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.
The distribution of inhibited early third stage Cyathostominae larvae in the large intestine of the horse. The distribution of inhibited early third stage Cyathostominae larvae in different parts of the large intestine of the horse was studied in 20 Shetland ponies necropsied in autumn 1982, 1983 and 1984. The location of the larvae in the large intestinal wall was studied by histological examination of the intestines of the eight ponies from 1984. Inhibited larvae were located predominantly and more or less equally in the caecum and the ventral colon. Generally fewer early L3 were in the dorsal colon. In 1984 a considerable proportion (mean 17%, range 9.7-36.9%) of the inhibited larvae was found i...
Seasonal changes in pasture infectivity by equine cyathostomes in north central Florida. ALTHOUGH the seasonal transmission of equine cyathostomes is well documented in cool climates (Ogbourne 1978),
less is known about their transmission in warm climates.
Australian studies have suggested that these parasites do not
survive well during the long, hot summers of the humid
subtropics (English 1979a.b). Development of egg to third
stage larva (L3) was rapid during the summer but the
percentage of larvae that survived to ascend herbage was very
low. In contrast, larvae survived for longer periods during the
cooler months and the highest L3 populations were observed
during spr...
Larval cyathostomiasis (immature trichonema-induced enteropathy): a report of 15 clinical cases. Clinical and laboratory findings are recorded from a series of 15 cases (aged one to 16 years) of sudden-onset chronic diarrhoea with weight loss, progressing in many cases to emaciation and death, associated with the emergence of fourth stage cyathostome (trichoneme) larvae in large numbers through the colonic and caecal mucosae. Apart from a single incident in mid-October, disease only occurred in winter and spring (January to May). Characteristic features included hypoalbuminaemia, increased alpha and beta plasma globulin levels and neutrophilia without left shift. Faecal egg counts were fr...
Inhibited development of cyathostominae in the horse in the early third stage. Inhibited early third stage larvae of Cyathostominae were found in the digested mucosa of the large intestine of 12 yearling, female Shetland ponies, which were used in two grazing experiments. The ponies were killed in late autumn. In some ponies the inhibited larvae were very abundant and in most animals the majority of the Cyathostominae populations consisted of these early third stage larvae, suggesting that the phenomenon has an epidemiological significance.
Granulomatous colitis associated with small strongyle larvae in a horse. Horses presented with chronic weight loss are difficult to manage clinically. A diagnosis of granulomatous colitis due to mucosal stages of cyathostomes (small strongyles) should be considered in those cases exhibiting weight loss, intermittent diarrhea, hypoalbuminemia, increased serum globulins, and low fecal egg counts. Treatment can be attempted with larva-cidal doses of fenbendazole or ivermectin. Clinical and necropsy findings in one such case are presented.
Control of cyathostome infections in mares treated at parturition with ivermectin. Six mares were treated on the day of parturition with an intramuscular injection of 0.2 mg kg-1 ivermectin and placed in a pasture free of equine parasites as soon as possible after foaling. The mares and their foals were compared with a similar group of untreated mares and foals on an adjoining pasture. The experimental data was derived from mare and foal fecal egg counts, foal necropsies and pasture larval counts. Ivermectin administered to mares on the day of parturition, when combined with movement to parasite-free pastures, significantly lowered the cyathostome (small strongyle) egg produ...
The prevalence and intensity of internal parasites of horses in the U.S.A. Fifty-five adult horses were necropsied over a 15-month period, and their worm burdens counted and speciated. Twenty-one species of Cyathostominae were recovered. Ten species: Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus, Cyathostomum coronatum, Cylicostephanus goldi, C. calicatus, C. minutus, Cylicocyclus leptostomus, C. insigne and Cyathostomum pateratum, comprised 98.9% of the total cyathostome burdens. These same 10 species also demonstrated high prevalences in 4 previous surveys. Eight of these 10 species have been shown to be resistant to benzimidazole ant...
Transmission of equine cyathostomes (Strongylidae) in central Texas. After foaling, 6 mares and their foals were placed on equine parasite-free pastures. Observations of fecal nematode eggs and pasture larvae indicated peak cyathostome egg production occurred in late August and early September, with greatest numbers of larvae on the forage appearing during October. Two foals were necropsied for parasitologic evaluations at approximately 155 days of age. Both had approximately 100,000 adult cyathostomes, mostly Cylicostephanus longibursatus, Cylicocyclus nassatus and Cyathostomum catinatum. However, there were nearly 7 times more cyathostome larvae (189,004) in ...
Alternate grazing of horses and sheep as control for gastro-intestinal helminthiasis in horses. Gastro-intestinal helminth infections of a group of three yearling mare Shetland ponies, which were set-stocked on a small pasture from February until September, were compared with those of a similar group of ponies, which grazed a similar pasture from February to July and subsequently was removed to a pasture which had been grazed by sheep from April to July. In addition both groups were treated with cambendazole when the latter group was removed to the sheep pasture. Pasture larval counts and worm counts demonstrated that the group grazed after the sheep acquired considerably smaller burdens...
Critical tests in equids with fenbendazole alone or combined with piperazine: particular reference to activity on benzimidazole-resistant small strongyles. Seven critical tests in equids were conducted with single doses of fenbendazole (5 mg kg-1) alone (Panacur--American Hoechst, Somerville, NJ); (2 tests with paste and 1 with suspension formulation) or in combination with piperazine (American Hoechst); (40 mg base kg-1); (4 tests with paste formulation). The main purpose of the tests was evaluation of activity against benzimidazole-resistant small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus). Natural infections of 2 populations of benzimidazole-resis...
Cyathostominae and other strongyles of horses in the Federal Republic of Germany. The faeces of 34 horses of the "Bavarian main and state studfarm Schwaiganger" (Group I) and 10 ponies (Group II) from various regions of the Federal Republic of Germany, were examined and 4 834 small strongyles were identified. Three species Cyathostomum catinatum, Cylicostephanus longibursatus and Cylicocylus nassatus, were found to be widely distributed. Although various modern anthelmintics with different effective components were used over the past 20 years, no remarkable change has been brought about in the composition of the parasitic species of the horses in the Federal Republic of Ger...
Ivermectin as an antiparasitic agent in horses. Ivermectin, described as 22,23-dihydroavermectin B1, was the compound chosen from the avermectin group of compounds for development as an antiparasitic agent in horses. A review of the literature indicates that parenteral administration in horses at 200 microgram/kg body mass is highly effective against the strongyles Strongylus vulgaris, Strongylus edentatus and triodontophorus spp., and adult and immature cyathostomes, including strains resistant to benzimidazole anthelmintics. Other nematodes controlled in horses include Oxyuris equi, Parascaris equorum, Trichostrongylus axei, and Habronema...
Anthelmintic efficacy of ivermectin given intramuscularly in horses. The anthelmintic activity of ivermectin was evaluated in 18 female horses with naturally acquired parasitic infections. Horses were treated once (IM) with vehicle only (n = 6), 200 microgram/kg of body weight (n = 6), and 300 microgram/kg (n = 6). Efficacy of both dosages of ivermectin was greater than 99% against Gasterophilus spp, 100% against Trichostrongylus axei, Habronema muscae, H majus, and Draschia megastoma, 98% to 99% against adult cyathostomes, 86% to 97% against 4th-stage cyathostomes, and 100% against adult large strongyles. Although ivermectin was incomplete in its activity agai...
Controlled evaluation of ivermectin in Shetland ponies. Ivermectin was injected IM into 12 yearling Shetland ponies. The following reactions in percentages of parasites recovered from ponies given 200 microgram/kg or 300 microgram/kg, as compared with the parasitic population in those given the vehicle at 1 week after injection, were as follows: Otobius megnini nymphs--no reduction; Gasterophilus intestinalis--100% and 99.9%; G nasalis--100% and 99.9%; Parascaris equorum adults--100% and 96%; Strongylus vulgaris adults--100% and 100%; S edentatus adults--100% and 100%; cyathostome adults of the genera Gyalocephalus, Cylicocyclus, Cyathostomum, Cyli...
Anthelmintic efficacy fenbendazole paste in equines. A single oral dose of fenbendazole (FBZ) paste at 7,5 mg/kg body mass was given to 5 horses. It was highly effective against adults of the following genera: Cyathostomum, Cylicostephanus, Cylicondontophorus, Poteriostomum, Cylicocyclus, Triodontophorus, Oesophagodontus (and other genera belonging to the subfamily Cyathostominae). Similarly, high efficacy was obtained against the adults of the following species: Oxyuris equi, Strongylus vulgaris, Strongylus equinus and Probstmayria vivipara. These results were confirmed in 12 horses and in addition FBZ at 7,5 mg/kg was highly effective against ...
Resistance to benzimidazole anthelmintics in equine strongyles. 2. Evidence of side-resistance, and susceptibility of benzimidazole-resistant strongyles to non-benzimidazole compounds. The susceptibility of a known thiabendazole-resistant population of small strongyles to anthelmintics of both benzimidazole and non-benzimidazole groups, was determined. In the first study, 42 horses infected with thiabendazole-resistant small strongyles were allocated to 6 groups. Treatment groups received one of the following anthelmintics: mebendazole, febantel, febantel plus trichlorphon, morantel tartrate, or a combination of thiabendazole, piperazine and trichlorphon. Morantel tartrate and the thiabendazole/piperazine/trichlorphon combination produced highly significant (p less than 0.00...
A critical efficacy test of cambendazole in equids: the use of the geometric means to assess efficacy. The anthelmintic efficacy of a 44.5% paste formulation of cambendazole was evaluated in a critical trial performed on 5 horses and a donkey. A dosage of 20 mg/kg showed reduction of mean parasite burdens as follows: Strongylinae greater than 99%; Cyathostominae 94%; immature and adult Oxyuris equi 89 and greater than 99%; Probstmayria vivipara greater than 99% and Habronema muscae 97%. Parascaris equorum and Anoplocephala perfoliata were present in small numbers in individual animals only, and while all were removed by treatment, the small numbers did not justify calculation of a percentage ef...
Anthelmintic efficiency of fenbendazole in equines. A single oral dose of fenbendazole (FBZ) at 10mg/kg body mass was given to 5 donkeys. A further 5 donkeys were dosed with a medicated lick (1 mg FBZ/g lick) until the oral consumption was 10mg/kg body mass. In both trials FBZ was highly effective against adults of the following genera: Cyathostomum, Cylicocyelus, Cylicostephanus, Cylicodontophorus, Poteriostomum, Cabellonema, Craterostomum and Triodontophorus; similarly high efficiency was obtained against the following species: Habronema majus, Habronema musca, Strongylus vulgaris and Oxyuris equi and worms identified as belonging to the subf...
Anthelmintic efficiency of fenbendazole in equines. A single oral dose of fenbendazole (FBZ) at 10 mg/kg body mass was given to 5 donkeys. A further 5 donkeys were dosed with a medicated lick (1 mg FBZ/g lick) until the oral consumption was 10 mg/kg body mass. In both trials FBZ was highly effective against adults of the following genera: Cyathostomum, Cylicocyclus, Cylicostephanus, Cylicodontophorus, Poteriostomum, Cabellonema, Craterostomum and Triodontophorus; similarly high efficiency was obtained against the following species: Habronema majus, Habronema musca, Strongylus vulgaris and Oxyuris equi and worms identified as belonging to the su...
Benzimidazole resistance of equine stronygles–critical tests of six compounds against population B. Critical tests were conducted on eight horses naturally infected with several species of large and small strongyles from population B. Tested were six benzimidazoles, including thiabendazole (2 lots) (44 mg/kg of body weight); mebendazole (8.8 mg/kg); cambendazole (two formulations) (20 mg/kg); fenbendazole (10 mg/kg); oxibendazole (10 mg/kg); and oxfendazole (10 mg/kg). All compounds were administered by stomach tube except one of the two cambendazole formulations which was an intraoral paste. Removal of large strongyles (when present), Strongylus vulgaris and Strongylus edentatus, was 100% b...
Critical anthelmintic trials in ponies with oxfendazole and caviphos and concomitant studies on the spontaneous elimination of small strongylids. The efficacy of the benzimidazole, oxfendazole, and the organophosphate, caviphos, against gastrointestinal parasites of ponies was evaluated by the critcial test method. Oxfendazole (10 mg/kg of body weight) given in single oral doses was 100% effective against adult large strongylids (Strongylus vulgaris, Strongylus edentatus, and Strongylus equinus), 99% effective against adult small strongylids, and 97% effective against 4th-stage small strongylids (genera identified in order of frequency: Cylicostephanus, Cyathostomum, Cylicocyclus, Triodontophorus, Poteriostomum, Oesophagodontus, Cylicod...
[Cyathostominosis: a form of severe strongylidosis (author’s transl)]. A form of strongyle infection in young horses and ponies, observed during the period from November to May, is described. Large numbers of larvae of Cyathostominae in the fourth or early fifth stage of development are found to be present in the (often watery) faeces. This excretion of larvae is not affected by treatment with anthelmintics. A large number of these patients die from the sequelae of verminous enteritis.
Critical anthelmintic trials in ponies with four benzimidazoles: mebendazole, cambendazole, fenbendazole, and albendazole. The comparative efficacy of four benzimidazoles against gastrointestinal parasites of ponies was evaluated by the critical test method. Mebendazole (8.8 mg/kg), cambendazole (20 mg/kg), fenbendazole (5 mg/kg), and albendazole (2.5 and 5 mg/kg) given in single oral doses were highly effective against adult large strongylids (Strongylus vulgaris, S. endentatus, S. equinus) and adult small strongylids (genera identified in order of frequency: Cylicostephanus, Cylicocyclus, Cyathostomum, Triodontophorus, Poteriostomum, Oesophagodontus, Cylicodontophorus, Gyalocephalus, and Craterostomum). Limited ...
The prevalence, relative abundance and site distribution of nematodes of the subfamily Cyathostominae in horses killed in Britain. A total of 21 species of Cyathostominae was found in the lumen of the large intestine of 86 mature horses of various ages and breeds killed in south-west England during 1972-1974. Cylicostephanus longibursatus, C. goldi, C. calicatus, Cyathostomum catinatum, C. coronatum and Cylicocyclus nassatus were found in over 80% of the horses, while 12 of the remaining species were detected in less than 30%. Quantitative studies on 55 horses showed the adult cyathostome burdens to rise to a sharp peak (average over 400,000/horse) in April-June and a lower one in November-December. Parallel fluctuations ...
Critical tests with oxibendazole against gastrointestinal parasites of ponies. Twenty ponies were allotted to 4 groups of 5 ponies each, and oxibendazole was orally administered at dose levels of 5, 10, 15, and 20 mg/kg. In the 3 groups of ponies given the largest doses, efficacy against 3 species of Strongylus was between 92 and 100% and that against small strongylids of the genera Cyathostomum, Cylicocyclus, Cylicodontophorus, and Cylicostephanus was more than 99%. All adults and 95 to 100% of larvae of the pinworm Oxyuris equi were removed. In the group of ponies given 5 mg/kg, 86 to 100% of the large strongylids and 84 to 100% of the small strongylids were removed, a...