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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.
[The efficacy of anthelmintic drugs against horse strongyles in the area of Salzburg and preliminary results of selective anthelmintic treatment]. In recent years more and more cases of anthelmintic resistant equine strongyles were reported. The latest developments are cases of resistance against macrocyclic lactones. In order to delay this process less anthelmintics and only those which have been previously tested for their efficacy on each individual farm should be used. During the grazing season 2008 faecal samples of 281 horses and 5 donkeys from 26 farms were analysed in the area of Salzburg. To 164 of these horses selective anthelmintic treatment was implemented. Every four weeks faecal samples from the 164 horses were quantitative...
Field tests demonstrating reduced activity of ivermectin and moxidectin against small strongyles in horses on 14 farms in Central Kentucky in 2007-2009. Efficacy of ivermectin (IVM) and moxidectin (MOX) against small strongyles was evaluated in horses (n=363) in field tests on 14 farms in Central Kentucky between 2007 and 2009. Most of the horses were yearlings but a few were weanlings and mares. The number of horses treated with IVM was 255 and those treated with MOX was 108. Horses on six farms were allotted into two groups. One group was treated with each of the two drugs, whereas horses on the other eight farms were treated with only one of the two drugs--IVM on six farms and MOX on two farms. Strongyle eggs per gram of feces (EPGs) compar...
Horse infection with intestinal helminths in relation to age, sex, access to grass and farm system. A 11-year survey on helminth intestinal infection of horses was done in seven provinces of southern Poland. 21,641 faecal samples were collected from horses of different age, sex, breed and management system originating from 84 farms. Age was the major factor influencing the cyathostome egg excretion, the maximum being observed in yearlings and second year horses. Parascaris was found mostly in foals and yearlings. The main factor for Anoplocephala was the access to pasture. The level of cyathostome egg shedding (EPG) could be related to sex (geldings had higher values of EPG), breed (Thorough...
Large intestinal mast cell count and proteinase expression is associated with larval burden in cyathostomin-infected horses. Cyathostomins are the principal pathogenic nematode of equidae worldwide. In other species mast cell (MC) proteinases, in particular chymases, appear to have protective roles. Knowledge of the equine intestinal immune response to cyathostomins is limited. Objective: To investigate MC numbers and proteinase expression in equine cyathostomin-infected large intestine. Objective: MC populations in the large intestine are positively associated with cyathostomin burden and predominantly express chymase. Methods: The caecal cyathostomin burden of naturally infected horses (n = 25) was determined by l...
Longitudinal study of an outbreak of Trypanosoma evansi infection in equids and dromedary camels in Israel. An outbreak of trypanosomoasis caused by Trypanosoma evansi involving horses, camels and donkeys occurred in a farm in Israel. A longitudinal study of two outbreak phases was conducted which included clinical monitoring, blood smears, packed cell volume (PCV), serology and polymerase chain reaction (PCR) followed by reverse dot blot (RDB) for the molecular detection of infection. This was the first reported T. evansi outbreak in domestic animals in Israel. Most of the camels on the farm (8/10; 80%) were diagnosed with T. evansi infection whereas infection was less prevalent in the horses (3/7;...
Host preferences of tabanid flies based on identification of blood meals by ELISA. Tabanid flies in Australia are potential vectors of the parasite Trypanosoma evansi which causes the animal disease surra. It is endemic to most of south-east Asia and could enter Australia, but evaluation of the potential impact of a surra incursion requires identification of the major hosts of Australian tabanids. This study investigated the natural pattern of feeding and host preference by tabanid flies of Townsville, north Queensland by identification of ingested blood in trap-caught tabanids using ELISA. The assays were developed for identification of horse, cow, macropod and pig blood me...
Pediculosis in two research ponies (Equus caballus). Horses and ponies are used infrequently in research but may be valuable animal models for studying both equine-specific diseases and biomedical applications. We report here 2 cases of pediculosis in random-source ponies. Infestation and clinical signs were not present during a 4-wk quarantine period or for 3 to 9 mo thereafter but became apparent coincident with the ponies' movement from pasture to indoor housing. These 2 geldings presented with pruritus associated with excoriating lesions on the neck, and infestation with Bovicola (Werneckiella) equi Denny, 1842 was diagnosed. Ponies were tre...
Studies of quinapyramine-resistance of Trypanosoma brucei evansi in China. In the present article, we summarize our studies of antrycide-resistance of Trypanosoma brucei evansi in four aspects in the last recent several years, the analysis of quinapyramine-sensitive situation of T. b. evansi in China, biological characteristics of T. b. evansi population in quinapyramine-resistance and biological materials of quinapyramine-resistance in T. b. evansi population. Firstly, the correlative assays of effective dosage of quinapyramine on T. b. evansi disease between in vivo and in vitro methods showed that their relationship was parabolic with positive correlation. On the ...
Prevalence of gastrointestinal parasites in working horses. Fecal samples for detection of gastrointestinal parasites were collected from 221 working horses from September 2002 to May 2003 from 14 villages in Urmia, North West of Iran. Fecal samples of 46 horses (20.8%) were negative for parasite eggs or oocysts. One hundred and seventy five positive horses (48.9%) were infected with a single parasite type and 49 (22.2%) and 18 (8.1%) of horses had multiple infections with two and three parasites, respectively. The highest prevalence and intensity rate belonged to small strongyles. The overall prevalence of intestinal parasites eggs and oocyst in the p...
Morphological and biochemical changes in the blood of horses naturally infected with Gasterophilus sp. larvae. Gasterophilus sp. constitute a group of specific parasites, which larval forms are found in horses and other phylogenetically related species--donkeys, mules and zebras. Their invasion is associated with marked fluctuations of hematological and biochemical blood parameters, including the activity of many enzymes and the electrolyte concentration. The purpose of the study was to analyze changes in selected biochemical and morphological blood parameters of horses infected with botfly larvae. The experimental group was formed of horses infested by Gasterophilus sp. larvae whereas the control grou...
In vitro selection and differentiation of ivermectin resistant cyathostomin larvae. Cyathostomins are considered to be the primary helminth pathogen of horses and macrocyclic lactones (ML) are the most frequently used anthelmintics. Therefore, ML resistance is a serious threat for the control of these parasites. In the present study ivermectin resistant cyathostomin L3 were in vitro selected, using a reiterative larval migration inhibition assay (rLMIA) and differentiated by reverse line blot (RLB). Larvae were obtained from two populations, one from a never treated, free-roaming horse population in the nature reserve Oostvaardersplassen (OVP) and the other from regularly ive...
Genetic diversity of piroplasms in plains zebra (Equus quagga burchellii) and Cape mountain zebra (Equus zebra zebra) in South Africa. Seventy EDTA blood samples collected from plains zebra (Equus quagga burchellii) and Cape mountain zebra (Equus zebra zebra) were screened for the presence of piroplasm parasite DNA using quantitative T. equi-specific and B. caballi-specific TaqMan real-time PCR (qPCR) tests. T. equi parasite DNA was detected in 60 samples, 19 of which were also positive for B. caballi. Approximately 1480bp of the piroplasm 18S rRNA gene was amplified and sequenced from 17 samples, while the V4 hypervariable region of the 18S rRNA gene was amplified, cloned and sequenced from 31 samples. BLASTN analysis reveal...
Nasal bots…a fascinating world! Larvae causing obligatory myiasis are numerous and they may affect cutaneous and subcutaneous tissues, wounds, nasopharyngeal cavities (nasal bots), internal organs and the digestive tract (bots) of domestic and wild animals and humans as well. Nasal bots belong to the Family Oestridae, Subfamily Oestrinae, which includes several important genera: Oestrus, Kirkioestrus, and Gedoelstia infecting Artiodactyla (except Cervidae) in Africa and Eurasia, Cephenemyia and Pharyngomyia infecting Cervidae, Rhinoestrus infecting horses, Cephalopina infecting camels, Pharyngobolus infecting African elephan...
Analysis of multiyear studies in horses in Kentucky to ascertain whether counts of eggs and larvae per gram of feces are reliable indicators of numbers of strongyles and ascarids present. Increasing levels of anthelmintic resistance in equine nematodes have led to recommendations of more sustainable anthelmintic treatment protocols with emphasis on parasite surveillance and diagnosis, rather than prophylactic calendar-based treatments. This requires knowledge of the diagnostic test performance of techniques for counts of eggs per gram of feces (EPG) as well as methods for culturing, counting and identifying third stage (L(3)) strongyle larvae per gram of feces (LPG). For horses, such information does not exist in the published literature. The aim of this study was to examine th...
Critical tests evaluating efficacy of moxidectin against small strongyles in horses from a herd for which reduced activity had been found in field tests in Central Kentucky. Critical tests were performed in 2009 and 2010 in four 2-year-old horses naturally infected with internal parasites. The horses were from a herd (Farm MC) where reduced activity of ivermectin and moxidectin on small strongyles was demonstrated previously from EPG (eggs/gram of feces) data in field tests. Also, in critical tests in horses from the same herd, ivermectin was less effective on immature small strongyles in the lumen of the large intestine than when the drug was first marketed. The main interest in the present critical tests was to determine the efficacy of moxidectin (400 μg/kg) o...
Morphology and diagnosis of the fourth-stage larva of Coronocyclus labratus (Looss, 1900) (Nematoda: Strongyloidea) parasitising equids. The fourth larval stage (L4) of Coronocyclus labratus (Looss, 1900) Hartwich, 1986, one of the common species of the Cyathostominae found in equids, is identified and described. The larvae found were identified as C. labratus by finding moulting forms possessing characters of both larval and adult stages. The larvae are similar to those of Cylicocyclus leptostomum (Kotlán, 1920) Foster, 1936, Cyathostomum catinatum Looss, 1900 and Cylicostephanus goldi (Boulenger, 1917) Lichtenfels, 1975. The buccal capsule (BC) wall of the L4 of Cylicocyclus leptostomum is thinner than that of Coronocyclus l...
Cutaneous and pulmonal habronemosis transmitted by Musca domestica in a stable in the United Arab Emirates. Nematode larvae found in histological cuts of lung tissue of a horse from a farm in Al Dhaid (UAE) were determined to belong to the Habronematidae family. The clinical examination of the other 18 horses present in the farm revealed summer sores (cutaneous habronemosis) in two stallions. Nematode larvae were found in 147 (=26.2%) out of 561 male but only in 64 (=8.7%) out of 739 female Musca domestica caught at the farm in November and December 2008. Conversely, all 15 Stomoxys calcitrans specimens caught in the farm resulted negative for nematode larvae. The housefly population caught in the b...
Shortened strongyle-type egg reappearance periods in naturally infected horses treated with moxidectin and failure of a larvicidal dose of fenbendazole to reduce fecal egg counts. Deworming horses with anthelmintics that have activity against encysted small strongyle larvae (L(3) and L(4)) is a common practice in parasite control programs. The two drugs currently available for this use are moxidectin (MOX) administered in a single dose of 0.4 mg/kg and fenbendazole (FBZ) given at the larvicidal dose (10mg/kg for 5 days). Here, we report the efficacy of MOX and the larvicidal dose of FBZ for reducing counts of strongyle-type eggs per gram of feces in naturally infected horses. Fecal egg counts (FECs) of 15 yearlings were observed following deworming. On day 0, 6 of the 1...
Practical aspects of equine parasite control: a review based upon a workshop discussion consensus. Development of resistance of several important equine parasites to most of the available anthelmintic drug classes has led to a reconsideration of parasite control strategies in many equine establishments. Routine prophylactic treatments based on simple calendar-based schemes are no longer reliable and veterinary equine clinicians are increasingly seeking advice and guidance on more sustainable approaches to equine parasite control. Most techniques for the detection of equine helminth parasites are based on faecal analysis and very few tests have been developed as diagnostic tests for resistan...
Surgical extraction of an intraocular infection of Parelaphostrongylus tenuis in a horse. A 4-year-old Hanoverian gelding was evaluated because of a mobile worm-like structure in the right eye. Results: Ophthalmologic examination of the right eye revealed a white, thin, coiled, mobile parasite, which was presumed to be a nematode, located in the ventral portion of the anterior chamber of the eye; there also were vitreal strands located temporally and inferiorly near the margin of the pupil. Results of ophthalmologic examination of the left eye were unremarkable. Results: The horse was treated with a neomycin-polymyxin B-dexamethasone ophthalmic solution applied topically (1 drop, q...
Antigenic characterization of Trypanosoma evansi using sera from experimentally and naturally infected bovines, equines, dogs, and coatis. The present research investigated the presence of T. evansi antibodies in animals from the subregion of Nhecolandia, in the Pantanal Sul-mato-grossense, by means of an enzyme linked immunosorbent assay (ELISA) and indirect immunofluorescence antibody test (IFAT), and the pattern of polypeptide recognition by sera from experimentally and naturally infected hosts using Western blotting. Serum samples were obtained from bovines (n = 102), horses (n = 98), and dogs (n = 55), and from 32 free-ranging coatis (Nasua nasua). None of the bovines were found positive, while sera from 16 dogs (29%) and 23...
Combined moxidectin and environmental therapy do not eliminate Chorioptes bovis infestation in heavily feathered horses. Chorioptes bovis infestation is a common cause of pastern dermatitis in the horse, with a predilection in draft horses and other horses with thick hair 'feathers' on the distal limbs. The treatment of this superficial mite is challenging; treatment failure and relapse are common. Furthermore, C. bovis infestation may affect the progression of chronic pastern dermatitis (also known as chronic proliferative pastern dermatitis, chronic progressive lymphoedema and dermatitis verrucosa) in draft horses, manifesting with oedema, lichenification and excessive skin folds that can progress to verruci...
Coprological prevalence and intensity of helminth infection in working horses in Lesotho. This study aimed to (1) estimate infection prevalence of strongyle, Oxyuris equi and Parascaris equorum species and the intensity of infection with strongyles in working horses in lowland Lesotho and (2) investigate associations between infection and horse age, sex and owner-reported use of anthelmintics. In a cross-sectional survey, fresh faecal samples were obtained from 305 randomly selected horses and worm egg counts performed using a validated field laboratory kit. Details of anthelmintic use were collected using a standardised face-to-face owner questionnaire. Infection prevalence estima...
Genetic diversity of equine piroplasms in Greece with a note on speciation within Theileria genotypes (T. equi and T. equi-like). Equine piroplasms in Greece were studied using the reverse line blot hybridization (RLB) assay. Three genotypes consisting of two Theileria (T. equi and T. equi-like) and one Babesia (B. caballi-like) were identified. Of 787 samples tested, 371 (47.14%) hybridised to catchall probe (probe specifically designed to capture any piroplasm species present in a sample), 346 (43.96%) to T. equi probe, 364 (46.25%) to T. equi-like probe, 0 (0%) to B. caballi probe and 3 (0.38%) to B. caballi-like probe. Seven samples gave faint signals with the catchall probe only, indicating the presence of known or ...
Neospora spp. and Toxoplasma gondii antibodies in horses in the Czech Republic. During January 2007, blood samples were collected from 552 healthy horses from nine different regions of the Czech Republic. Sera were tested for serum antibodies to Neospora caninum by a competitive-inhibition enzyme-linked immunosorbent assay and confirmed by an indirect fluorescent antibody test. The same samples were tested for serum antibodies against Toxoplasma gondii by a latex agglutination test. In total, 131 of 552 (24%) horses reacted positively for Neospora antibodies in competitive-inhibition enzyme-linked immunosorbent assay; seven of them had > or =50% of inhibition. Samples wer...
Comparative diagnosis of parasitological, serological, and molecular tests in dourine-suspected horses. Study on comparative sensitivity of parasitological, serological, and molecular tests on 237 horses originating from two dourine-suspected districts of Arsi-Bale highlands of Ethiopia was conducted to determine the prevalence of the disease and degree of agreement of the diagnostic tests. Accordingly, the prevalence of the disease was found to be 4.6%, 36.7%, and 47.6% by parasitological Woo test, RoTat 1.2 and 18S PCR tests, respectively. The seroprevalence of the disease was 27.6% in CATT/Trypanosoma evansi test. In Ethiopia, it was for the first time that trypanosomes from dourine suspected...
Light and electron microscopy studies of the midgut and salivary glands of second and third instars of the horse stomach bot, Gasterophilus intestinalis. A morphological study of the midgut and salivary glands of second and third instars of Gasterophilus intestinalis (De Geer) (Diptera: Oestridae) was conducted by light, scanning and transmission electron microscopy. The midgut is anteriorly delimited by a proventriculus, without caeca, and is composed of posterior foregut and anterior midgut tissue from which a double-layered peritrophic matrix is produced. The midgut can be divided into anterior, median and posterior regions on the basis of the structural and physiological variations of the columnar cells which occur along its length. Two oth...
Lumbosacral spinal cord somatosensory evoked potentials for quantification of nociception in horses. There is a need for objective evaluation and quantification of the efficacy of analgesic drugs and analgesic techniques in horses. Objective: To determine whether lumbosacral spinal cord somatosensory evoked potentials (SSEP) can be a useful and reliable tool to assess nociception in equines. Methods: SSEPs and electromyograms (EMG) from the epaxial muscles were recorded simultaneously, following electrical stimulation applied to the distal hindlimb in lightly anaesthetised Shetland ponies (n=7). In order to validate the model, the effect of increasing stimulus intensity was documented and the...
Pathological changes caused by Anoplocephala perfoliata in the equine ileocecal junction. Gastrointestinal motility disorders represent a significant cause of morbidity and mortality in horses. Previously regarded as a non-pathogenic tapeworm, Anoplocephala perfoliata has been recently associated with equine colic. In this study, pathological changes related to A. perfoliata at the ileocecal junction were investigated in 31 slaughtered horses. Our results showed a significant relationship between parasitic burden and grading of histopathological lesions in both the mucosa and submucosa. Moreover, in infested horses, hypertrophy of the circular muscle layer was determined. Finally, ...
