Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Strongylus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1987

Prevalence of internal parasites in horses in critical tests of activity of parasiticides over a 28-year period (1956-1983) in Kentucky.

The prevalence and number of naturally acquired gastrointestinal parasites were compiled for horses used in critical tests of activity of parasiticides over a 28-year period (1956-1983). Data are presented as follows: n = number of horses examined; % = mean prevalence; number in parentheses after % = aggregate mean number of parasites in infected horses. Parasites found were: bots (n = 513) - Gasterophilus intestinalis, 2nd instar, 61%(58); 3rd instar, 94%(168); G. nasalis, 2nd instar, 36%(28); 3rd instar, 81%(51); stomach worms (n = 200) - Habronema muscae, 65%(179); Draschia megastoma, 29%(95); Trichostrongylus axei, 46%(3000); ascarids (n = 513) - Parascaris equorum, mature, 50%(25); immature, 23%(33); tapeworms (n = 513), Anoplocephala perfoliata, 17%(15); A. magna, 14%(10); large strongyles (n = 487), Strongylus vulgaris, 84%(80); S. edentatus, 79%(101); S. equinus, 6%(14); small strongyles (n = 210), 100%(142,000); pinworms (Oxyuris equi), immature (n = 210), 78%(9000); mature (n = 506), 40%(62); Probstmayria vivipara (n = 210), 12%(10(7]; S. vulgaris in cranial mesenteric artery (n = 472), 89%(57). The majority of the horses examined were mixed lighthorse type but several Thoroughbreds were included. Ages varied from about 4 months to 20 years old, with most being approximately 1-3 years old. They probably had either no or infrequent previous treatment with parasiticides. Most of the horses were selected for presence of certain internal parasites, usually large strongyles, prior to usage in the critical tests.

Animals↗
PubMed1995

Controlled efficacy study of the bioequivalence of Strongid C and generic pyrantel tartrate in horses.

The bioequivalence of Strongid C and generic pyrantel tartrate was determined in a controlled study using 30 horses with naturally acquired endoparasitic infections. Three horses were randomly allocated to each of ten replicates based on quantitative nematode and ascarid egg counts and fecal larvae culture results. Horses within each replicate were randomly assigned to one of three treatment groups. Horses in Treatment Group 1 received only oats; horses in Treatment Group 2 received generic pyrantel tartrate pellets (2.65 mg pyrantel tartrate kg-1) mixed with oats; horses in Treatment Group 3 were fed Strongid C pellets (2.65 mg pyrantel tartrate kg-1) mixed with oats. Horses were treated daily for a 30 day continuous treatment period. At the termination of the study the horses were necropsied and endoparasites recovered, identified, and enumerated. In all instances, no significant difference (P > 0.05) in mean numbers of parasites recovered existed between horses treated with generic pyrantel tartrate and Strongid C. Numbers of gastrointestinal parasites recovered from horses treated with generic pyrantel tartrate or Strongid C were shown to be significantly different (P < 0.05) from numbers of gastrointestinal parasites recovered from non-treated controls for the large strongyles (Strongylus vulgaris, S. edentatus, and Triodontophorus spp.), small strongyles (Cyathostomum spp., Cylicocyclus spp., and Cylicostephanus spp.) and fourth-stage Parascaris equorum. Numbers of adult P. equorum recovered from horses treated with Strongid C were also significantly different (P < 0.05) from those from non-treated controls. Numbers of adult P. equorum recovered from horses treated with generic pyrantel tartrate were not significantly different (P = 0.0761) from those from non-treated controls. The determination of bioequivalence was based upon the 95% confidence interval of the difference between the mean number of parasites recovered from horses treated with generic pyrantel tartrate and the mean number of parasites recovered from horses treated with Strongid C. For all instances in which the numbers of parasites recovered from horses treated with either Strongid C or generic pyrantel tartrate were significantly different from the numbers of parasites recovered from non-treated controls, bioequivalence was demonstrated.

Animal Husbandry↗
PubMed1994

Comparative efficacy of moxidectin and ivermectin against hypobiotic and encysted cyathostomes and other equine parasites.

Efficacies of moxidectin and ivermectin were compared in four groups of eight ponies with natural parasite infections: placebo (Control), oral moxidectin gel at 0.3 mg kg-1 of body weight (Mox 0.3), oral moxidectin gel at 0.4 mg kg-1 of body weight (Mox 0.4), and oral ivermectin paste at 0.2 mg kg-1 of body weight (Ivermectin). Fecal samples were taken 0 and 2 weeks after treatment. Animals were necropsied and worms were collected 2 weeks after treatment. Moxidectin and ivermectin showed similar efficacy (99%) against adult cyathostomes, Strongylus spp., Triodontophorus spp. and Habronema muscae. Both drugs were also more than 98% effective against luminal cyathostome and Oxyuris equi fourth stage larvae (L4). Neither drug was effective (0-10.1%) against hypobiotic early third stage cyathostome larvae (EL3). Moxidectin was moderately effective (62.6-79.1%) in removing encysted cyathostome late third stage larvae (LL3) and L4, whereas ivermectin was ineffective (0%) against these stages. By contrast, ivermectin was 95.4% effective against Gasterophilus spp. third instar stage, whereas moxidectin was only 0-20.4% effective.

Animals↗
PubMed2001

Evaluation of the specificity of five oligoprobes for identification of cyathostomin species from horses.

Here, we report evaluation of five oligoprobes designed from intergenic spacer (IGS) region sequences for identification of cyathostomin species. Oligoprobes were designed for identification of Cylicocyclus ashworthi, Cylicocyclus nassatus, Cylicostephanus longibursatus, Cylicostephanus goldi and a fifth probe designed to identify all members of this tribe. PCR amplification of IGS DNA from 16 cyathostomin species allowed sequence comparison and identification of four putative species-specific probes. Southern blotting of amplified products from 16 species showed that all probes were species-specific. The fifth probe recognised all 16 cyathostomin species but did not bind to members of the genus Strongylus. Furthermore, these probes were used to identify individual infective L3, eggs and L4 indicating that they will be invaluable to furthering the study of the epidemiology and pathogenesis of these important equine nematodes.

Animals↗
PubMed2000

Prevalence of selected species of internal parasites in equids at necropsy in central Kentucky (1995-1999).

A survey to determine current prevalence of several species of endoparasites in equids (n=350) at necropsy was conducted at the Livestock Disease Diagnostic Center in central Kentucky (1995-1999). Thelazia lacrymalis were found in 42% of the 1- to 4-year olds (n=132), which was the only age group examined for these parasites. Five- to 30-year olds (n=157), examined for Onchocerca spp. worms/lesions, had a prevalence of 24%. In > or =1-year olds (n=324), the infection rate for Gasterophilus intestinalis was 12% for second instars and 14% for third instars and for Gasterophilus nasalis was 2% for second instars and 2% for third instars. For Anoplocephala perfoliata (n=268 equids), prevalence was 52%. Data were compiled for the equids according to breed, age, sex, month of necropsy, and number of parasites. Arterial lesions caused by migrating Strongylus vulgaris larvae were observed in a low number (3 of 52) of equids. Specific examination for Parascaris equorum revealed that 46% of 13 weanlings and 10% of 20 older horses were infected. Anoplocephala magna were found in one of the weanlings. Compared to previous studies (about 15-25 years ago) in Kentucky, the present survey indicated the genera Onchocerca and Gasterophilus greatly declined but Thelazia, Anoplocephala, and Parascaris did not.

Animals↗
PubMed2001

Re-evaluation of ivermectin efficacy against equine gastrointestinal parasites.

Two trials were conducted to confirm the efficacy of ivermectin paste against endoparasites of horses. In these trials, 20 ponies were treated with ivermectin oral paste at 200 mcg x kg body weight once on Day 0, and 20 ponies served as unmedicated controls. The animals carried naturally acquired parasite infections as confirmed by pretrial fecal examination. The animals were necropsied for worm recovery on Days 14, 15 or 16. Parasites recovered were identified to species. Horses treated with ivermectin had significantly (P<0.05) fewer (>99.0% reduction) adult small strongyles (Coronocyclus spp including C. coronatus, C. labiatus, C. labratus; Cyathostomum spp including C. catinatum, C. pateratum; Cylicocyclus spp including C. ashworthi, C. elongatus, C. insigne, C. leptostomum, C. nassatus, C. radiatus; Cylicodontophorus bicoronatus; Cylicostephanus spp including C. asymetricus, C. bidentatus, C. calicatus, C. goldi, C. longibursatus, C. minutus; Gyalocephalus capitatus; Parapoteriostomum spp including P. euproctus, P. mettami; Petrovinema poculatum; Poteriostomum spp including P. imparidentatum, P. ratzii) and adult large strongyles (Strongylus edentatus, S. vulgaris; Triodontophorus spp including T. brevicauda, T. serratus; Craterostomum acuticaudatum) than the controls. Ivermectin was also highly effective (94% to >99%, P<0.05-0.01) against Gasterophilus intestinalis larvae, Habronema spp., Oxyuris equi, Parascaris equorum. The data from these two trials confirm that ivermectin paste administered to horses orally at 200mcg x kg(-1) continues to be highly effective for treatment and control of a broad range of small and large strongyle species as well as other species of gastrointestinal parasites.

Administration, Oral↗
PubMed1997

Controlled dose confirmation study of a 2% moxidectin equine gel against equine internal parasites in The Netherlands.

The efficacy of a 2% moxidectin equine gel at a dosage rate of 0.4 mg kg-1 was evaluated in a controlled trial at Utrecht University. Twelve yearling castrated male Shetland ponies grazed a pasture of 2 ha from May 1994 until housing in November. Six ponies were treated with moxidectin, whereas the others served as non-treated controls. Necropsy was carried out 35 days after treatment. Greater than 99% efficacy of moxidectin was observed on faecal egg output. No effect of moxidectin was observed on mucosal inhibited early cyathostome L3 (EL3) or on the total numbers of mucosal developing stages. However, a 89.6% reduction was observed on large mucosal fourth stage larvae (L4). Moxidectin treatment probably triggered resumption of development of EL3. Moxidectin appeared to be highly effective (95-100%) on lumenal L4 cyathostomes, adult strongylids, Strongylus vulgaris larvae from the arteries, S. edentatus larvae from the abdominal wall and Trichostrongylus axei. Moxidectin had relatively poor efficacy against Gasterophilus intestinalis and had no effect on Anoplocephala perfoliata. No side-effects of moxidectin treatment were observed.

Animals↗
PubMed1977

An evaluation of ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) for anthelmintic activity in domestic animals.

Ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens. Sixteen critical trials were conducted in ponies at dosages of 15 to 150 mg/kg. At 15 mg/kg, efficacy against adult and larval Oxyuris equi was 100% and 91% and against small strongyles it was 98%. Efficacy levels were 95% against Strongylus vulgaris and S. edentatus at the 20 mg/kg dosage. In two trials at 100 mg/kg efficacy against Parascaris equorum was 77%. No efficacy was observed against Gastrophilus spp. or Anoplocephala spp. In swine single oral doses of 10 to 100 mg/kg were not effective. 500 ppm Sch 18099 in the diet for seven days resulted in 100% efficacy against Ascaris suum and Trichuris suis but had no effect on Stongyloides ransomi. Efficacy at 250 ppm against A. suum was 77%. Efficacy at 200 mg/kg in lambs was greater than 90% for Haemonchus contortus, Trichostrongylus axei, Marshallagia marshalli, Bunostomum trignocephalum, Oesophagostomum columbianum, Trichuris ovis, and Chabertia spp. Efficacy was less than 80% for Trichostrongylus vitrinus, Nematodirus filicollis, Ostertagia circumcinta and Cooperia curticei. Except for O. circumcinta and C. curticei, drug efficacy was reduced for these worms in lambs treated at 100 mg/kg. Efficacies of 14.3-89% against Ascaridia galli were obtained with dietary levels of 125-1000 ppm Sch 18099 fed for 7 days. Efficacy of 100% was recorded against Heterakis gallinarum at the 1000 ppm dietary drug level.

Animals↗
PubMed1995

The evolution of tissue migration by parasitic nematode larvae.

Migration by nematode larvae through the tissues of their mammalian hosts can cause considerable pathology, and yet the evolutionary factors responsible for this migratory behaviour are poorly understood. The behaviour is particularly paradoxical in genera such as Ascaris and Strongylus in which larvae undergo extensive migrations which begin and end in the same location. The orthodox explanation for this apparently pointless behaviour is that a tissue phase is a developmental requirement following the evolutionary loss of skin penetration or intermediate hosts. Yet tissue migration is not always necessary for development, and navigation and survival in an array of different habitats must require costly biochemical and morphological adaptations. Migrating larvae also risk becoming lost or killed by the host. Natural selection should therefore remove such behaviour unless there are compensating benefits. Here we propose that migration is a selectively advantageous life-history strategy. We show that taxa exploiting tissue habitats during development are, on average, bigger than their closest relatives that develop wholly in the gastrointestinal tract. Time to reproduction is the same, indicating that worms with a tissue phase during development grow faster. This previously unsuspected association between juvenile habitat and size is independent of any effects of adult habitat, life-cycle, or host size, generation time or diet. Because fecundity is intimately linked with size in nematodes, this provides an explanation for the maintenance of tissue migration by natural selection, analogous to the pre-spawning migrations of salmon.

Animals↗
PubMed1999

Species-specific amplification by PCR of ribosomal DNA from some equine strongyles.

The first and second internal transcribed spacer sequences of 28 morphologically-defined species of horse strongyle were characterized, and specific oligonucleotide primers were designed for some species based on the nucleotide differences. Utilizing these primers, a PCR approach was developed for the specific amplification of ribosomal DNA of Strongylus vulgaris, Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus or Cylicostephanus goldi. The method allowed the species-specific amplification of parasite DNA derived from faecal samples and/or copro-cultures, demonstrating the potential of the approach for the diagnosis of equine strongyloidosis. The establishment of this PCR assay also has implications for studying the biology and epidemiology of equine strongyles and anthelmintic resistance using faecal egg count reduction tests.

Animals↗
PubMed2000

The "galloping" history of intermittent claudication.

Intermittent claudication (IC) due to arterial occlusive disease was first diagnosed by the French veterinary surgeon Jean-François Bouley jeune in a horse drawing a cabriolet in the streets of Paris as early as 1831. The animal was repeatedly exercised and always started to limp with the hind legs at similar work loads. Autopsy revealed partially thrombosed aneurysm of the abdominal aorta and occlusions of both femoral arteries which were correctly identified as the cause of IC. In 1858 the famous neurologist Jean-Martin Charcot working at the Salpêtrière in Paris first discovered the condition in a patient, who was wounded by a bullet during the conquest of Algery and developed iliac artery aneurysm obliterated by a thrombus. He was aware of the first description in veterinary medicine. In Germany IC was also first mentioned in horses (Rademacher, 1838). 13 reports of patients were contributed by the neurologist Heinrich Erb in 1898 and 1904. Some interesting features of the phenomenon of IC like the amount of exercise necessary to provoke it, localization, social relevance, prolongation of the Achilles tendon reflex, decrease of maximal plantar flexion force of the foot and production of "Lewis factor p" are summarized. In human patients arteriosclerosis is the well recognized principal cause of arterial obstructions, in horses, however, the lesions are due to infection by the roundworm Strongylus vulgaris. In the fascinating life cycle the larvae migrate into the intima of small and large arteries and provoke aneurysms and intravascular thrombosis.

Animals↗
PubMedDate not supplied

Anthelmintic resistance in nematodes of horses.

Suppressive anthelmintic treatment strategies originally designed to control Strongylus vulgaris in horses were extremely successful in reducing morbidity and mortality from parasitic disease. Unfortunately, this strategy has inadvertently resulted in the selection of drug-resistant cyathostomes (Cyathostominea), which are now considered the principal parasitic pathogens of horses. Resistance in the cyathostomes to benzimidazole drugs is highly prevalent throughout the world, and resistance to pyrantel appears to be increasingly common. However, there are still no reports of ivermectin resistance in nematode parasites of horses despite 20 years of use. It is unknown why resistance to ivermectin has not yet emerged, but considering that ivermectin is the single most commonly used anthelmintic in horses most parasitologists agree that resistance is inevitable. The fecal egg count reduction test is considered the gold standard for clinical diagnosis of anthelmintic resistance in horses, but diagnosis is complicated by lack of an accepted standard for the performance of this test or for the analysis and interpretation of data. Presently there is very little data available on the molecular mechanisms of anthelmintic resistance in cyathostomes; beta-tubulin gene is the only anthelmintic-resistance associated gene that has been cloned. The increasingly high prevalence of anthelmintic-resistant cyathostomes must be taken into account when designing worm control programs for horses. Strategies to decelerate further selection for drug resistance thereby extending the lifetime of currently effective anthelmintics should be implemented whenever possible. Considering the nature of the equine industry in which horses often graze shared pastures with horses from diverse locations, transmission and widespread dispersal of resistant parasites is virtually assured. A proactive approach to this problem centered on understanding the molecular basis of anthelmintic resistance in cyathostomes is required if we are to expect chemical control of nematodes in horses to remain a viable element of parasite control in the future.

Animals↗
PubMed1985

Spinal nematodosis in a donkey with posterior paresis.

Spinal nematodosis in a four-year-old donkey is described. The animal showed progressive hindlimb paresis of sudden onset. Necropsy revealed extensive degeneration and inflammation in the lumbosacral part of the spinal cord, caused by a nematode larva of the suborder Strongylina, probably L4 or L5 of Strongylus vulgaris.

Animals↗
PubMed1993

The reappearance of eggs in faeces of horses after treatment with ivermectin.

The reappearance of nematode eggs in faeces after ivermectin treatment was studied in 104 horses on 10 farms during the stabling period. Faecal samples were taken at weekly intervals. Sampling was discontinued when the mean egg output per farm was > 10% of the pre-treatment egg output. This point was reached after 63 days, when the mean output of eggs had decreased to 70.3%. Before treatment, 95.9% of the cultured larvae were of the cyathostome type, the others belonged to Gyalocephalus capitatus, Strongylus vulgaris, S. edentatus, Oesophagodontus/Poteriostomum spp., Triodontophorus spp. and Trichostrongylus axei. After treatment, the cultures nearly always produced 100% cyathostome larvae, although occasionally low numbers (< 1%) of larvae of large strongyles (mainly S. edentatus, rarely S. vulgaris and Oesophagodontus spp.) and T. axei were seen.

Animals↗
PubMed1991

Equine neural angiostrongylosis.

Verminous encephalomyelitis due to Angiostrongylus cantonensis larvae was diagnosed in 2 foals at necropsy. The principal clinical feature was tetraparesis, although history and neurological examination revealed progressive and multifocal neurological disease. At presentation, a tentative diagnosis of parasitic larval migration involving the central nervous system (CNS), presumably due to Strongylus vulgaris, was proposed. Dissection of the spinal cord in one case resulted in recovery of intact larvae of both sexes of A. cantonensis. In both foals, histopathology of the brain and spinal cord revealed nematode sections which were consistent with A. cantonensis larvae.

Angiostrongylus↗
PubMedDate not supplied

Occurrence of gastrointestinal parasites in horses in metropolitan Perth, Western Australia.

OBJECTIVE: To assess the occurrence of gastrointestinal parasites in horses in Perth. To apply polymerase chain reaction (PCR) for the identification of some species of encysted larval cyathostomes. DESIGN: Between February and September of 2000, the gastrointestinal tracts of 29 horses submitted to a local knackery and Murdoch University Veterinary hospital in Perth were examined post mortem for the presence of gastrointestinal parasites. PROCEDURE: The gastrointestinal tract was divided into six sections, which were screened for the presence of parasites such as Gasterophilus sp, Anoplocephala sp and Parascaris equorum. Samples of contents were taken for worm counts. RESULTS: Cyathostomes were found in 28 of the 29 horses. Eighteen species of gastrointestinal helminths were identified. Twelve of these were cyathostomes, with the four most common species being Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus and Cylicostephanus goldi. The large strongyle, Triodontophorus serratus, was found in three of the horses but species of Strongylus were not found. CONCLUSIONS: In contrast to a study conducted on horses from this region in 1985, cyathostomes were the most common gastrointestinal parasites found. The four most common cyathostome species found in the present study correlated well with findings of studies in other locations. The high number of cyathostomes may be due to the increase in resistance to anthelmintics among the species, and to improper anthelmintic use. The apparent reduction in number of large strongyles may be due to the widespread use of ivermectin, which is very effective against these parasites, and also possibly because some larvae may not have been detected.

Animals↗
PubMed1979

Equine verminous arteritis. An arteriographic evaluation of the larvicidal activity of albendazole.

Albendazole was an effective larvicidal anthelmintic against the fourth stage Strongylus vulgaris larvae as late as one month post-infection. The drug was administered at a dose rate of 25 mg/kg three times daily for 5 days. Diarrhoea occurred in 3 of 4 foals treated and of these one died during belated intravenous therapy for dehydration. Arteriography allowed for an in vivo assessment of the development and regression of lesions in infected-treated foals compared to the continued development of lesions in infected-untreated foals. The arteriographic findings were confirmed at necropsy.

Albendazole↗
PubMed1981

Ischaemic myocardial fibrosis and aortic strongylosis in the horse.

The hearts and aortas of 2076 unselected horses of all ages were examined immediately after slaughter. Focal zones of fibrosis, observed in the myocardium of 14.3 per cent of hearts examined, were found in both atria and ventricles and were unrelated to age. Microscopically the majority of lesions involved myocardial fibre lysis and replacement fibrosis, although acute infarction was present in some cases. Intramyocardial arterioles in or adjacent to the lesions exhibited occlusive arteriosclerotic changes whereas those elsewhere remained patent. The evidence strongly suggests that the myocardial lesions were ischaemic in origin and related to the distribution of intramyocardial arteriosclerosis. Nodular fibrous plaques and mural thrombi associated with migrating larvae of Strongylus vulgaris were observed in the thoracic aorta of 9.4 per cent of horses. These intimal lesions were often present in the aortic bulb and proximal 10 cm of the thoracic aorta indicating that larval migration in this zone is common. Statistical analysis revealed a highly significant association between the occurrence of proximal aortic S vulgaris lesions and the presence of focal ischaemic lesions in the myocardium. The association was not the result of direct larval damage but appeared to be caused by microembolisation from parasitic lesions in the proximal aorta, producing obstructive arteriosclerotic lesions in myocardial arterioles.

Animals↗