Epidemiological survey on cystic echinococcosis in wild boar from Central Italy.

Despite the wide distribution of wild boar populations in Italy and the increase of its diffusion in urbanized areas, only one case report has described the occurrence of Echinococcus granulosus s.l. in a wild boar from Marche (Central Italy). The present study investigated the presence of E. granulosus sensu lato with an epidemiological survey on wild boars from central Italy that had been killed during hunting season. Seven hundred sixty-five (765) adult wild boars were examined during the 2016-2017 hunting season. Of these animals, 1.0% (8/765) were positive to E. granulosus s.l. with a fertility of 0.3% (2/765), and 2.9% animals (22/765) were positive for the metacestode stage of Taenia hydatigena (Cysticercus tenuicollis), while 0.5% (4/765) showed mixed infection (E. granulosus s.l. + T. hydatigena). Sixteen hydatids were found, of which 12.5% were fertile, 37.5% were sterile, 31.3% were caseous, and 18.8% were calcified. Eight hydatids (two fertile and six sterile cysts) were molecularly characterized by analysis of the mitochondrial gene, cytochrome c oxidase subunit 1 (cox1), and the NADH dehydrogenase subunit 1 (ND1). Hydatids found in wild boars were characterized as E. granulosus sensu stricto (G1 genotype). The present survey represents the first epidemiological study on cystic echinococcosis in wild boar in Italy which highlights the need for more extensive epidemiological investigations to determine the causal factors, economic impact, and public health importance of the disease in this livestock-wildlife setting.

Mitochondrial haplotypes of Aelurostrongylus abstrusus and Troglostrongylus brevior (Nematoda, Metastrongyloidea) from domestic and wild felids.

The lungworm Aelurostrongylus abstrusus is the most important respiratory parasite of domestic cats. Pulmonary aelurostrongylosis has been reported in wild felids, though unequivocally evidence of wildlife infection by A. abstrusus is scant. Recently, Troglostrongylus brevior, a lungworm usually infecting wild felids, has been described in domestic cats from Mediterranean areas. The present work evaluates the sequence variation of an informative region within the gene encoding the mitochondrial cytochrome c oxidase subunit 1 of A. abstrusus and T. brevior, in order to provide novel information on the genetic make-up of these lungworms. Parasitic stages of A. abstrusus and T. brevior were collected from domestic and wild hosts (i.e., domestic cat, European wildcat, caracal, serval, and lion) from Italy, Greece, and South Africa. Five (HI-HV) and four (HI-HIV) haplotypes were recorded for A. abstrusus and T. brevior, respectively, mostly shared between domestic and wild felids in different geographical areas. The phylogenetic analysis showed that all haplotypes of A. abstrusus and T. brevior clustered as monophyletic groups with a strong nodal support, indicating that all haplotypes identified were distinct from each other. All sequence types represent two distinct species, A. abstrusus and T. brevior, and these genetic convergences are also detected within and among populations of these nematodes, irrespective of their hosts and geographical origin. The occurrence of A. abstrusus and T. brevior haplotypes in different hosts from the same regions and between different countries indicates that the same lungworm populations circulate in domestic and wild hosts under the same routes of transmission.

Neospora caninum seropositivity and reproductive risk factors in dogs.

Despite the importance of Neospora caninum in veterinary medicine, knowledge of distribution of neosporosis in dog populations in some countries is still poor. The aims of the present study were to determine the occurrence of anti-N. caninum antibodies in one-hundred dogs living in cattle farms or dog breedings in central Italy and to evaluate the risk factors associated with seropositivity. The incidence of reproductive system disorders (e.g. infertility after first pregnancy) was also evaluated. Serum from breeding and farm dogs was tested to an indirect immunofluorescent antibody test (IFAT) to assess the occurrence of seropositivity. Management and individual data were collected and analysed both by linear and logistic multiple-regression models to find reliable predictors of seroprevalence and anti-N. caninum antibody level. The seropositivity for N. caninum was 32%. Dogs reared for breeding and presence of cattle on the farm were associated with seropositivity for N. caninum. Dogs living in the cattle farms showed a higher seropositivity for N. caninum (46%) compared with those living in dogs breeding (18%) (P < 0.05). The high presence of seropositive dogs in cattle farms of the study region demonstrates the potential risk of horizontal transmission of N. caninum between dogs and cattle, regardless the occurrence of reproductive system disorders or with infectious bovine tissues contact. Although the Neospora seropositivity in dog breedings may appear relatively low if compared with that found in dogs living with livestock, this infection, apparently underestimated, should be considered as a potential serious problem in canine medicine.

Aelurostrongylus abstrusus in wild felids of South Africa.

The increasing interest on respiratory nematodes of domestic cats (Felis silvestris catus) has recently stimulated several studies on their epidemiology and geographic distribution. At the same time, there are still important gaps in our knowledge of the infections caused by respiratory nematodes in wild felids. The present study investigated the occurrence of pulmonary parasites in wild hosts housed in sanctuaries and protected areas of South Africa. Faecal samples collected from seven species of wild felids living in three study sites were copromicroscopically and genetically examined. Of twenty-one samples six, i.e. three from caracals (Caracal caracal), two from lions (Panthera leo) and one from a serval (Leptailurus serval), scored positive for the metastrongyloid Aelurostrongylus abstrusus at copromicroscopic and/or molecular tests. No other lungworms were recorded. The occurrence of the cosmopolitan cat lungworm A. abstrusus in wild hosts has been so far questioned. Importantly, the present findings represent an unequivocal evidence of the capability of A. abstrusus to infect some species of wild felids. Further studies are warranted to understand the epidemiological patterns of lungworms in wild and domestic felids, and to better investigate the impact of these parasitoses on health and welfare of wild animals.

Novel Molecular Assay for Simultaneous Identification of Neglected Lungworms and Heartworms Affecting Cats.

Feline lungworms and heartworms are stimulating the interest of the scientific community due to their clinical impact and apparent geographical expansion. Diagnosis of the infections caused by these nematodes is indeed challenging. This report describes a novel multiplex PCR able to identify simultaneously three species of lungworms (Aelurostrongylus abstrusus and Troglostrongylus brevior) and heartworms (Angiostrongylus chabaudi) affecting felids. Epidemiological and clinical perspectives are discussed.

Larval development of Angiostrongylus vasorum in the land snail Helix aspersa.

The metastrongyloid nematode Angiostrongylus vasorum affects the heart and pulmonary arteries of dogs and wild animals. Over the recent years, dog angiostrongylosis has gained great attention in the veterinary community for the expansion of its geographic range and for a rise in the number of clinical cases. Global warming, changes in phenology of mollusc intermediate hosts and movements of wild reservoirs have been evocated in the spreading of mollusc-borne parasites, including A. vasorum. The land snail Helix aspersa, a vector of other respiratory metastrongyloids, is endemic in most regions of the World, where it is a pest outside its native Mediterranean range. In the present study, the susceptibility and suitability of H. aspersa as an intermediate host of A. vasorum were investigated along with the characteristics of larval recovery and development following two different ways of inoculation, i.e. experimental (group A) vs natural infection (group B). After infections, the snails were kept at environmental conditions for 2 months. Five snails from groups A and B were randomly selected, digested and examined at 15-day intervals for 2 months. L1s, L2s and L3s were microscopically identified based on key morphological and morphometric characteristics and their identity was genetically confirmed. The results showed that A. vasorum may reach the infective stage in H. aspersa and that uptake of larvae and parasitic burden within the snails depend on the grazing capability of the molluscs. Biological and epidemiological implications are discussed.

Zoonotic parasites in feces and fur of stray and private dogs from Italy.

The present study evaluated the occurrence of zoonotic parasites in feces and on fur of stray and private dogs living in Italy. Individual fecal samples collected from 117 and 385 kenneled (i.e., rescue shelter) and privately owned dogs, respectively, were examined by conventional copromicroscopy. Samples positive for Giardia duodenalis and Cryptosporidium spp. were subjected to further genetic characterization. Additionally, 174 fur samples of private and kenneled dogs living in the same area, 27 of which were also subjected to copromicroscopical examinations, were examined for the presence and viability of parasite elements. Out of 502 fecal samples, forty-one (8.2%) scored positive for G. duodenalis cysts while one (0.2%) for Cryptosporidium oocysts. Nine private dogs were molecularly positive for G. duodenalis assemblage C (n. 7), assemblage D (n. 1), and assemblages C + D (n. 1), while 11 kenneled dogs were positive for assemblage C (n. 8), assemblage D (n. 1), and assemblages C + D (n. 2). Cryptosporidium spp. were identified as C. canis in a private dog. One hundred and seventy-two dogs (34.3%), i.e., 92 private and 80 kenneled, were positive for zoonotic nematodes: Toxocara canis (6.6 %), Ancylostoma caninum (6.8%), and Capillaria aerophila (0.6%). Unviable eggs of Toxocara spp. were found on the hair of five (2.9%) private dogs. The present findings indicate that canine feces from both private and kenneled animals may contain zoonotic parasites and may be a potential risk for humans and other animals, especially when they contaminate the environment. The role of dog fur as source of human infections should be further investigated.

Mixed infection by Aelurostrongylus abstrusus and Troglostrongylus brevior in kittens from the same litter in Italy.

Parasitic nematodes affecting the respiratory system of felids are spreading in endemic regions and emerging in previously free areas and/or hosts. This is particularly the case of the cat lungworm Aelurostrongylus abstrusus, which can cause respiratory signs in cats all over the world. Additionally, Troglostrongylus brevior has been recently found in domestic cats from Ibiza Island in Spain and Southern Italy. The present paper describes the first mixed infection by these lungworms in kittens belonging to the same litter. Two ∼10-11 weeks old kittens were found infected by A. abstrusus and T. brevior at a copromicroscopical examination. The identity of larvae shed by faeces were confirmed with an already validated PCR specific for A. abstrusus and a novel DNA-based assay specific for T. brevior. One kitten showed severe respiratory signs and died despite an anthelmintic treatment, while the other had a subclinical infection and recovered after a parasiticide administration with milbemycin oxime. New insights into epidemiology, biology, clinical aspects and control of these parasitoses are discussed.

Zoonotic intestinal helminthes diagnosed in a 6-year period (2015-2020) in privately owned dogs of sub-urban and urban areas of Italy.

Intestinal helminthes of dogs have a relevant role for health and welfare of canine populations and many of them are zoonotic. Thus, a constant surveillance is pivotal to safeguard companion dogs and human health. Data from faecal examinations of pet dogs obtained in the last six years during the routine activity of the laboratory of Parasitology and Parasitic diseases of the University Teaching Veterinary Hospital of the University of Teramo, Italy, are here reported. From 2015 to 2020 a total of 1083 individual faecal samples from privately owned dogs were examined using conventional copro-microscopic techniques. Endoparasite elements were found in 278 (25.7%) dogs, and among them, eggs of intestinal zoonotic helminthes were detected in 184 (17%) samples. The most common zoonotic parasites were Toxocara canis and hookworms (8.9% positivity rate for both). Most dogs (88%) were positive for a single zoonotic parasite while 12% of the positive animals harbored two or more zoonotic helminthes. A statistical analysis showed a significant association between dogs with less than one year of age and positivity to at least one intestinal zoonotic helminth, and that infections by T. canis are significantly more prevalent in dogs under one year of age. Despite being well known in canine clinical practice, these results indicate that zoonotic helminthes are still frequent in owned dogs. Thus, increased awareness of veterinary practitioners and pet owners is necessary to implement current diagnostic and control strategies to minimize the risk of zoonotic transmission of intestinal helminthes.

A Comparison of Copromicroscopic and Molecular Methods for the Diagnosis of Cat Aelurostrongylosis.

The gold standard method for the diagnosis of cat aelurostrongylosis is the detection of Aelurostrongylus abstrusus first stage larvae with the Baermann's examination. Nevertheless, molecular assays have shown higher diagnostic performances compared to copromicroscopy. This study evaluated the usefulness of an A. abstrusus species-specific PCR on different biological samples collected in clinical settings from 100 privately-owned cats in Italy (n. 60) and Greece (n. 40). A fecal sample was collected from each animal and a pharyngeal swab was also obtained for cats from Italy. All stool samples were subjected to flotation and Baermann's test. The cats were categorized in three groups based on the results of copromicroscopy, i.e., Group A (n. 50 cats with A. abstrusus infection regardless of positivity for other helminths), Group B (n. 25 cats negative for A. abstrusus but positive for at least one of any other helminth), Group C (n. 25 cats negative for any helminth). DNA was extracted from individual aliquots of feces, flotation supernatant, Baermann's sediment and the pharyngeal swab and then subjected to a PCR specific for A. abstrusus. At least one fecal aliquot or the pharyngeal swab scored positive by the A. abstrusus-specific PCR for 48/50 (96%) cats enrolled in Group A; in particular, 38/50 (76%), 35/50 (70%), 41/50 (82%) and 21/25 (84%) DNA extracts from feces, flotation supernatant, Baermann's sediment and pharyngeal swabs were positive by PCR. These results confirm that molecular tools are highly sensitive and specific and indicate that pharyngeal swabs are the most suitable sample for molecular analysis in clinical settings.

Species-specific identification of equine cyathostomes resistant to fenbendazole and susceptible to oxibendazole and moxidectin by macroarray probing.

Cyathostome populations in horses on two farms located in central Italy with a history of fenbendazole (FBZ) resistance were investigated with the Faecal Egg Count Reduction Test to evaluate the susceptibility to oxibendazole and moxidectin. Faecal eggs were collected pre- and post-treatment on each farm and molecularly examined with a Reverse Line Blot (RLB) assay able to unequivocally detect and identify 13 cyathostome species. Resistance to FBZ was confirmed on both farms, while oxibendazole and moxidectin demonstrated 97% and 100% efficacy, respectively. Overall eight species of cyathostomes (Coronocyclus labiatus, Cylicocyclus ashworthi, Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicostephanus calicatus and Cylicocyclus insigne) were identified in pre-treatment samples. Coronocyclus labiatus and C. goldi were identified after treatment with FBZ while C. calicatus and C. labiatus were shown to be <100% susceptible to oxibendazole. These data confirm that resistance to benzimidazoles is established in cyathostome populations from horse farms in Italy and that they are susceptible to moxidectin. The oxibendazole has been successfully demonstrated for the first time as effective against Italian populations of cyathostomes resistant to other benzimidazoles. The RLB assay herein used showed to be useful to study the distribution of these parasitic populations at species level under field conditions and could represent a powerful tool in broader investigation of drug resistance in horse farms from several countries.

Immunoenzymatic analysis and genetic detection of Cryptosporidium parvum in lambs from Italy.

Cryptosporidiosis is a worldwide-diffused protozoan disease causing important economic losses to animal husbandry and livestock production. Additionally, several species/genotypes of Cryptosporidium have a relevant zoonotic potential and ruminants may be important sources of infection for human beings. Nonetheless, in Europe, little is known of the presence of Cryptosporidium in sheep nor on the species/genotypes involved. To obtain information on the occurrence of cryptosporidiosis in lambs and the potential zoonotic role of the Cryptosporidium isolates, one hundred and forty-nine faecal samples individually collected from lambs in central Italy have been examined for the presence of Cryptosporidium. All faecal specimens were processed with a commercial ELISA kit immunoassay and all ELISA-positive samples were further analyzed genetically. Twenty-six ELISA-positive samples scored positive at the PCR and the sequences obtained displayed 100% identity with the zoonotic Cryptosporidum parvum. This work suggests for the first time that lambs in Italy may shed C. parvum, thus representing a potential public health hazard.

Application of a Reverse Line Blot hybridisation assay for the species-specific identification of cyathostomins (Nematoda, Strongylida) from benzimidazole-treated horses in the Slovak Republic.

Five horse farms located in eastern Slovakia were investigated for the presence of benzimidazole-resistant strongyles by faecal egg count reduction test and egg hatch assay. Coprocultures were prepared for each farm from faecal samples taken pre- and post-treatment and harvested larvae were molecularly examined with a Reverse Line Blot assay. Faecal egg count reduction values ranged from 0 to 52.5% and all farms were positive for benzimidazole-resistant cyathostomins. Seven benzimidazole-resistant cyathostomin species were molecularly identified on farms before and also after treatment. These data demonstrate that resistance to benzimidazoles is well established in cyathostomin populations from horse farms in the Slovak Republic and that the molecular assay was able to determine the species-specific distribution of resistant cyathostomins under field conditions.

Phylogenetic relationships of Habronema microstoma and Habronema muscae (Spirurida: Habronematidae) within the order Spirurida inferred using mitochondrial cytochrome c oxidase subunit 1 (cox1) gene analysis.

The present study investigated genetic variability within a population of Habronema microstoma and Habronema muscae (Spirurida: Habronematidae) affecting horses in an endemic area of central Italy using polymerase chain reaction (PCR)-coupled sequencing of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). No different cox1 sequences were detected in any of the H. muscae individual, while two haplotypes representing H. microstoma individuals differed for one substitution. The pairwise distance between the H. muscae and H. microstoma was 11%, coding for five amino acid changes. The sequence of an informative region within the cox1 gene of H. microstoma and H. muscae was analyzed by Maximum Likelihood and Bayesian phylogenetic methods using available mitochondrial sequences spirurid taxa belonging to Filarioidea, Thelazioidea, and Habronematoidea. Phylogenetic analysis supported the split of the tree into two sister spirurid groups, Habronematoidea and Filarioidea + Thelazioidea. The phylogenetic and evolutionary implications of Habronema with Filaroidea and Thelazioidea are discussed.

Efficacy and safety of imidacloprid 10%/moxidectin 1% spot-on formulation in the treatment of feline aelurostrongylosis.

The objective of the present study was to evaluate the efficacy and safety of the antiparasitic spot-on formulation containing imidacloprid 10%/moxidectin 1% (Advocate, Bayer) in the treatment of natural feline infection with the lungworm Aelurostrongylus abstrusus (Nematoda, Strongylida). The efficacy of Advocate administered once was tested in comparison to a control oral formulation containing fenbendazole 18.75% (Panacur Intervet) administered over three consecutive days based on larvae per gramme of faeces (LPG), measured on days 28 +/- 2 following treatment and compared to counts on days -6 to -2. In total 24 cats treated either with Advocate (n = 12) or with Panacur (n = 12) were included. Mean LPG postbaseline (days 28 +/- 2) were low in both treatment groups, i.e., 0 LPG for Advocate and 1.3 LPG for Panacur. Reduction of post-baseline larval counts showed Advocate (100% reduction) to be superior in efficacy compared to the control product (99.29% reduction). No treated animals showed adverse events. This trial demonstrated that both Advocate spot-on formulation and Panacur oral paste are safe and effective in the treatment of aelurostrongylosis in cats. Future practical perspectives in feline medicine and the major advantages of the spot-on product compared to the oral paste are discussed.

Efficacy and safety of emodepside 2.1%/praziquantel 8.6% spot-on formulation in the treatment of feline aelurostrongylosis.

The objective of the present study was to evaluate the efficacy and safety of the antiparasitic spot-on formulation containing emodepside 2.1%/praziquantel 8.6% (Profender, Bayer) in the treatment of natural feline infection with the lungworm Aelurostrongylus abstrusus (Nematoda, Strongylida). Efficacy of Profender given once at the licensed dose was tested in comparison to a control oral formulation containing fenbendazole 18.75% (Panacur, Intervet) given over three consecutive days at the licensed dose. Efficacy assessment was based on larvae per gramme of faeces (LPG) counts, measured on days 28 +/- 2 following treatment and compared to counts on days -6 to -2. In total 24 cats treated either with Profender (n = 12) or with Panacur (n = 12) were included in the assessment of efficacy and safety. Mean LPG post-baseline counts (days 28 +/- 2) were 1.3 LPG for both Profender and Panacur, demonstrating similar efficacy of 99.38% for Profender and 99.29% for the control product. No treated animals showed adverse events. This trial demonstrated that both Profender spot-on formulation and oral paste Panacur are safe and effective in the treatment of aelurotrongylosis in cats. Future practical perspectives in feline medicine and the major advantages of the spot-on product compared to the oral paste are discussed.

Pilot study evaluating the efficacy of a topical formulation containing emodepside and praziquantel in the treatment of natural feline troglostrongylosis.

BACKGROUND: Troglostrongylus brevior, a lungworm usually affecting wild felids, has been recently recorded in a number of cases in domestic cats, mainly in Mediterranean areas. Although feline troglostrongylosis is a severe and life-threatening disease, especially in young cats, treatment options are very limited. The present study evaluated the efficacy and safety of a spot-on formulation containing emodepside 2.1% and praziquantel 8.6% (Profender®, Bayer), which is licensed for treatment of the more common cat lungworm Aelurostrongylus abstrusus, for the treatment of natural troglostrongylosis. METHODS: Sixteen cats enrolled in the study were 1:1 allocated to two groups, i.e. Group T, treated with Profender® spot-on on days 0 and 14 (± 2) at the recommended clinical dose, and Group C which remained untreated. After study completion, the control cats received two rescue treatments with Profender® on days 28 (± 2) and 42 (± 2). The primary efficacy criterion was the absence of T. brevior L1 following treatment. Other efficacy parameters were the quantitative comparison of L1 presence before (baseline) and after treatment in both groups, and the comparison of clinical signs pre- and post-treatment. RESULTS: In terms of stopping larval shedding, Profender® showed an efficacy of 97% and 97.5% (arithmetic and geometric means, respectively) for group T, 97.1% and 98.5% for group C after one administration, and 100% for both groups after two doses. Overall, 12 cats showed clinical signs related to T. brevior. Specifically, 9 were clinically affected before treatment while clinical signs appeared after the first treatment in 3 cats. At the end of the study, all symptomatic cats fully recovered with the exception of 3 cats that showed clinical signs similar to those observed at the pre-treatment examination at the end of the study. CONCLUSIONS: This study shows that Profender® is effective against T. brevior.

Diagnostic and clinical implications of a nested PCR specific for ribosomal DNA of the feline lungworm Aelurostrongylus abstrusus (Nematoda, Strongylida).

Aelurostrongylus abstrusus (Nematoda, Strongylida, Metastrongyloidea) is a cosmopolitan parasite of cats and causes severe respiratory distress. Information on the biology and epidemiology of feline aelurostrongylosis is fragmentary, mainly due to the limits inherent in the classical diagnosis. In the present work, a two-step nested PCR based on the use of genetic markers in the second internal transcribed spacer (ITS2) of ribosomal DNA was established for A. abstrusus in different biological samples. Characterization of the ITS2 (321 bp of length) revealed a G+C content of 39.5%. To exploit the sequence difference between the ITS2 of A. abstrusus and those of other common feline endoparasites, specific primers were designed and tested by PCR for their specificities and sensitivities. The PCR assay was validated on a panel of fecal (i.e., feces, flotation supernatant, and Baermann sediment) and pharyngeal swab samples from cats with known histories of lungworm infections, and it showed a specificity of 100% and a sensitivity of up to 96.6%. Also, the nested PCR was able to identify cats that were actually infected but that tested negative by the classical diagnostic methods. This PCR method was shown to be a powerful tool for the molecular diagnosis of feline aelurostrongylosis, overcoming the constraints of the classical diagnosis. The implications of such a molecular tool for further bioepidemiological studies of both intermediate and definitive hosts have been discussed.

Diagnosis and risk factors of Aelurostrongylus abstrusus (Nematoda, Strongylida) infection in cats from Italy.

Aelurostrongylus abstrusus (Nematoda, Strongylida) in cats and associated risk factors have been investigated by classical coprology in central (site A) and southern (site B) Italy, i.e. by floatations with sugar and zinc sulphate solutions and a Baermann technique. Overall, 227 individual stool samples (i.e. 162 from site A and 65 from site B) were processed and risk factors were related to infection by binary logistic multiple-regression models. The presence of A. abstrusus was used as the dependent variable and the epidemiological data as independent variables. Twenty-eight (17.3%) and 12 (18.5%) cats were positive for A. abstrusus in sites A and B, respectively, both using the Baermann and flotation with zinc sulphate solution methods. Six and three (from site A and B, respectively) of the infected cats were negative for A. abstrusus when faeces were processed with sugar solution. Stray and free-ranging (P=0.357), young cats (P=0.008) and the presence of respiratory symptoms (P=0.000) were risk factors for A. abstrusus infection. The results suggest that A. abstrusus is spread in Italy. Furthermore, these results possibly include infection in the differential diagnosis of feline respiratory diseases and offer a correct diagnostic approach by using either a Baermann method or flotation with zinc sulphate solution in suspected cases.

Haplotypic variability within the mitochondrial gene encoding for the cytochrome c oxidase 1 (cox1) of Cylicocyclus nassatus (Nematoda, Strongylida): evidence for an affiliation between parasitic populations and domestic and wild equid hosts.

This study investigated the genetic variability within Cylicocyclus nassatus (Nematoda, Strongylida, Cyathostominae) collected from different domestic and wild hosts (i.e. horse, donkey, Przewalskii horse, tarpan and Turkmen kulan) and localities in Europe and/or USA. The ribosomal Internal Transcribed Spacer 2 (ITS2) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were PCR-amplified and sequences characterized from seventy individual parasitic specimens. While ITS2 displayed 0-0.6% variation rate among all individual adult specimens of C. nassatus examined, 22 different sequence variants (haplotypes) of cox1 were detected. Nucleotide variation was detected at 75 of the total 689 positions (overall 10.8% rate of intraspecific nucletidic difference) in the cox1, with the absence of invariable positions among specimens collected from each equid species or country. Conversely, two haplotypes were detected in horses from USA and in donkeys of Italy and Ukraine, respectively. The absence of haplotypes shared by the equid species suggests an affiliation of C. nassatus populations to their specific host. The results of the present study demonstrated that the characterization of mitochondrial regions may have important implications for studying the genetic structure and biology of equine cyathostomes, and to exploit taxonomic issues and practical implications related to the spread of anthelmintic resistance.