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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.
Prevalence of Setaria equina microfilaraemia in horses in Hungary. Peripheral blood samples were collected randomly from 195 horses in various parts of Hungary, and the presence of microfilariae was evaluated by the Knott technique. On the basis of morphological identification 18 of the horses (9.2 per cent) were infected with Setaria equina, and the infection was confirmed in 10 animals by pcr and sequencing. The level of microfilaraemia was between 1 and 1138 larvae in 2 ml of blood. There was no correlation between the time of sampling or the sex of the animals (stallions versus mares) and the prevalence of infection, but the prevalence decreased with age....
Interpretation of serum antibody response to Anoplocephala perfoliata in relation to parasite burden and faecal egg count. Increased knowledge is needed to assist in the interpretation of presently available diagnostic techniques for infection by the tapeworm Anoplocephala perfoliata in horses. Objective: The suggested cut-off level of an A. perfoliata specific ELISA may not adequately reflect the actual infection level. Hence, faecal egg counts may be a more useful diagnostic test for individual horses than previously reported. Methods: Eighty-four horses admitted for slaughter at a Danish abattoir were examined for the presence of A. perfoliata. The number of tapeworms, their stage of development and gross patho...
Diagnostic real-time PCR assay for the quantitative detection of Theileria equi from equine blood samples. We developed a TaqMan real-time polymerase chain reaction (PCR) assay for the quantitative detection of Theileria equi from the in vitro-cultured parasite and field blood samples collected from horses living in Ghana and Brazil. The detection limit for the assay was determined to be 1.5 parasites/microl per sample, and the quantitative capacity was demonstrated using the in vitro-cultured parasite. For field applications, the real-time PCR assay was compared to a previously established nested PCR assay used as the gold standard for the real-time PCR assay. Of 65 field blood samples, 46 samples...
Histomonas meleagridis (Parabasala, Trichomonadea, Monocercomonadidae): presence of natural agglutinins in horse serum. Cultured Histomonas meleagridis cells were readily agglutinated in vitro by horse serum at concentrations as low as 5%, although clumping was more rapid and prominent at 15% or higher. For observation of clumping, the cultured organisms were washed twice in Hanks balanced solution (HBSS) by centrifugation (1,000 x g for 15 min) and filtered through glass wool. The test sera were added and the mixture incubated in a Petri plate or 24-well culture plates at r.t. for 15-30 min. Formation of clumps was time- and concentration-dependent. Gentle agitation hindered agglutination at low serum concentr...
Parascaris equorum in foals and in their environment on a Swedish stud farm, with notes on treatment failure of ivermectin. Environmental contamination and the egg excretion pattern of the ascarid Parascaris equorum (Nematoda) was investigated in relation to anthelmintic treatment on a Swedish stud farm. Faecal samples from 15 foals, dewormed every 8th-week with a paste formulation of ivermectin at the standard dose rate of 0.2 mg/kg bodyweight, were collected at five sampling occasions between August and November 2006. In addition, soil samples were obtained from four paddocks used by these foals in November 2006. The number of eggs per gram (epg) was counted in both faeces and soil. Egg excretion started when the...
The use of age-clustered pooled faecal samples for monitoring worm control in horses. A study was performed on two horse farms to evaluate the use of age-clustered pooled faecal samples for monitoring worm control in horses. In total 109 horses, 57 on farm A and 52 on farm B, were monitored at weekly intervals between 6 and 14 weeks after ivermectin treatment. This was performed through pooled faecal samples of pools of up to 10 horses of the groups 'yearlings' (both farms), '2-year-old' (two pools in farm A), '3-year-old' (farm A) and adult horses (four pools on farm A and five pools on farm B), which were compared with the mean individual faecal egg counts of the same pools. ...
Trypanosoma evansi: molecular homogeneity as inferred by phenetical analysis of ribosomal internal transcribed spacers DNA of an eclectic parasite. The protozoan Trypanosoma evansi is described as presenting high morphological and genetic similarities among the isolates despite its biological heterogeneity and wide geographical distribution. PCR amplification of the internal transcribed spacers of the ribosomal gene in combination with the coding region of the 5.8S ribosomal subunit further submitted to restriction enzymes digestion were carried out in DNAs extracted from 41 T. evansi strains isolated from horses, dogs, coatis and capybaras from two distinct regions of the Brazilian Pantanal. We also used one T. evansi isolate from Africa...
Incidence of myiasis in Panama during the eradication of Cochliomyia hominivorax (Coquerel 1858, Diptera: Calliphoridae) (2002-2005). We present the results of a study on myiasis in Panama during the first years of a Cochliomyia hominivorax eradication program (1998-2005), with the aim of investigating the behavior of the flies that produce myiasis in animals and human beings. The hosts that registered positive for myiasis were cattle (46.4%), dogs (15.3%), humans (14.7%), birds (12%), pigs (6%), horses (4%), and sheep (1%). Six fly species caused myiasis: Dermatobia hominis (58%), Phaenicia spp. (20%), Cochliomyia macellaria (19%), Chrysomya rufifacies (0.4%), and maggots of unidentified species belonging to the Sarcophagid...
Suspension of bone marrow-derived undifferentiated mesenchymal stromal cells for repair of superficial digital flexor tendon in race horses. It has been proven that mesenchymal stromal cells (MSCs) can differentiate into tenocytes. Attempts to repair tendon lesions have been performed, mainly using scaffold carriers in experimental settings. In this article, we describe the clinical use of undifferentiated MSCs in racehorses. Significant clinical recovery was achieved in 9 of 11 horses evaluated using ultrasound analysis and their ability to return to racing. Our results show that the suspension of a small number of undifferentiated MSCs may be sufficient to repair damaged tendons without the use of scaffold support. Ultrasound sca...
Molecular diagnosis of equid summer sores. Equine cutaneous habronemosis, also known as "summer sores", is a parasitic infection caused by larvae of Habronema microstoma and Habronema muscae (Nematoda, Spirurida) released by dung-inhabiting fly vectors on abraded skin, skin wounds or muco-cutaneous transition sites. Larvae induce a local inflammatory reaction characterised by itching, granulomatous, ulcerated and, often non-healing, lesions. The diagnosis of summer sores may be unreliable mainly because of the limits of clinical and microscopic examination. The applicability of a semi-nested PCR assay developed for the diagnosis of gas...
Parasite control practices on Swedish horse farms. Virtually all horses are infected with helminth parasites. For some decades, the control of parasites of Swedish horses has been based on routine treatments with anthelmintics, often several times per year. Since anthelmintic resistance is becoming an increasing problem it is essential to develop more sustainable control strategies, which are adapted to different types of horse management. The aim of this study was to obtain information on practices used by Swedish horse owners for the control of endoparasites. Methods: A questionnaire with 26 questions about management practices and parasite ...
Comparative study of doramectin and fipronil in the treatment of equine chorioptic mange. In equids, chorioptic mange is a common dermatitis for which there are no licensed medications in the uk. Doramectin and fipronil are licensed for the control of ectoparasites in other species and were evaluated for the treatment of 17 cases of chorioptic mange in 13 equids. Equids were included if clinical findings were indicative of chorioptic mange, chorioptes mites were positively identified and concurrent disease that could affect response to disease was not evident. A random number table was used to allocate subjects to receive doramectin (group D, eight animals) or fipronil (group F, ni...
Detection and molecular characterization of Babesia caballi and Theileria equi isolates from endemic areas of Brazil. Blood samples were collected from 487 adult horses, including 83 pregnant mares, at a slaughterhouse located in Araguari, Minas Gerais State, Brazil. For each blood sample, the packed cell volume (PCV) was determined, and Giemsa-stained smears were microscopically examined for the presence of hemoparasites. The plasma was examined by the indirect fluorescent antibody test for detection of antibodies against Babesia caballi and Theileria equi. In addition, DNA was extracted and analyzed by a multiplex real-time polymerase chain reaction (PCR), specific for B. caballi and T. equi. Products of PC...
Phylogeny of trichostome ciliates (Ciliophora, Litostomatea) endosymbiotic in the Yakut horse (Equus caballus). Ciliates of the subclass Trichostomatia inhabit the fermentative regions of the digestive tract of herbivores. Most available small subunit ribosomal RNA (SSrRNA) gene sequences of trichostomes are from species isolated from the rumen of cattle or sheep and from marsupials. No ciliate species endosymbiotic in horses has yet been analyzed. We have sequenced the SSrRNA genes of five ciliate species, isolated from the cecum and colon of four Yakut horses: Cycloposthium edentatum, Cycloposthium ishikawai, Tripalmaria dogieli, Cochliatoxum periachtum, and Paraisotricha colpoidea. Based on their mor...
Occurrence of anthelmintic resistant equine cyathostome populations in central and southern Italy. In the present survey, 276 horses bred on 16 farms located in central and southern Italy were investigated for the presence of drug resistant cyathostomes by a Fecal Egg Count Reduction Test (FECRT). Sixteen to 20 animals were selected on each farm and randomly assigned to one of four equally sized treatment groups. Groups were treated with fenbendazole, pyrantel pamoate, ivermectin or moxidectin. Resistance to fenbendazole was declared on six farms (37.5%) and suspected in two farms (12.5%), with FECR values ranging from 41% to 88.3%. Resistance to pyrantel was found in two farms (12.5%) and ...
Statistical approach to measure the efficacy of anthelmintic treatment on horse farms. Resistance to anthelmintics in gastrointestinal nematodes of livestock is a serious problem and appropriate methods are required to identify and quantify resistance. However, quantification and assessment of resistance depend on an accurate measure of treatment efficacy, and current methodologies fail to properly address the issue. The fecal egg count reduction test (FECRT) is the practical gold standard for measuring anthelmintic efficacy on farms, but these types of data are fraught with high variability that greatly impacts the accuracy of inference on efficacy. This paper develops a statis...
Accuracy of an indirect fluorescent-antibody test and of a complement-fixation test for the diagnosis of Babesia caballi in field samples from horses. We evaluated the indirect fluorescent-antibody (IFA) test and complement-fixation (CF) test for diagnosis of equine piroplasmosis in the absence of a gold standard. Using Evan's blue, we estimated the specificity of the IFA test on a parasite-free, field horse population to be 98% (95% confidence interval=97, 99). We observed an excellent test agreement (kappa=0.83) between two collaborating laboratories when the IFA test was performed on identical samples from an endemic area. Using Bayesian analysis with informative prior probability distributions, we estimated the sensitivity of the IFA tes...
Detection and semi-quantification of Strongylus vulgaris DNA in equine faeces by real-time quantitative PCR. Strongylus vulgaris is an important strongyle nematode with high pathogenic potential infecting horses world-wide. Several decades of intensive anthelmintic use has virtually eliminated clinical disease caused by S. vulgaris, but has also caused high levels of anthelmintic resistance in equine small strongyle (cyathostomin) nematodes. Recommendations aimed at limiting the development of anthelmintic resistance by reducing treatment intensity raises a simultaneous demand for reliable and accurate diagnostic tools for detecting important parasitic pathogens. Presently, the only means available t...
Treatment of natural infestations of the biting louse (Werneckiella equi) on horses using triflumuron, a benzoylurea derivative insect growth regulator. The horse biting louse (Werneckiella equi) is a common global equine ectoparasite. To our knowledge, benzoyl(phenyl)urea insecticides (triflumuron, diflubenzuron) commonly used as sheep lousicides, have not been evaluated for efficacy against W. equi. The aim of this study was to determine louse control efficacy, general wellness and dermal safety following triflumuron application as a backline pour-on to horses. Two efficacy trials using 25 adult naturally infested lousy horses, and a dermal safety trial using 10 adult louse-free horses were conducted over a 14-month period. Lousy animals wer...
Correlation between colic and antibody levels against Anoplocephala perfoliata in horses in The Netherlands. The importance of Anoplocephala perfoliata in horses with colic was studied in 139 horses referred for colic and 139 control horses with no signs of colic for at least three years. The serodiagnostic method of Proudman and Trees, which measures the level of A. perfoliata antibody, was used to detect A. perfoliata infection. Thirty-two horses were examined at necropsy, to determine whether the presence of A. perfoliata in the ileocaecal region was associated with the A. perfoliata antibody level. The mean A. perfoliata antibody level was significantly higher in horses with colic than in horses ...
Validation of the indirect fluorescent antibody and the complement fixation tests for the diagnosis of Theileria equi. The indirect fluorescent antibody (IFA) test for Theileria equi was evaluated to assess test's suitability for the serological diagnosis of equine piroplasmosis, to provide performance parameters for the purpose of test validation, and to compare it with the complement fixation (CF) test. Using a protocol that included Evan's blue, the specificity of the IFA test was estimated at 99.0% for T. equi by the classical method of analysis, and 96.6% by the Bayesian method. The use of Evan's blue in the test protocol increased test specificity and contributed to an excellent test agreement between tw...
Evidence-based parasitology in horses. This article focuses on what has been established concerning the interaction of equine parasites and their hosts, highlighting those issues for which convincing data are still lacking. There is a compelling need for the participation of the veterinarian in the design of appropriate anthelmintic treatments and prevention strategies.
Establishment of a panel of reference Trypanosoma evansi and Trypanosoma equiperdum strains for drug screening. The animal pathogenic protozoan, Trypanosoma evansi, leads to a wasting disease in equines, cattle and camels, commonly known as Surra. It is extensively distributed geographically with a wide range of mammalian hosts and causes great economical loss. Trypanosoma equiperdum causes a venereal disease called Dourine in horses and donkeys. Chemotherapy appears to be the most effective form of control for T. evansi, whereas infections caused by T. equiperdum are considered incurable. Due to emerging drug resistance, efficient control of T. evansi is severely threatened, emphasising the urgent need...
The comparative morphology of three equine habronematid nematodes: SEM observations. Drashia megastoma Rudolphi, 1819, Habronema muscae Carter, 1861 and Habronema microstoma Schneider, 1866 are found in the stomach of equine definitive hosts and are known to cause pathogenic effects in the stomach wall, skin, eye and occasionally other sites. These nematodes utilise either house flies or stable flies as their intermediate hosts. Apart from molecular findings that have demonstrated some of the differences between H. muscae and H. microstoma, no detailed morphological description of equine habronematid nematodes has been presented. This article describes most surface features of...
Molecular evidence for transplacental transmission of Theileria equi from carrier mares to their apparently healthy foals. The intra-erythrocytic parasite Theileria equi is one of two tick-transmitted causative agents of equine piroplasmosis. Piroplasms of T. equi can be transmitted across the equine placenta and once a horse is infected, it appears to remain a lifelong carrier, since anti-theilerial drugs suppress but do not eliminate the parasite. Carrier mares may transmit the organism to their offspring and this may result in abortion or neonatal piroplasmosis, but observations by some researchers suggest that foals may be born as carriers yet remain apparently healthy. Using a T. equi-specific oligonucleotide...
[Detection of Babesia caballi (Nuttall, 1910) and Theileria equi (Syn. Babesia equi , Laveran, 1901) by the polymerase chain reaction (PCR) in show and sport horses in the region of Ankara]. The aim of this study was to compare the diagnosis of Babesia caballi and Theileria equi by the polymerase chain reaction (PCR) and microscopic examination of blood specimens collected from show and sport horses in the region of Ankara in 2004. The blood specimens were collected from randomly selected 200 show and sport horses in the region of Ankara during the tick season as well as before and after the tick season for PCR testing. At the same time, Giemsa stained peripheral blood smears were examined for the presence of Babesia spp. and also the horses were examined for the presence of ticks...
Pathomorphological study on gastroduodenal ulceration in horses: localisation of lesions. Gastroduodenal ulceration is a prevalent disease in foals and adult horses. Decreased performance as well as fatal complications relate to this syndrome. The objective of our study was to determine the prevalence of gastric ulceration in a mixed population of horses by postmortem examination and to evaluate a possible association between equine gastric ulcer syndrome (EGUS) and sex or age of the examined horses, to evaluate the localisation of lesions in the proximal part of the gastrointestinal tract and to determine the occurrence of gastric parasites. Postmortem examinations were performed ...
