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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.
In vitro isolation of equine piroplasms derived from Cape Mountain zebra (Equus zebra zebra) in South Africa. Twenty blood samples of zebras (Equus zebra zebra) from the Karoo National Park and the Bontebok National Park in South Africa, all seropositive for Theileria equi, were subjected to in vitro culture to identify carrier animals and to isolate the parasites. Sixteen animals had a detectable parasitaemia in Giemsa-stained blood smears examined before culture initiation, the remaining four animals were identified as T. equi carriers by in vitro culture. Cultures were initiated either in an oxygen-reduced gas mixture or in a 5% CO2-in-air atmosphere. Out of the 20 blood samples, 12 cultures of T. ...
Comparative use of faecal egg count reduction test, egg hatch assay and beta-tubulin codon 200 genotyping in small strongyles (cyathostominae) before and after benzimidazole treatment. A survey on benzimidazole (BZ) resistance in small strongyles was performed on three farms in the tenth region in Chile. Samples from a total of 100 horses were tested using the faecal egg count reduction test (FECRT), the egg hatch assay (EHA) and an allele-specific PCR for the detection of beta-tubulin isotype 1 genes coding for phenylalanine (phe) or tyrosine (tyr) at codon 200. In the past, BZ-type drugs have been used within anthelmintic campaigns on all the three farms. This has predictably led to a high degree of BZ resistance at the Valdivia and Riñihue farms and to a lesser degree at...
Detection of equine Babesia spp. gene fragments in Dermacentor nuttalli Olenev 1929 infesting mongolian horses, and their amplification in egg and larval progenies. Babesia equi (EMA-1) and Babesia caballi (BC48) gene fragments were amplified by polymerase chain reaction (PCR), in blood samples, and partially fed-females and egg and larval progenies of Dermacentor nuttalli, collected from horses in Altanbulag, Tuv Province, Mongolia. While Babesia parasite DNA was detected in some horse blood samples during the first PCR, all positive cases in partially fed-female ticks, eggs and larvae were confirmed by nested PCR. Present study reinforces earlier similar findings in unfed D. nuttalli ticks collected from an open space vegetation in Bayanonjuul, Tuv Prov...
The potential reservoir role of donkeys and horses in zoonotic fascioliasis in Gharbia Governorate, Egypt. No doubt, fascioliasis tops all the zoonotic helminthes worldwide. In Egypt, human fascioliasis is increasing. The incidence and prevalence of fascioliasis in the Egyptian farm animals are well documented. However, none in Egypt has focused on the potential role of other domestic farm animals. A preliminary coprologic examination of donkeys and horses was done in eight centers of Gharbia governorate. The overall rate of infection in donkeys was 3.03%, in horses was 1.5%, and in mules 0.0%. Horses 2/74 (2.70%) and 1/26 (3.86%) were infected in Zefta and El Mahala El Kobra centers respectively. ...
Evaluation of ELISA and Western Blot Analysis using three antigens to detect anti-Trichinella IgG in horses. We assessed a serological method for detecting Trichinella infection in horses, specifically, an ELISA using three antigens to detect anti-Trichinella IgG (i.e. a synthetic tyvelose glycan-BSA (stg-BSA) antigen, an excretory/secretory (ES) antigen, and a crude worm extract (CWE) antigen). Serum samples were collected from 2502 horses (433 live horses from Romania and 2069 horses slaughtered in Italy and originating from Italy, Poland, Romania, and Serbia). Serum samples were also taken from horses experimentally infected with different doses of T. spiralis and T. murrelli larvae, as controls. ...
Sustainable use of anthelmintics in grazing animals. It is suggested that the major factor in avoiding the development of anthelmintic resistance is the percentage of worms that do not encounter the anthelmintics (worms in refugia). This in turn is determined by the numbers of larvae on pasture, the percentage of animals treated and whether any stages in the host can avoid the action of anthelmintic. To maintain anthelmintic efficacy the percentage of worms in refugia must be sufficiently large. In cattle, this should involve treating only first-year animals and using a different pasture each year for calves. For sheep, only animals that have to...
Gynandromorphism in Amblyomma cajennense and Rhipicephalus sanguineus (Acari: Ixodidae). During a survey of ticks on horses in November 2000, at the University of São Paulo farm in Pirassununga county, São Paulo, Brazil, 1 gynandromorph of Amblyomma cajennense was collected from a naturally infested horse. In another survey on dogs in March 2001, in the urban area of Monte Negro, Rondônia, Brazil, a gynandromorph of Rhipicephalus sanguineus was collected from a naturally infested dog. Both specimens are described and classified as perfect bipartite protogynanders.
One season of pasture exposure fails to induce a protective resistance to cyathostomes but increases numbers of hypobiotic third-stage larvae. The development of acquired resistance to cyathostome challenge after 1 season's exposure to a cyathostome-contaminated pasture was investigated using 17 parasite-naive ponies, which were 2-3 yr of age. These were divided into 3 groups: 1 to graze a cyathostome-contaminated pasture for 4 mo (exposed ponies), 1 to graze a "clean" pasture not previously grazed by parasitized animals (nonexposed ponies), and 1 group to remain in the barn under helminth-free conditions (parasite-free ponies). After pasture exposure all ponies were housed in stalls in the barn dewormed with ivermectin (200 microgra...
Risk factors for high endoparasitic burden and the efficiency of a single anthelmintic treatment of Danish horses. A questionnaire survey regarding endoparasite control practices in Danish horse herds was carried out in 1995. The participating veterinarians and herd owners were sampled using convenience and purposive sampling. In the analysis of risk factors for development of a high endoparasitic burden (> 200 eggs per gram faeces) 903 horses were sampled and the analysis of the efficiency of a single anthelmintic treatment was based on 605 horses. The following factors had a significant effect on the endoparasitic burden: herd type, age of the horses, use of pasture rotation, anthelmintic treatment of ho...
Sarcocystis neurona: parasitemia in a severe combined immunodeficient (SCID) horse fed sporocysts. Sarcocystis neurona was isolated from the blood of a 5-month-old Arabian foal with severe combined immunodeficiency. The foal had been inoculated approximately 3 weeks previously with 5 x 10(5) sporocysts that were isolated from the intestines of an opossum and identified by restriction enzyme analysis of PCR products as S. neurona. The isolate obtained from the blood of this foal was characterized by genetic, serologic, and morphologic methods and identified as S. neurona (WSU1). This represents the first time that S. neurona has been isolated from any tissue after experimental infection of a...
Detection of natural infection of Boophilus microplus with Babesia equi and Babesia caballi in Brazilian horses using nested polymerase chain reaction. The potential role of Boophilus microplus as a natural tick vector of Babesia equi and Babesia caballi in Brazilian horses was assessed using nested polymerase chain reaction (PCR)-based marker assay. B. equi merozoite-specific 218bp gene fragment was detected in almost 96% of horse blood samples, and 45.3-62.5% of females, eggs, larvae, and nymphs of B. microplus collected from 47 horses at Campo Grande in the State of Matto Grosso, Brazil. Except for the partially-fed female ticks, the B. caballi-specific 430bp gene fragment was amplified from horse blood samples, and all developmental stage...
Recommended terminology and advances in the systematics of the Cyathostominea (Nematoda: Strongyloidea) of horses. Terminology for common names for the Tribe Cyathostominea (cyathostomins), and disease caused by the nematodes (cyathostominosis), were recommended to replace the previously used names cyathostomes and cyathostomosis, which are ambiguous, inaccurate or synonymous, by the Third Internal Workshop on the Systematics of Cyathostominea of Horses, held in Stresa, Italy, 28 August 2001. The progress by this international working group at three workshops is reviewed briefly and a list of publications is provided. Included are an annotated checklist by genus and species of 93 species level names and th...
Eimeria organisms develop in the epithelial cells of equine small intestine. Histopathologic and immunohistochemical examinations were performed to determine the origin of host cells parasitized by Eimeria in the small intestines collected from five foals. Eimeria organisms at various stages (mainly microgametes and macrogametes) were frequently found in the cytoplasm of hypertrophied host cells in the lamina propria at the tips of villi of the jejunum and ileum. The cytoplasm of the host cell was immunohistochemically positive for cytokeratin AE1/AE3 and cytokeratin 13 and was negative for vimentin, desmin, alpha-smooth muscle actin, chromogranin A, neuron-specific en...
Mast cell and eosinophil mucosal responses in the large intestine of horses naturally infected with cyathostomes. From December 1998 to March 2000, caecum and ascendant colon of 42 horses naturally infected with cyathostomes were collected during routine necropsy or from a local slaughterhouse. Changes in the numbers of mucosal and submucosal mast cells (MMC and SMMC), intraepithelial, mucosal and submucosal eosinophils (IE, ME and SME) in the large intestine were investigated by histochemical techniques in relation to the worm burdens. The effect of age was examined in three subgroups: 6-24-month-old horses (group 1), 2-10-year-old horses (group 2) and horses more than 10 years of age (group 3). No globu...
Invasion, and short- and long-term survival of Babesia divergens (Phylum Apicomplexa) cultures in non-bovine sera and erythrocytes. In order to explore the feasibility of producing a Babesia divergens live vaccine free of bovine material contaminants the parasite's ability to grow in human, sheep and horse erythrocytes and serum and serum-free medium was investigated. B. divergens was successfully maintained in bovine erythrocytes overlaid with serum-free HL-1 medium. Supplementation of the culture medium with bovine or sheep serum improved parasite growth (monitored by measuring parasitaemia and uptake of tritiated hypoxanthine) whereas horse and human sera reduced parasite growth. As assessed by Giemsa's stained and FITC...
An analysis of human pathogens found in horse/mule manure along the John Muir Trail in Kings Canyon and Sequoia and Yosemite National Parks. To determine the prevalence of microorganisms that are potentially pathogenic for humans in horse/mule manure along the John Muir Trail (JMT). Methods: Random samples of horse/mule manure were collected along sections of the JMT in Yosemite, Kings Canyon, and Sequoia national parks (NP), as well as in portions of the Pacific Crest Trail (PCT) and selected JMT/PCT access trails. Convenience samples of wild animal scat found within I mile of trails were also collected. The fresh specimens were individually preserved both in 0.9% saline and polyvinyl alcohol (PVA)-containing tubes and stored at 4...
Pharmacokinetics of doramectin and ivermectin after oral administration in horses. A study was undertaken in order to compare plasma disposition kinetic parameters of doramectin (DRM) and ivermectin (IVM) in horses after oral administration. Ten crossbreed adult horses, clinically healthy, weighing 380-470 kg body weight (bw) were selected for study. Faecal examinations were performed to determine faecal parasite egg counts. Horses were allocated to two groups of five animals to provide an even distribution considering the variables sex, body weight and faecal egg count. Group I, were treated with an oral paste formulation of IVM at 0.2 mg/kg b/w and Group II, were treated w...
Evaluation of tests for anthelmintic resistance in cyathostomes. Resistance, especially to the anthelmintic benzimidazoles (BZ), has been reported in horse cyathostomes world-wide. Diagnosis of resistance has traditionally been made by faecal egg count reduction (FECR) trials, however, this technique has limitations. Some of the shortcomings may be resolved by refining the test or by using an in vitro test. FECR tests and the larval development assay (LDA) were performed on adult horses held on 15 different horse properties across a wide geographical area of NSW, Australia. FECR were measured before and 10-14 after days treatment with oxibendazole (OBZ), mo...
Seroprevalence of Neospora, Toxoplasma gondii and Sarcocystis neurona antibodies in horses from Jeju island, South Korea. Parasite-specific antibody responses to Neospora spp. and Toxoplasma gondii, antigens were detected using the indirect fluorescent antibody test (IFAT) and immunoblot analysis in a korean equine population located on Jeju island, South Korea (126 degrees 12' E and 33 degrees 34' N). For comparison, a naturally infected Neospora hughesi horse and an experimentally inoculated T. gondii equid (pony) were used. In addition, all samples were tested for antibodies to Sarcocystis neurona by immunoblot analysis. A total of 191 serum samples from clinically normal horses were evaluated. Only 2% (4 out ...
Antigen-specific IgG(T) responses in natural and experimental cyathostominae infection in horses. Equine clinical larval cyathostominosis is caused by simultaneous mass emergence of previously inhibited larvae from the mucosa of the colon. Clinical signs include diarrhoea, colic, weight loss and malaise, and in up to 50% of cases, the disease results in death. Cyathostominae spend a large part of their life cycle as larval stages in the intestinal mucosa. Definitive diagnosis is difficult due to the lack of diagnostic methods for pre-patent infection. In the present study, the enzyme-linked immunosorbent assay (ELISA) was used to investigate isotype responses to larval cyathostominae somat...
Culture, isolation and propagation of Babesia caballi from naturally infected horses. Thirteen blood samples of horses from South Africa, five of which were seropositive for Babesia caballi and eight for both B. caballi and Theileria equi, were subjected to in vitro culture to identify carrier animals. None of the animals had a detectable parasitaemia on Giemsa-stained blood smears before culture initiation. Cultures were initiated in L-cysteine-enriched medium, either in an oxygen-reduced gas mixture or in a 5% CO2-in-air atmosphere. All five animals seropositive for B. caballi were identified as carrier animals using an oxygen-reduced atmosphere, whereas only four samples bec...
Ultrastructural aspects of the oesophageal and reproductive systems of the equine parasite Strongylus vulgaris. The ultrastructure of the dorsal oesophageal gland ampulla and its relationship with the oesophagus, oesophageal ultrastructure, and control mechanisms in oesophageal activity were studied. Terminal ducts of the sub-ventral glands open through the oesophageal crown at the base of the buccal cavity. The terminal duct of the dorsal oesophageal gland running through the dorsal gutter opens to the exterior at the rim 'groove' of the buccal capsule. The posterior oesophageal region is clavate and the cuticle of the lumen folds to form outlet valves, 'valvulae'. An inconspicuous oesophago-intestinal...
Helminth control used by trainers of thoroughbreds in England. A telephone survey was conducted of the methods used to control parasitic worms at 106 thoroughbred training yards. Most of the horses were allowed access to grass and were therefore at risk of infection. The control methods relied primarily on the use of anthelmintics and appeared reasonably successful because only 44 per cent of trainers reported observing clinical signs of nematode infections. They dosed their horses frequently, 40 per cent treating every four to six weeks and 25 per cent treating every seven to eight weeks. New arrivals on yards were usually treated with anthelmintic but t...
Some morphological aspects of Cylicocyclus brevicapsulatus (Nematoda: Cyathostominae) parasite of horse. This paper describes some morphological aspects of Cylicocyclus brevicapsulatus (Ihle, 1920) (Nematoda: Cyathostominae) from Equus caballus in Brazil. The worms were studied using an optical microscope (measurements and illustrations) and a scanning electron microscope for a more detailed examination of the external morphology. The buccal capsule is very short, with a very thin wall, and the dorsal gutter is absent. Other morphological aspects are described including measurement of the spicules and gubernaculum.
Reduced levels of nitric oxide metabolites in cerebrospinal fluid are associated with equine protozoal myeloencephalitis. Equine protozoal myeloencephalitis (EPM) is a disease of horses that is primarily associated with infection with the apicomplexan Sarcocystis neurona. Infection with this parasite alone is not sufficient to induce the disease, and the mechanism of neuropathogenesis associated with EPM has not been reported. Nitric oxide (NO) functions as a neurotransmitter, a vasodilator, and an immune effector and is produced in response to several parasitic protozoa. The purpose of this work was to determine if the concentration of NO metabolites (NO(x)(-)) in the cerebrospinal fluid (CSF) is correlated with...
Echinococcus granulosus: regulation of leukocyte growth by living protoscoleces from horses, sheep, and cattle. To determine whether living hydatid tissue can, like hydatid fluid, regulate leukocyte growth, T-cell, B-cell, and macrophage lines were cocultured with protoscoleces of Echinococcus granulosus and their growth was compared with that of control cultures by thymidine uptake estimates and chemiluminescent assays of cell number. Protoscoleces supported mitosis of IL-1-deprived D10 T cells, but did not increase D10 count. The action of protoscoleces was affected by the species and organ of their origin and the length of time in culture. Unusually marked mitotic reaction, unaffected by parasite age...
