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Topic:Parasites
Parasites are organisms that live on or within a host, deriving nutrients at the host's expense. In horses, parasitic infections can affect various systems, including the gastrointestinal tract, skin, and respiratory system. Common equine parasites include strongyles, ascarids, tapeworms, and bots. These parasites can lead to a range of health issues, from mild discomfort to severe disease, depending on the type and burden of the infestation. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, life cycle, and impact of parasites on equine health, as well as strategies for diagnosis, treatment, and prevention of parasitic infections in horses.
Activity of praziquantel (0.5 mg kg-1) against Anoplocephala perfoliata (Cestoda) in equids. Praziquantel injectable formulation was administered at 0.5 mg k-1 per os to 24 equids naturally infected with 1-183 (average 40) Anoplocephala perfoliata. Drug activity was evaluated by a modified critical test method with necropsy 24 h after treatment. There was variable efficacy of 0-100% (aggregate average 85%); for 18 equids, 93-100%, for three equids, 70-85%, and for three equids, 0-20%.
Equine parafilariosis in Iran. From March to September 1991, horses (n = 1567), donkeys (n = 112) and mules (n = 96) were examined for equine parafilariosis by random sampling from different areas of Iran. The clinical signs of equine parafilariosis were observed in 136 cases of two northern areas (1.4% and 41.3% infection rate) and one northeastern area (6.3% infection rate). Most of the infected cases were confirmed by laboratory findings. All infected cases were followed up to establish the epidemiological features. The results suggest that there is one enzootic area in Iran, the Caspian coast and Persian Turkman steppes...
Prevalence of botfly larvae and lice in studs of North Caucasus (Stawropol County, Russia). From 14 to 17 April 1990 and from 12 to 21 May 1993 a total of 136 Caucasian (Donish, Karabakh, Kabardin, local halfbred) and 26 thoroughbred stud-horses were examined for ectoparasites in studs of Stawropol County, Russia. A total of 4054 botfly larvae were identified from 9700 faecal samples collected during a period of 3-4 days after oral treatment with Eqvalan (MSD), Strongid Plus (Pfizer) and Vermitan Plus (Sanofi-Chinoin). The species distribution was: Gasterophilus intestinalis 84.53%, G. nasalis 10.41%, G. haemorrhoidalis 3.62%, G. inermis 1.41%. Gasterophilus nasalis and G. inermis ha...
Anoplocephala perfoliata in horses in Sweden: prevalence, infection levels and intestinal lesions. Distal ileum, caecum and proximal colon of 470 horses were examined for helminths during 1 year at an abattoir in central Sweden. The infection levels of the horse tapeworm Anoplocephala perfoliata, their stage of development, site of attachment and gross pathological lesions caused by the worm were recorded. Faecal samples from 395 of the horses were examined specifically for tapeworm segments and eggs in order to correlate these findings with the numbers in the alimentary canal. In total 65% of the horses were infected with A. perfoliata and the mean intensity of infection was 79 worms per i...
[Preliminary results using a combined xylose absorption/hydrogen exhalation test in horses]. In the present study the breath hydrogen (H2) excretion test was combined with the xylose absorption test in 4 normal horses and 9 clinical patients with chronic diarrhea (n = 3) or chronic weight loss without diarrhea (n = 6). All horses underwent a thorough clinical examination. Laboratory evaluations consisted of haematology and serum biochemistry as well as bacteriological and parasitological examination of feces. In addition, serum electrophoresis and abdominocentesis was performed in all the clinical patients. Gastroscopy was carried out in 6 patients and rectal biopsies were obtained fr...
In vitro assessment of two species of nematophagous fungi (Arthrobotrys oligospora and Arthrobotrys flagrans) to control the development of infective cyathostome larvae from naturally infected horses. The ability of two species of nematophagous fungi, Arthrobotrys oligospora and Arthrobotrys flagrans (syn. Trichothecium flagrans, Duddingtonia flagrans), to control the development of infective larvae in feces from naturally infected horses was assessed in vitro. The horses were from a farm where it had been previously established that cyathostomes accounted for 100% of the strongyle egg output. The feces from these naturally infected horses were mixed with spores of each fungal species at four concentrations: 0 (control), 1, 10, and 100 spores per egg. Five replicates for each group were inc...
The prevalence and epidemiology of Anoplocephala perfoliata infection in Norway. The caecum and the adjacent 30 cm lengths of ileum and large colon of 201 horses from two different regions of Norway (Ostlandet and Trøndelag) were examined for the presence of Anoplocephala perfoliata. In all, 20% of the horses were infested with the cestode (27% in Ostlandet and 7% in Trøndelag). The mean number of worms in infected horses from the two regions was 18 and 6, respectively. Information was obtained on the age, sex, breed, type of pasture and anthelmintic treatment after the grazing season for 183 of the 20 horses. The degree of infestation with A. perfoliata was not influenc...
[Parasitic horse ticks in Italy. Observations on their distribution and pathogenic role]. The following 13 species of ticks, belonging to Ixodidae family, were recorded in Italy on horse (Equus caballus) since 1931: Ixodes ricinus, I. gibbosus, Haemaphysalis inermis, H. parva, H. punctata, H. sulcata, Dermacentor marginatus, Rhipicephalus sanguineus, Rh. bursa, Rh. turanicus, Hyalomma marginatum, Hy. detritum, Boophilus annulatus. The regional distribution and the role of the species in the transmission of pathogens are reported.
Experimental immunization of ponies with Strongylus vulgaris radiation-attenuated larvae or crude soluble somatic extracts from larval or adult stages. Protection from Strongylus vulgaris infection through immunization with radiation-attenuated third-stage larvae (L3) or crude soluble homogenates from larval or adult stages was examined. Yearling ponies raised parasite-free were divided into 3 immunization groups: radiation-attenuated L3; soluble adult somatic extracts; larval somatic extracts with excretory/secretory products (E/S) from in vitro culture; and 1 medium control group. Ponies were immunized twice; attenuated larvae were administered orally and somatic extracts or controls injected intramuscularly with adjuvant. Approximately 6 w...
Phylogenetic relationship of Sarcocystis neurona to other members of the family Sarcocystidae based on small subunit ribosomal RNA gene sequence. Sarcocystis neurona is a coccidial parasite that causes a neurologic disease of horses in North and South America. The natural host species are not known and classification is based on ultrastructural analysis. The small subunit ribosomal RNA (SSURNA) gene of S. neurona was amplified using polymerase chain reaction techniques and sequenced by Sanger sequencing reactions. The sequence was compared with partial sequences of S. muris, S. gigantea, S. tenella, S. cruzi, S. arieticanis, S. capracanis, Toxoplasma gondii, Eimeria tenella, and Cryptosporidium parvum. Alignments of available sites for ...
Multifocal myositis associated with Sarcocystis sp in a horse. Multifocal myositis was diagnosed in a 7-year-old Quarter Horse gelding on the basis of history and findings on physical examination, serum biochemical analysis, electromyography, and microscopic examination of frozen sections of muscle biopsy specimens. Histologic examination of the muscle specimen revealed multifocal accumulations of histiocytes, lymphocytes, and plasma cells, with attendant myofiber degeneration and necrosis. Parasitic cysts with morphologic characteristics of Sarcocystis sp were found in regions of myocyte degeneration and necrosis, and in regions of normal muscle. Based o...
Investigations on naturally occurring Trypanosoma evansi infections in horses, cattle, dogs and capybaras (Hydrochaeris hydrochaeris) in Pantanal de Poconé (Mato Grosso, Brazil). The prevalence of Mal de Cadeiras--Portuguese for Trypanosoma (T.) evansi infections in horses--as well as the prevalence of T.evansi infections in cattle, dogs and free-ranging capybaras (Hydrochaeris hydrochaeris) was investigated in Pantanal de Poconé (Mato Grosso, Brazil). In 0.3, 8.6 and 8.0% of the horses, dogs and capybaras, respectively, infection was detected using standard parasitological methods. A seroprevalence of 4.1, 2.3, 7.1 and 22.0% was found in horses, cattle, dogs and capybaras, respectively, using an enzyme-linked immunosorbent assay for the detection of T.evansi antigen ...
Comparison of daily and monthly pyrantel treatment in yearling thoroughbreds and the protective effect of strategic medication of mares on their foals. Studies on a Thoroughbred breeding farm in Ohio were done to: (1) compare the effects of daily administration of pyrantel tartrate feed pellets with monthly administration of a pyrantel pamoate paste to yearling horses (21 January-3 September); (2) assess the effects of daily pyrantel tartrate given strategically in spring/summer to foaling mares (1 April-16 August) and given for a prolonged period to barren mares (21 January-3 September); (3) determine if strategic medication of foaling mares with daily pyrantel tartrate protected their foals until weaning. There were no differences in cyatho...
[Tapeworms, a problem in equine practice?]. This paper gives a survey on biology and ecology of equine tapeworms as well as on pathogenesis, clinics, diagnosis, therapy, and prophylaxis of tapeworm infections.
Survey in central Kentucky for prevalence of Anoplocephala perfoliata in horses at necropsy in 1992. A total of 118 horses was examined at necropsy in central Kentucky for the tapeworm Anoplocephala perfoliata. The examination period was between 28 August and 21 December 1992. Prevalence was 64% for Thoroughbreds (n = 81 examined) and 54% for non-Thoroughbreds (n = 37 examined). The number of tapeworms per infected horse varied from one to 853. Data on infections are categorized by breed, sex (n = 38 males, 8 geldings, and 72 females), age (1-31 years), and month of necropsy of the horses.
A comparison between the effects of conventional and selective antiparasitic treatments on nematode parasites of horses from two management schemes. Little information exists concerning the presence of nematode parasites of horses in South Africa. Limited studies are available which compare the parasites in horses originating from differing management schemes. The aim of the present study was to compare the nematode parasites of 2 groups of horses which had been managed differently. Group 1, chiefly Nooitgedacht adult ponies, consisted of cycling or early pregnancy mares. They were maintained chiefly on zero grazing, given supplemental feed and treated 4 times a year with antiparasitic remedies. The horses in Group 2 were mostly Thoroughbr...
Hyperlipemia in 9 miniature horses and miniature donkeys. The medical records from 9 consecutive miniature horses (n = 5) and miniature donkeys (n = 4) with hyperlipemia (serum triglyceride concentration > 500 mg/dL) were reviewed. In all cases, hyperlipemia was a secondary complication of a primary systemic disease including septicemia, colitis, parasitism, esophageal obstruction, gastric impaction and rupture, fecalith, and pituitary adenoma. Therapy consisted of specific treatment for the primary disease, supportive care, and nutritional support. The mean time for resolution of hyperlipemia in cases requiring nutritional support (n = 6) was 7 days...
[Eimeria leuckarti infections in foals and their mothers in upper Bavaria]. In this epidemiological study 30 mares and their foals from seven farms in Upper Bavaria were investigated. Eimeria-leuckarti-oocysts were found in 24 foals (80%), but only in one mare. Oocysts were first detected 28 days post partum at the earliest and 191 days post partum at the latest. In foals, excretion of oocysts usually occurred intermittently with coproscopically negative intervals of up to 15 weeks, and was most frequent in June (8 foals), July (17 foals), and August (10 foals). With the exception of two animals which had mild diarrhoea, the oocyst-shedding foals showed no clinical si...
Comparative genetic analysis of Swiss and Spanish isolates of Echinococcus granulosus by southern hybridization and Random Amplified Polymorphic DNA technique. Swiss and Spanish isolates of Echinococcus granulosus were compared using different molecular biological techniques: Genomic DNAs isolated from parasites originating from various intermediate hosts were subjected to Southern hybridization with different probes, the same source of DNA was used for DNA amplification using the Random Amplified Polymorphic DNA (RAPD) technique. With both methods the various isolates (metacestodes) of E. granulosus exhibited characteristic banding patterns which allowed us to assign them to the following groups of homologous profiles: (a) isolates of horse and donk...
Incidence of Anoplocephala perfoliata in horses examined at an Irish abattoir. The intestinal tracts of 363 horses were examined after slaughter at a horse abattoir. The presence or absence of Anoplocephala perfoliata and the sites of attachment were recorded. A total of 51 per cent of the horses had A perfoliata attached to the mucosa of the ileocaecal junction and/or to the caecal mucosa; 5 per cent of the horses had A perfoliata attached only to the mucosa of the ileocaecal junction, 24 per cent had A perfoliata attached only to the caecal mucosa and 22 per cent of the horses had A perfoliata attached at both sites. The degree of infestation did not appear to be influ...
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 musc...
Diagnosis of Babesia caballi infections in horses by enzyme-linked immunosorbent assay (ELISA) and western blot. From Babesia caballi in vitro cultures a preparation of 100% infected erythrocytes was obtained. From this, B. caballi antigens were extracted with the detergent 3-[(3-Cholamidopropyl)-dimethylammonio]-1-propane-sulfonate (CHAPS) and used as ELISA antigens. A control antigen of normal erythrocytes from the same donor horse was prepared in an identical manner. The ELISA and Western blot were validated by testing of sera from horses experimentally infected with B. caballi or B. equi or not infected with Babesia spp. ELISA and Western blot results were compared with those obtained by the immunofl...
[An evaluation of the direct agglutination test for the diagnosis of “mal de caderas” in horses]. The usefulness of the direct agglutination test (DA) to diagnose Mal de Caderas disease was evaluated. Forty four sera samples from two lots of horses with natural T. evansi infection (Lot 1 and Lot 2) were used. Thirteen (81.2%) of sixteen horses in which parasites were isolated gave positive agglutination titres (> or = 1:512) in the DA test. Treatment of these positive sera with 2-mercaptoethanol drops three to eight dilutions the agglutination titres in twelve samples (92%), showing the IgM nature of these antibodies. The DA test was also positive in seventeen of twenty eight horses in ...
Specific immune responses are required to control parasitemia in Babesia equi infection. Horses possessing a normal immune system and spleen often control infection caused by Babesia equi. However, splenectomized horses are unable to control B. equi infection and usually succumb to the infection. To investigate the role of the spleen in the control of B. equi infection in the absence of specific immune responses, two 1-month-old foals with severe combined immunodeficiency (SCID) and two age-matched normal foals were inoculated with B. equi. The SCID foals became febrile seven days postinoculation and developed terminal parasitemias of 41 and 29%. The SCID foals had greater than 50...
Drug therapy in the neonatal foal. The neonatal period in foals refers to the first 7 days of postnatal life. The effects of drugs (pharmacologic agents) may be different in neonatal foals, particularly during the first 3 days of postnatal life, from those in older foals and adult horses. The changed drug effects decrease as the physiologic processes that affect absorption, distribution, and elimination (metabolism and excretion) of drugs mature. Dosage regimens should take into account the altered pharmacokinetic profiles of drugs, and because of wide individual variation, the response to therapy should be closely monitored fo...
Transmission of some species of internal parasites in horses born in 1990, 1991, and 1992 in the same pasture on a farm in central Kentucky. Studies were conducted on transmission of natural infections of several species of internal parasites in horses born and kept on the same pasture on a farm in central Kentucky. Data for the first year (1989) of a 4 year study on this farm have been published recently. The present research represents the second (1990), third (1991), and fourth (1992) years of the investigation. The number of animals (n = 28) examined varied from eight born in 1990 to ten each born in 1991 and 1992. For each year, examination was made of one horse per month, beginning in June of the year of birth and extending t...
