Topic:Cyathostomins
Cyathostomins, commonly referred to as small strongyles, are parasitic nematodes that inhabit the gastrointestinal tract of horses. They are among the most prevalent internal parasites affecting equine populations globally. These parasites undergo a direct life cycle, with larvae developing in the environment and being ingested by horses, where they mature into adult worms within the large intestine. Cyathostomins are known for their ability to encyst in the intestinal wall, which can complicate treatment and management strategies. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, epidemiology, and control measures of cyathostomins in horses, as well as their impact on equine health and well-being.
Ability of the fungus Duddingtonia flagrans to adapt to the cyathostomin egg-output by spreading chlamydospores. The analysis of the capability of the nematode trapping-fungus Duddingtonia flagrans to adapt to the cyathostomin egg-output in horses was evaluated. Fecal samples from 196 pasturing autochthonous Pura Raza Galega horses were collected from the rectum and then divided according to the egg-output into three groups: ≤ 300, 310-800 and >800 eggs per gram feces. Four doses of chlamydospores (0.1, 0.2, 0.4 and 0.8 × 10(6)/100g feces) were directly spread onto fecal pats on the ground, remaining one without treatment as control. Fecal pats confirmed the presence of gastrointestinal nematode la...
Three recently recognized species of cyathostomes (Nematoda: Strongylidae) in equids in Kentucky. Three species of cyathostomes--Cylicocyclus ashworthi, Cylicostephanus bidentatus, and Cylicostephanus hybridus were identified recently in horses in Kentucky. General characteristics and distinguishing description of these species are presented. Distribution of these species and their role in the horse strongylid community are discussed. The importance of examining the entire contents of the large intestine or alternatively a high number of specimens in order to recover and identify species residing in low numbers is stressed.
Biological control of cyathostomin (Nematoda: Cyathostominae) with nematophagous fungus Monacrosporium thaumasium in tropical southeastern Brazil. Horses are hosts to a wide variety of helminthes; the most important are the cyathostomin, or small strongyles. The viability of a fungal formulation (pellets) using the nematode-trapping fungus Monacrosporium thaumasium was assessed in biological control of horse cyathostomin. Two groups (fungus-treated and control) consisted of six mares in each group, crossbred (ages of 2.5 and 3.5 years), were placed in pastures of Cynodon sp. naturally infected with horse cyathostomin larvae. In the treated group, each animal received 1g/10 kg body weight (0.2g/10 kg live weight of fungus) of pellets of s...
Large intestinal mast cell count and proteinase expression is associated with larval burden in cyathostomin-infected horses. Cyathostomins are the principal pathogenic nematode of equidae worldwide. In other species mast cell (MC) proteinases, in particular chymases, appear to have protective roles. Knowledge of the equine intestinal immune response to cyathostomins is limited. Objective: To investigate MC numbers and proteinase expression in equine cyathostomin-infected large intestine. Objective: MC populations in the large intestine are positively associated with cyathostomin burden and predominantly express chymase. Methods: The caecal cyathostomin burden of naturally infected horses (n = 25) was determined by l...
In vitro selection and differentiation of ivermectin resistant cyathostomin larvae. Cyathostomins are considered to be the primary helminth pathogen of horses and macrocyclic lactones (ML) are the most frequently used anthelmintics. Therefore, ML resistance is a serious threat for the control of these parasites. In the present study ivermectin resistant cyathostomin L3 were in vitro selected, using a reiterative larval migration inhibition assay (rLMIA) and differentiated by reverse line blot (RLB). Larvae were obtained from two populations, one from a never treated, free-roaming horse population in the nature reserve Oostvaardersplassen (OVP) and the other from regularly ive...
Morphology and diagnosis of the fourth-stage larva of Coronocyclus labratus (Looss, 1900) (Nematoda: Strongyloidea) parasitising equids. The fourth larval stage (L4) of Coronocyclus labratus (Looss, 1900) Hartwich, 1986, one of the common species of the Cyathostominae found in equids, is identified and described. The larvae found were identified as C. labratus by finding moulting forms possessing characters of both larval and adult stages. The larvae are similar to those of Cylicocyclus leptostomum (Kotlán, 1920) Foster, 1936, Cyathostomum catinatum Looss, 1900 and Cylicostephanus goldi (Boulenger, 1917) Lichtenfels, 1975. The buccal capsule (BC) wall of the L4 of Cylicocyclus leptostomum is thinner than that of Coronocyclus l...
Determination of ivermectin efficacy against cyathostomins and Parascaris equorum on horse farms using selective therapy. Ivermectin resistance has recently been described in Parascaris equorum and there have been reports from several countries of a shortened egg reappearance period (ERP) following ivermectin treatment for cyathostomins. This study was aimed at determining the efficacy of ivermectin in treating cyathostomins and P. equorum in Danish horses. A total of 196 animals were selected from 52 farms, all of which were using a selective anthelmintic treatment strategy. ERP was investigated with weekly samples from 96 horses from nine farms. Horses were treated with ivermectin oral paste by their owners at ...
Parascaris and cyathostome nematodes in foals: parasite in transit or real infection? Faecal egg counts were performed in 187 foals of a large Polish stud farm between February and September 2007. Eggs of Parascaris equorum were present in faeces of 7% and those of cyathostomins in 13% of the foals aged less than 194 days. Information dealing with age of foals and/or efficiency of ivermectin treatment as well as the nematode parasite prepatent periods, it can be conducted that most of the infections recorded on the basis of faecal egg counts were false-infections in animals up to the age of six months, probably due to the ingestion of infected faeces of their dam or some other ...
Treatment of horses with cypermethrin against the biting flies Culicoides nubeculosus, Aedes aegypti and Culex quinquefasciatus. An in vitro assay was used to assess the efficacy of the proprietary pyrethroid insecticide cypermethrin applied to horses (Deosect spray, 5.0%, w/v Fort Dodge Animal Health) against the biting midge Culicoides nubeculosus (Meigen) (Diptera: Ceratopogonidae) and the mosquitoes Aedes aegypti Linneaus and Culex quinquefasciatus Say (Diptera: Culicidae). Hair was collected from the back, belly and legs of the horses immediately prior to treatment and 7, 14, 21, 28 and 35 days after treatment, and also from untreated controls. In laboratory assays groups of 10 adult female C. nubeculosus, Ae. aegy...
Distribution and species-specific occurrence of cyathostomins (Nematoda, Strongylida) in naturally infected horses from Italy, United Kingdom and Germany. A broad scale study was carried out in 2008 to evaluate the distribution and species-specific occurrence of cyathostomin populations in horse yards from Europe. In total 102 properties and 3123 horses were included in Italy (60 yards and 1646 animals), United Kingdom (22 yards and 737 animals) and Germany (20 yards and 740 animals). Individual faecal samples were examined with a McMaster technique while pooled samples were subjected to the microscopic examination of in vitro cultured larvae and to a Reverse Line Blot (RLB) assay able to molecularly identify the most diffused 13 species of cyat...
Faecal Cyathostomin Egg Count distribution and efficacy of anthelmintics against cyathostomins in Italy: a matter of geography? In the framework of a trial carried out in 2008 in Europe to evaluate the efficacy of major parasiticides against horse cyathostomins, pre- and/or post-treatment Faecal Egg Counts (FEC) were evaluated in a total of 84 yards and 2105 horses from nine different regions from the South, the Center, the North-Center and North-East of Italy. Specifically, on the basis of FECs of the horses present in each property, 60 out of the 84 yards were enrolled for a Faecal Egg Count Reduction Test (FECRT) using fenbendazole, pyrantel, ivermectin and moxidectin. Results: Of the 1646 horses bred in the 60 recr...
Equine cyathostomins: a review of biology, clinical significance and therapy. The small strongyles of horses, also known as cyathostomins, are considered the most prevalent and pathogenic parasites of horses today. The clinical syndrome of larval cyathostominosis which occurs as a result of mass emergence of inhibited stages has a high fatality rate despite the best standard of care given to affected horses. Management of the challenge level of cyathostomins to prevent the syndrome is preferable. Many different management programmes have been tried over the past two decades, with mixed success. Programmes have relied heavily on repeated use of anthelmintic treatments th...
Determination of genomic DNA sequences for beta-tubulin isotype 1 from multiple species of cyathostomin and detection of resistance alleles in third-stage larvae from horses with naturally acquired infections. Genetic resistance against benzimidazole (BZ) anthelmintics is widespread in cyathostomins, the commonest group of intestinal parasitic nematodes of horses. Studies of BZ-resistant nematodes of sheep, particularly Haemonchus contortus, have indicated that an anthelmintic resistance-conferring T/A polymorphism, encoding an F (phenylalanine) to Y (tyrosine) substitution, in beta-tubulin isotype 1 is present at two loci, codons 167 and 200 (F167Y, F200Y). Recent studies using complementary (c) DNA derived from BZ-susceptible and -resistant cyathostomins identified statistical differences in the f...
Anthelmintic resistance in cyathostomin populations from horse yards in Italy, United Kingdom and Germany. A large survey was carried out in 2008 in Europe to evaluate the efficacy of fenbendazole (FBZ), pyrantel (PYR), ivermectin (IVM) and moxidectin (MOX), i.e. the major anthelmintic molecules used in current practice against cyathostomins affecting horses. A total of 102 yards and 1704 horses was studied in three countries: 60 yards and 988 horses from Italy, 22 and 396 from the UK, 20 and 320 from Germany. The survey consisted of Faecal Egg Count Reduction Tests (FECRTs) with a faecal egg count reduction (FECR) categorization of (I) resistance present if FECR <90% and the lower 95% confidenc...
Identification and characterisation of an immunodiagnostic marker for cyathostomin developing stage larvae. Parasitic nematodes of the group Cyathostominae are an important cause of disease in horses. This group consists of approximately 50 species, all of which have similar life cycles that involve encystment of larval stages in the large intestinal wall. Encysted larvae can persist for months to years and, occasionally, large numbers can accumulate and emerge synchronously to cause severe pathology, resulting in diarrhoea, weight loss, colic and/or oedema. This syndrome, known as larval cyathostominosis, can be fatal in up to 50% of cases, despite treatment. There is no diagnostic method that enab...
Mechanical recovery of inhibited cyathostomin larvae from equine intestinal tissue. The Stomacher is very widely used in food and medical research for extracting tissues. To determine whether nematode larvae were disrupted by the Stomacher, L3 larvae of Haemonchus contortus were homogenised for up to 40 min at full power but no larval disruption occurred. Therefore, tissue from the mucosa and submucosa of the caecum of horses collected from a licenced abattoir was treated to determine whether inhibited cyathostomin larvae could be extracted. The optimum time on full power for a 10-g sample was 20 min, and in three out of five caecal samples from different horses, significantl...
Efficacy of moxidectin against cyathostomins after long-term use in a large herd of draught horses with a high stocking density. This study was undertaken to determine whether resistance to moxidectin had developed in a large herd of draught horses, maintained on a small acreage, which had been routinely treated with moxidectin for five years. Faeces were collected for egg counts immediately before moxidectin gel was administered orally, and seven, 30, 60 and 90 days later. The faecal egg counts were significantly reduced at seven and 30 days after treatment, but were not significantly different from pretreatment counts at 60 and 90 days after treatment. There was no evidence of resistance having developed.
Biological control of horse cyathostomin (Nematoda: Cyathostominae) using the nematophagous fungus Duddingtonia flagrans in tropical southeastern Brazil. The viability of a fungal formulation using the nematode-trapping fungus Duddingtonia flagrans was assessed for the biological control of horse cyathostomin. Two groups (fungus-treated and control without fungus treatment), consisting of eight crossbred mares (3-18 years of age) were fed on Cynodon sp. pasture naturally infected with equine cyathostome larvae. Each animal of the treated group received oral doses of sodium alginate mycelial pellets (1g/(10 kg live weight week)), during 6 months. Significant reduction (p<0.01) in the number of eggs per gram of feces and coprocultures was foun...
Comparative long-term efficacy of ivermectin and moxidectin over winter in Canadian horses treated at removal from pastures for winter housing. The impact of a late fall treatment on the spring rise of fecal egg counts was evaluated in a controlled study with Canadian horses treated with 2 different dewormers immediately after removal from pasture for winter housing. The horses were stabled until the end of the trial period. Seventeen weanlings, 20 yearlings, and 15 2-year-old horses located in Ontario, which were presumed to be naturally infected with cyathostomins after pasture grazing, were randomly allocated to either a group treated with 0.4 mg/kg of moxidectin and 2.5 mg/kg of praziquantel or a group treated with 0.2 mg/kg of iv...
In vitro development of cyathostomin larvae from the third stage larvae to the fourth stage: morphologic characterization, effects of refrigeration, and species-specific patterns. A mixed population of equine cyathostomin (Nematoda, Strongyloidea) infective third stage larvae (L3) was cultured in vitro using a cell-free medium. Some L3 were cultured immediately after Baermann collection from fecal cultures, while others were kept in water at 4 degrees C for 7 days before initiating the in vitro cultures. Cultures were examined daily for viability. At days 2, 7, 14 and 21 larvae were collected for identification of developmental stage and morphological changes, using both light and scanning electron microscopy. Larvae were classified as early L3 (EL3), developing L3 (DL3...
Comparison of two fecal egg recovery techniques and larval culture for cyathostomins in horses. To compare the McMaster and centrifugal flotation techniques and larval culture for recovery of cyathostomin (small strongyle) eggs from the feces of horses. Methods: Fecal samples from 101 horses. Methods: In experiment I, homogenized fresh feces from a single horse were randomly subsampled by use of each technique for 10 replicates. In experiment II, samples from 43 horses that had no anthelmintic treatment were analyzed by use of McMaster, centrifugal flotation, and larval culture techniques. In experiment III, 57 horses were treated with an anthelmintic by owners, and fecal samples were an...
Morphometric identification of equid cyathostome (Nematoda: Cyathostominae) infective larvae. The prevalence of infection with cyathosthomes of horses is high worldwide. Identification of species on infective larvae based on available morphological keys is not fully accurate and the aim of the present study was to provide a reliable identification key of cyathostomes infective larvae. At the abattoir, horse large intestines were examined and the cyathostomes females extracted and identified. The eggs from uteruses of identified cyathostomes females were used for breeding the infective larvae. Morphological parameters of Cyathostominae infective larvae, i.e. the length of the larvae wit...
The little-known scenario of anthelmintic resistance in equine cyathostomes in Italy. Cyathostomes (Nematoda, Cyathostominae) cause colic, decreased performance and growth, peripheral edema, and dysorexia in equids. Also, the synchronous emergence of cyathostome larvae encysted in the colon and cecal wall causes larval cyathostominosis, which is characterized by protein-depriving enteropathy, chronic diarrhea, edema, weight loss, colitis, and may be fatal. In the past few decades, drug resistance in cyathostomes has become widespread, especially for benzimidazoles. Resistance to tetrahydropyrimidines is still confined to a few areas, and the recent reports of reduced efficacy i...
Morphology and diagnosis of some fourth-stage larvae of cyathostomines (Nematoda: Strongyloidea) in donkeys Equus asinus L. from Ethiopia. Fourth-stage larvae of four species of the Cyathostominae Nicoll, 1927 parasitic in donkeys Equus asinus L. from Ethiopia were identified mainly using moulting specimens. They are Cylicocyclus asini Matthee, Krecek & Gibbons, 2001, C. auriculatus (Looss, 1900) Chaves, 1930, Cyathostomum tetracanthum (Mehlis, 1831) Molin, 1861 (sensu Looss, 1900) and Cylindropharynx brevicauda Leiper, 1911. The larva of Cylicocyclus asini is similar to those of C. nassatus (Looss, 1900) Chaves, 1930 and C. leptostomum Kotlán, 1920, but differs from the former by the shape of the dorsal tooth in the oesopha...
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 ...
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 cyathostom...