechanism for the Tim-3-galectin 9 interaction that regulates immune responses. This could potentially serve as a therapeutic target for inflammatory diseases.

[Genetic variation of sequences of partial mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit 1 (pnad1) and pnad5 genes of Toxascaris leonina isolates from foxes and dogs in Jiuquan City of Gansu Province].

OBJECTIVE: To investigate the genetic variations of Toxascaris leonina isolates from different hosts in Jiuquan City, Gansu Province. METHODS: The mitochondrial sequences of partial mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit 1 (pnad1) and pnad5 of eleven T. leonina isolates from domestic dogs, foxes and pet dogs in Jiuquan City, Gansu Province, were amplified using PCR, and the amplification product was sequenced. The genetic variations of pnad1 and pnad5 genes in T. leonina isolates were analyzed. RESULTS: The sequences of T. leonina pnad1 and pnad5 genes measured 530 bp and 550 bp in size, respectively. The nucleotide sequence homology was 99.4% to 100.0% for T. leonina pnad1 gene and 99.5% to 99.8% for T. leonina pnad5 gene, and the sequences of T. leonina pnad1 and pnad5 genes shared 99.2% to 99.9% and 99.1% to 99.9% with corresponding sequences of known T. leonina isolates. In addition, there were 19 and 24 polymorphic sites detected in the sequences of T. leonina pnad1 and pnad5 genes, with 10 and 9 haplotypes, haplotype diversity of 0.982 and 0.964 and nucleotide diversity of 0.039 4 and 0.034 2, respectively. Phylogenetic analysis based on pnad1 and pnad5 gene sequences showed that the eleven T. leonina isolates and known T. leonina isolates were clustered into the same branch with a random distribution, which were close to the branch where Toxocara canis was clustered, and far from the branch where other Ascaris species were clustered. CONCLUSIONS: There is a minor genetic variation in pnad1 and pnad5 genes of T. leonina isolates from different hosts in Jiuquan City, Gansu Province, and the pnad1 gene is more suitable as a molecular marker than pnad5 gene for analysis of genetic variations in T. leonina.

A five-year retrospective study on ascarid infections in dogs in southern Italy.

INTRODUCTION: A 5-year retrospective analysis of ascarid infections (Toxocara canis and Toxascaris leonina) in dogs from southern Italy was performed to update the epidemiological scenario of these parasites and to identify the risk factors which may favour these infections in animals in this study area. A total of 8,149 dogs, referred to our labs for copromicroscopic analysis using the FLOTAC technique, was considered. A sub-sample of 500 faecal samples were analysed also with the Mini-FLOTAC technique. Of the overall dog samples analysed, 9,2 % (95 % CI = 8,6-9,8) resulted positive for T. canis while 0,5 % (95 % CI = 0,4-0,7) resulted positive for T. leonina. Co-infections with T. canis and T. leonina were found in 0,1 % of dogs (95 % CI = 0,0-0,1). The results obtained by the FLOTAC and Mini-FLOTAC examinations showed a nearly perfect k agreement (k = 0,99, P < 0,001) between these two techniques. Chi-square test showed positivity to T. canis and T. leonina significantly (P < 0,001) associated with dogs housed outdoor (i.e., that lived in garden or in kennel). Moreover, the positivity for T. canis was significantly associated (P < 0,001) also with age (i.e., puppies), as shown by the logistic regression. The decreasing overall prevalence both for T. canis and T. leonina during the years of monitoring, showed that, as suggested by the European Scientific Counsel Companion Animal Parasites, the regular diagnosis could contribute to an efficient control of these parasites.

INTRODUCTION: Une analyse rétrospective sur 5 ans des infections à ascaris (Toxocara canis et Toxascaris leonina) chez les chiens du sud de l'Italie a été réalisée afin de mettre à jour le scénario épidémiologique de ces parasites et d'identifier les facteurs de risque pouvant favoriser ces infections chez les animaux de cette zone d'étude. Au total, 8149 chiens ont été analysés dans notre laboratoire avec une analyse copromicroscopique en utilisant la technique FLOTAC. De plus, un sous-échantillon de 500 échantillons fécaux a été analysé avec la technique Mini-FLOTAC. Sur l'ensemble des échantillons fécaux canins analysés, 9,2 % (IC à 95 % = 8,6 à 9,8) se sont révélés positifs pour T. canis tandis que 0,5 % (IC à 95 % = 0,4 à 0,7) ont été positifs pour T. leonina. Des co-infections avec T. canis et T. leonina ont été trouvées chez 0,1 % des chiens (IC à 95 % = 0,0­0,1). Les résultats obtenus par les examens FLOTAC et Mini-FLOTAC ont montré un coefficient Kappa presque parfait (k = 0,99, p < 0,001) entre ces deux techniques. Le test du chi carré a montré une positivité significative quant aux infections à T. canis et T. leonina (P < 0,001) associées à des chiens hébergés à l'extérieur (jardin ou chenil). De plus, la positivité pour T. canis était également significativement associée (P < 0,001) à l'âge (c'est-à-dire aux chiots), comme le montre la régression logistique. La diminution de la prévalence globale au cours de la période de surveillance a montré que le diagnostic régulier pourrait contribuer à un contrôle efficace de ces parasites à la fois pour T. canis et T. leonina, comme suggéré par le the European Scientific Counsel Companion Animal Parasites.

First report on occurrence of zoonotic helminth Toxocara canis, Toxascaris leonina and Ancylostoma caninum in domestic dogs from province of Djelfa, Algeria.

A total of 85 faecal samples of domestic dogs were collected from six localities, including Birine, Sidi Ladjel, Dar Chioukh, Aïn Maâbed, Aïn El-Ibel and Djelfa city from province of Djelfa, Algeria. Samples were tested for presence of Toxocara canis, Toxascaris leonina and Ancylostoma caninum eggs by formol-ether concentration and flotation techniques. Microscopic examination revealed an infection rate of 9.4%, 15.3% and 1.15% for T. canis, T. leonina and A. caninum, respectively. Males were more frequently infected with T. leonina as compared to females, while, no difference was observed regarding T. canis and A. caninum. Prevalence of T. canis and T. leonina did not vary significantly with age ranges of dogs. In contrast, A. caninum seems to be more found in dogs aged of 6-12 months. Prevalence of the three species did not vary significantly in dogs without diarrhea and those with diarrhea. Through these preliminary findings, dogs from steppic region of Djelfa can play a potential role in the dissemination of these neglected zoonotic helminths, which may endanger health of peoples, particularly, pastoral community.

A 3-year retrospective analysis of canine intestinal parasites: fecal testing positivity by age, U.S. geographical region and reason for veterinary visit.

BACKGROUND: Canine life stage is a key factor in parasite prevalence as clinical signs associated with parasitism are more common in pups. In adult dogs, health status and geographical region may also play a role in parasite prevalence. The purpose of this study was to evaluate fecal test results using zinc sulfate flotation by centrifugation combined with fecal antigen testing for hookworms (Ancylostoma spp. Uncinaria stenocephala), ascarids (Toxocara canis, Toxascaris spp., Baylisascaris spp.) and whipworms (Trichuris vulpis) sorted by age, geographical region and veterinary visit type. METHODS: A retrospective sample of intestinal parasite panels submitted to IDEXX Laboratories from 1,626,104 individual dogs were selected from the continental USA from 1 January 2017 to 31 December 2019. These data contain results from fecal exams performed using zinc sulfate flotation by centrifugation paired with coproantigen immunoassay results for hookworms, ascarids, whipworms and Giardia (Fecal Dx® with Giardia coproantigen immunoassay plate). For paired testing, if either the coproantigen assay or flotation test was positive, the sample was considered to be positive. Data were summarized by age category, U.S. Census Bureau geographical region (Northeast, South, Midwest, West) and veterinary visit type. Visit types were subdivided into Wellness Visits and Other Clinical Visits in which a fecal sample was submitted. RESULTS: In dogs presenting for either Wellness Visits or Other Clinical Visits in which Giardia testing was included, Giardia had the highest positivity (combined results for microscopy and coproantigen: 12.2 and 10.8%, respectively), followed by hookworms (combined microscopy and coproantigen: 4.1 and 4.2%, respectively), ascarids (combined microscopy and coproantigen: 2.5 and 1.7%, respectively) and whipworms (combined microscopy and coproantigen: 1.1 and 1.4%, respectively). When all test results were pooled together, pups aged 2-6 months were observed to have the highest proportion of positive results by either microscopy or coproantigen immunoassay regardless of clinical visit type. Parasite positivity varied by geographical region. Regardless of visit type, age or geographical region, the coproantigen method was observed to find a higher proportion of positive test results than microscopy in Giardia, ascarids, hookworms and whipworms. CONCLUSIONS: The Fecal Dx® coproantigen immunoassay combined with the zinc sulfate flotation by centrifugation method uncovers a higher number of positive hookworm, ascarid and whipworm infections than zinc sulfate flotation alone in both pups and adult dogs across all geographical regions of the USA regardless of visit type.

Detection and molecular characterisation of intestinal parasites in the South China tiger Panthera tigris amoyensis (Hilzheimer).

Parasitic infections of the South China tigers in the Meihua Mountains have not been explored previously. Faeces of 22 South China tigers from the China Tiger Park in the Meihua Mountains were examined. Eggs of ascaridoid nematodes and oocysts of coccidia were detected by Mini-FLOTAC assay. Morphological observation and molecular characterisation of the oocysts were carried out. The prevalence of Toxascaris leonina (von Linstow, 1902) was 18% (4/22), and the highest egg per gram (EPG) count in the faeces was 27,150. The prevalence of Cystoisospora sp. was 45% (1 0/22) and the highest oocysts per gram (OPG) in the faeces was 6,000. In addition, we found one ascaridoid nematode in the South China tiger's faeces and was molecularly and morphologically identified as T. leonina. The oocysts in the faeces were sporulated in vitro and identified as Cystoisospora sp. Amplification of full-length internal transcribed spacers (ITS) resulted in sequences 1,622 bp long. Using the sequences, Cystoisospora sp. of the South China tiger was closest to Isospora belli (Wenyon, 1923) and Cystoisospora suis (Biester, 1934).

Molecular characterization of ascaridoid parasites from captive wild carnivores in China using ribosomal and mitochondrial sequences.

BACKGROUND: Despite the public health importance of toxocariasis/toxascariasis, only a few species of these ascaridoid parasites from wild canine and feline carnivores have been studied at the molecular level so far. Poor understanding of diversity, host distribution and the potential (zoonotic) transmission of the ascaridoid species among wild animals negatively affects their surveillance and control in natural settings. In this study, we updated previous knowledge by profiling the genetic diversity and phylogenetic relationships of ascaridoid species among eleven wild canine and feline animals on the basis of a combined analysis of the ribosomal internal transcribed spacer region (ITS) gene and the partial mitochondrial cytochrome c oxidase subunit 2 (cox2) and NADH dehydrogenase subunit 1 (nad1) genes. RESULTS: In total, three genetically distinct ascaridoid lineages were determined to be present among these wild carnivores sampled, including Toxocara canis in Alopex lagopus and Vulpes vulpes, Toxocara cati in Felis chaus, Prionailurus bengalensis and Catopuma temmincki and Toxascaris leonina in Canis lupus, Panthera tigris altaica, Panthera tigris amoyensis, Panthera tigris tigris, Panthera leo and Lynx lynx. Furthermore, it was evident that T. leonina lineage split into three well-supported subclades depending on their host species, i.e. wild felids, dogs and wolves and foxes, based on integrated genetic and phylogenetic evidence, supporting that a complex of T. leonina other than one species infecting these hosts. CONCLUSIONS: These results provide new molecular insights into classification, phylogenetic relationships and epidemiological importance of ascaridoids from wild canids and felids and also highlight the complex of the taxonomy and genetics of Toxascaris in their wild and domestic carnivorous hosts.

Phylogenetic relationships among Toxocara spp. and Toxascaris sp. from different regions of the world.

Toxocara and Toxascaris are parasitic nematodes that infect canids and felids although species of the genus Toxocara also infect humans. This work aimed to establish the phylogenetic and phylogeographic relationship between specimens of T. canis, T. cati, T. malaysiensis and Toxascaris leonina and to evaluate the degree of host specificity. In total, 437 samples (adults and pools of eggs) were collected from canids and felids from eight countries. Parasites were identified by morphology, PCR linked Restriction Fragment Length Polymorphism (PCR-RFLP) and partial sequencing of the mitochondrial gene cox1. Phylogenetic trees were constructed and genetic distance among isolates was estimated. Based on the molecular characterization all worms were identified in agreement with their respective hosts with the exception of three samples; two from cats and one from dogs identified as T. canis and T. cati, respectively. There was no clear geographical clustering of the samples despite this study including parasites from three continents. This is the first study, to our knowledge, to use molecular methods to identify T. canis in cats and T. cati in dogs with host specificity being the most common finding. Our developed PCR-RFLP method was found to be a facile and reliable method for identifying Toxocara species.

Efficacy of a new oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against induced ascarid infections in dogs.

BACKGROUND: Ascarid infections are among the most prevalent intestinal parasitic infections occurring in dogs around the world, with Toxocara canis and Toxascaris leonina commonly observed. Toxocara canis can cause considerable disease in dogs and humans, and year-round prophylactic treatment and control in dogs is recommended. Elimination of immature stages of these parasites before egg-laying will reduce environmental contamination and the risk of infection for both dogs and humans. Studies were conducted to evaluate the efficacy of a novel, oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against induced immature adult (L5) and adult T. canis, and adult T. leonina infections in dogs. METHODS: Six negative-controlled, masked, randomized laboratory studies were conducted. Two studies each evaluated efficacy against immature adult (L5) T. canis, adult T. canis, and adult T. leonina. Sixteen to 40 dogs were included in each study. Dogs experimentally infected with the target parasite were dosed once on Day 0 with either placebo tablets or Simparica Trio™ tablets to provide minimum dosages of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5.0 mg/kg pyrantel (as pamoate salt). Efficacy was based on the number of worms recovered at necropsy 7-10 days after treatment compared to placebo control. RESULTS: Based on geometric mean worm counts, efficacy of the sarolaner + moxidectin + pyrantel combination was ≥ 95.2% against immature adult T. canis, ≥ 97.3% against adult T. canis, and ≥ 89.7% against adult T. leonina. There were no treatment-related adverse events in any study. CONCLUSIONS: These studies confirm the efficacy of a single dose of a new oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against immature adult and adult T. canis, and adult T. leonina infections in dogs.

Ascarid infection in wild Amur tigers (Panthera tigris altaica) in China.

BACKGROUND: Wild Amur tigers are a sparsely populated species, and the conservation of this species is of great concern worldwide, but as an important health risk factor, parasite infection in them is not fully understanding. RESULTS: In this study, sixty-two faecal samples were collected to investigate the frequency and infection intensity of Toxocara cati and Toxascaris leonina in wild Amur tigers. The T. cati and T. leonina eggs were preliminary identified by microscopy, and confirmed by molecular techniques. Infection intensity was determined by the modified McMaster technique. Phylogenetic trees demonstrated that T. cati of wild Amur tiger had a closer relationship with which of other wild felines than that of domestic cats. T. leonina of Amur tiger and other felines clustered into one clade, showing a closer relationship than canines. The average frequency of T. cati was 77.42% (48/62), and the frequency in 2016 (100%) were higher than those in 2013 (P = 0.051, < 0.1; 66.6%) and 2014 (P = 0.079, < 0.1; 72.2%). The infection intensity of T. cati ranged from 316.6 n/g to 1084.1 n/g. For T. leonina, only three samples presented eggs when the saturated sodium chloride floating method was performed, indicating that the frequency is 4.83% (3/62). Unfortunately, the egg number in faecal smears is lower than the detective limitation, so the infection intensity of T. leonina is missed. CONCLUSIONS: This study demonstrated that ascarids are broadly prevalent, and T. cati is a dominant parasite species in the wild Amur tiger population.

Prevalence of Toxocara and Toxascaris infection among human and animals in Iran with meta-analysis approach.

BACKGROUND: Toxocariasis is a worldwide zoonotic parasitic disease caused by species of Toxocara and Toxascaris, common in dogs and cats. Herein, a meta-analysis was contrived to assess the prevalence of Toxocara/Toxascaris in carnivore and human hosts in different regions of Iran from April 1969 to June 2019. METHODS: The available online articles of English (PubMed, Science Direct, Scopus, and Ovid) and Persian (SID, Iran Medex, Magiran, and Iran Doc) databases and also the articles that presented in held parasitology congresses of Iran were involved. RESULTS: The weighted prevalence of Toxocara/Toxascaris in dogs (Canis familiaris) and cats (Felis catus) was 24.2% (95% CI: 18.0-31.0%) and 32.6% (95% CI: 22.6-43.4%), respectively. Also, pooled prevalence in jackal (Canis aureus) and red fox (Vulpes vulpes) was 23.3% (95% CI: 7.7-43.2%) and 69.4% (95% CI: 60.3-77.8%), correspondingly. Weighted mean prevalence of human cases with overall 28 records was 9.3% (95% CI: 6.3-13.1%). The weighted prevalence of Toxocara canis, Toxocara cati, and Toxascaris leonina was represented as 13.8% (95% CI: 9.8-18.3%), 28.5% (95% CI: 20-37.7%) and 14.3% (95% CI: 8.1-22.0%), respectively. CONCLUSION: Our meta-analysis results illustrate a considerable prevalence rate of Toxocara/Toxascaris, particularly in cats and dogs of northern parts of Iran. The presence of suitable animal hosts, optimum climate and close contact of humans and animals would have been the reason for higher seroprevalence rates of human cases in our region. Given the significance clinical outcomes of human Toxocara/Toxascaris, necessary measures should be taken.

Gastrointestinal Parasite Infection in Cats in Daegu, Republic of Korea, and Efficacy of Treatment Using Topical Emodepside/Praziquantel Formulation.

The purpose of this study was 2-fold: 1) to investigate the prevalence of gastrointestinal parasite infection in cats reared in Daegu, Republic of Korea and 2) to assess the efficacy and safety of a topical emodepside/praziquantel formulation for cats with parasitic infections. The gastrointestinal parasite infections were examined microscopically using the flotation method. Of 407 cats, 162 (39.8%) were infected by at least one gastrointestinal parasite, including Toxocara cati (63.0%), Toxascaris leonina (31.5%), Taenia taeniaeformis (3.7%), and Cystoisospora felis (1.9%). None of the infected animals had multiple infections. When the data were analyzed according to sex, age, and type of cat, stray cats showed statistically higher prevalence than companion cats (P<0.05). On the 5th day after treatment, no parasitic eggs were detected using microscopic examination. In addition, no adverse effects, such as abnormal behaviors and clinical symptoms, were observed in the cats treated with the drug. These results quantify the prevalence of gastrointestinal parasites in cats in Daegu, Republic of Korea, and show that topical emodepside/praziquantel is a safe and effective choice for treating the parasitic infections in cats.

Ancient parasitic DNA reveals Toxascaris leonina presence in Final Pleistocene of South America.

Parasitological analysis of coprolites has allowed exploring ecological relationships in ancient times. Ancient DNA analysis contributes to the identification of coprolites and their parasites. Pleistocene mammalian carnivore coprolites were recovered from paleontological and archaeological site Peñas de las Trampas 1.1 in the southern Puna of Argentina. With the aim of exploring ancient ecological relationships, parasitological analysis was performed to one of them, dated to 16 573-17 002 calibrated years BP, with 95.4% probability. Parasite eggs attributed to Toxascaris sp. by morphological characters were isolated. DNA of coprolite and eggs was extracted to molecular identification. Ancient mitochondrial DNA analysis confirmed the zoological origin of the coprolite as Puma concolor and that of parasite eggs as Toxascaris leonina. This is the oldest molecular parasite record worldwide, and it supports the presence of this parasite since the Pleistocene in America. These findings have implications for the biogeographic history of parasites and for the natural history of the region.

Comparative analysis of mitochondrial DNA datasets indicates that Toxascaris leonina represents a species complex.

BACKGROUND: Toxascaris leonina is one of the most common intestinal parasites of canids and felids. In this study, we characterised the entire mitochondrial (mt) genome sequence of T. leonina from the cheetah and compared it with that of T. leonina from the dog. RESULTS: The entire mt genome sequence of T. leonina from the cheetah is 14,685 bp in size, which is 375 bp longer than that from the dog, and it is 408 bp longer than that from the South China tiger. The overall nucleotide sequence (except for the non-coding region) identity was 92.8% between the two mt genomes of T. leonina from the cheetah and the dog. For the 12 protein-coding genes, sequence difference between T. leonina from the cheetah and the dog was 5.0-9.7% at the nucleotide level and 1.0-7.2% at the amino acid level. Moreover, comparison of mt cox1 sequences among T. leonina isolates (n = 23) from different hosts revealed substantial nucleotide differences (10.6%). Phylogenetic analysis showed the separation of T. leonina from canid and felid hosts into three distinct clades. CONCLUSIONS: Taken together, these mtDNA datasets indicate that T. leonina from canid and felid hosts represents a species complex. Our results have implications for further studies of the molecular epidemiology, systematics and population genetics of this nematode.

Molecular data reveal cryptic speciation and host specificity in Toxascaris leonina (Nematoda: Ascarididae).

Toxascaris leonina (Ascarididae) is a cosmopolitan and polyxenical parasite whose host are canids and felids. To date, molecular phylogenetic studies included toxascarid representatives collected only from dogs or felids, therefore the intra-species differences between T. leonina collected from different host species has not been noticed. In this paper, we test the hypothesis of cryptic speciation in the T. leonina complex based on extended sequence data (ITS1, nad1, cox1) and individuals collected from dogs, felids and foxes. Phylogenetic analysis clustered T. leonina representatives into three well-supported clades depending on their host species, i.e. dogs and wolves, wild felids and foxes. Both genetic distances and the barcoding-gap analysis strongly support the species status of populations inhabiting different hosts. The results suggest additional genetic separation in felids. However, to determine the actual size of the Toxascaris complex, it would be necessary to analyse individuals collected from other canid and felid Toxascaris leonina host species.

Prevalence of Intestinal Helminth Infections in Dogs and Two Species of Wild Animals from Samarkand Region of Uzbekistan

This study aimed to determine the prevalence of intestinal helminth parasitic infections and associated risk factors for the human infection among the people of Samarkand, Uzbekistan. Infection status of helminths including Echinococcus granulosus was surveyed in domestic and wild animals from 4 sites in the Samarkand region, Uzbekistan during 2015–2018. Fecal samples of each animal were examined with the formalin-ether sedimentation technique and the recovery of intestinal helminths was performed with naked eyes and a stereomicroscope in total 1,761 animals (1,755 dogs, 1 golden jackal, and 5 Corsac foxes). Total 658 adult worms of E. granulosus were detected in 28 (1.6%) dogs and 1 (100%) golden jackal. More than 6 species of helminths, i.e., Taenia hydatigena, Dipylidium caninum, Diplopylidium nolleri, Mesocestoides lineatus, Toxocara canis, and Trichuris vulpis, were found from 18 (1.0%) dogs. Six (T. hydatigena, Toxascaris leonina, Alaria alata, Uncinaria stenocephala, D. caninum, and M. lineatus) and 2 (D. nolleri and M. lineatus) species of helminths were also detected from 5 Corsac foxes and 1 golden jackal, respectively. Taeniid eggs were found in 2 (20%) out of 10 soil samples. In the present study, it was confirmed that the prevalences of helminths including E. granulosus are not so high in domestic and wild animals. Nevertheless, the awareness on the zoonotic helminth infections should be continuously maintained in Uzbekistan for the prevention of human infection.

Gastrointestinal Parasite Infection in Cats in Daegu, Republic of Korea, and Efficacy of Treatment Using Topical Emodepside/Praziquantel Formulation

The purpose of this study was 2-fold: 1) to investigate the prevalence of gastrointestinal parasite infection in cats reared in Daegu, Republic of Korea and 2) to assess the efficacy and safety of a topical emodepside/praziquantel formulation for cats with parasitic infections. The gastrointestinal parasite infections were examined microscopically using the flotation method. Of 407 cats, 162 (39.8%) were infected by at least one gastrointestinal parasite, including Toxocara cati (63.0%), Toxascaris leonina (31.5%), Taenia taeniaeformis (3.7%), and Cystoisospora felis (1.9%). None of the infected animals had multiple infections. When the data were analyzed according to sex, age, and type of cat, stray cats showed statistically higher prevalence than companion cats (P<0.05). On the 5th day after treatment, no parasitic eggs were detected using microscopic examination. In addition, no adverse effects, such as abnormal behaviors and clinical symptoms, were observed in the cats treated with the drug. These results quantify the prevalence of gastrointestinal parasites in cats in Daegu, Republic of Korea, and show that topical emodepside/praziquantel is a safe and effective choice for treating the parasitic infections in cats.

In vitro study of disinfectants on the embryonation and survival of Toxascaris leonina eggs.

The effect of six available and commercial disinfectants on the embryonation and larval development of Toxascaris leonina eggs was studied. Dettol® and Virkon® both induced a 100% reduction in larval development (P ≤ 0.05). Dettol® resulted in deformed eggshells and a halt in embryonal development at 1 week post exposure. All Virkon®-treated eggs showed an early embryonic lysis 24 h post exposure. TH4+ and 70% ethanol both significantly (P ≤ 0.05) affected larval development, with 58.8 and 85.8% reduction, respectively. Neither sodium hypochlorite nor phenol significantly affected larval development (2.8 and 21.0%, respectively). Sodium hypochlorite treatment caused a visible decortication of the eggshell; however, phenol-treated embryonated Toxascaris eggs appeared more or less morphologically normal. In conclusion, the disinfectants tested induced variable degrees of decortication and suppression of larval development. Virkon®S was the most effective disinfectant against Toxascaris eggs, suggesting that it is the most advisable one to use. To the best of our knowledge, this is the first report of the use of Virkon®S as an ovicide and/or larvicide of helminths, particularly Toxascaris leonina.

A flotation/sieving method to detect Echinococcus multilocularis and Toxocara spp. eggs in soil by real-time PCR.

Soil can be a source of human infection by many zoonotic helminth species including Echinococcus multilocularis and Toxocara spp. The prevention of alveolar echinococcosis could be greatly improved through the identification of at-risk areas. Yet very few data are available about the detection of E. multilocularis in soil, while more studies have been reported for Toxocara spp. Identification of soil contamination by E. multilocularis eggs requires the use of specific methods. This study describes the development of a method for the detection of E. multilocularis in soil samples with the concentration of eggs using a flotation/sieving method and detection by duplex real-time polymerase chain reaction (PCR). Toxocara spp. egg detection was also undertaken due to the widespread presence of this parasite in soil, despite it being considered less pathogenic. Method sensitivity of 100% was reached for the detection of 10 E. multilocularis eggs spiked in 10 g of soil. Concerning Toxocara spp., method sensitivity was lower but assumed to be due to the reduced effectiveness of the DNA extraction protocol. The parasitological status for E. multilocularis and Toxocara spp. of 63 carnivore fecal samples collected in highly endemic rural areas of France and of soil samples collected under and near these fecal samples was compared. The contamination of soil samples collected under positive fecal samples for E. multilocularis (n = 3) or Toxocara spp. (n = 19) confirmed the transfer of eggs from the definitive host to the environment.