Strongyles are parasitic nematodes that commonly infect horses, residing primarily in the large intestine. They are classified into two groups: large strongyles (Strongylus spp.) and small strongyles (cyathostomins). These parasites are a significant concern in equine health due to their potential to cause gastrointestinal disturbances. Large strongyles can lead to severe damage by migrating through the horse's tissues during their life cycle, whereas small strongyles remain within the intestinal lining and can cause inflammation and colic. Diagnosis and management of strongyle infections involve fecal egg counts and strategic deworming programs. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, epidemiology, and control strategies of strongyles in horses.
Forteau L, Dumont B, Sallé G, Bigot G, Fleurance G.Strongyle infection is an important issue in horse breeding. It impairs horse health and performance, with young horses being the most sensitive. Strongyle control has long relied on the systematic use of chemical treatments. However, expanding anthelmintic resistance among strongyles calls for alternative options. Mixed grazing is assumed to reduce strongyle load on the pasture as the result of a dilution effect. This has been shown in small ruminants grazing with cattle, but the putative benefits of co-grazing between horses and cattle have not yet been evaluated. Here, we conducted field su...
Gonzales-Viera O, Fritz H, Mete A.A 7-month-old female mixed breed foal with a 2-day history of recumbency and inability to open its mouth convulsed acutely and died and was submitted for necropsy examination. The foal was thin and large patches of haemorrhage were present throughout the peritoneal wall, the diaphragmatic surfaces and the retroperitoneum. Numerous nematode larvae were visible on the serosal surfaces and penetrated and embedded into the subserosa associated with the haemorrhages. The dorsal portion of the abdominal diaphragm had a partial tear and large numbers of nematodes were within the muscle fibres. Histol...
Hautala K, Näreaho A, Kauppinen O, Nielsen MK, Sukura A, Rajala-Schultz PJ.Gastrointestinal parasites, Parascaris sp. and strongyles, are common in young horses worldwide and control of these parasites is challenged by increasing anthelmintic resistance. Our aim was to identify risk factors for these infections as well as to assess the efficacy of fenbendazole (dose 7.5 mg/kg) and pyrantel embonate (dose 19 mg/kg) against Parascaris sp. We also evaluated association between owner observed symptoms and patent infections with these parasites. Fecal samples were collected from 367 young horses in Finland and a questionnaire study was conducted. Fecal egg counts were...
Beata Byczkowska , Bogumiła Pilarczyk , Agnieszka Tomza-Marciniak .The emergence of drug resistance among parasites is a side effect of the common use of chemotherapeutic agents in horses. Combating parasites typically involves routine deworming treatments twice a year (before and after the grazing season). However, in grazing farming this treatment may be insufficient. The aim of the study was to evaluate the effectiveness of programs to combat the invasion of strongyles (Strongylidae) in horses in the selected stables of Western Pomerania. Coprological examination was conducted in 85 horses from three stables located in Western Pomerania. Horses from all th...
Nápravníková J, Petrtýl M, Stupka R, Vadlejch J.The detection and quantification of nematode eggs using fecal egg count techniques have an irreplaceable role in equine parasitic control. The reliability, particularly precision and accuracy, of individual techniques have been described only for strongylid infections. The aim of this study was to compare three fecal egg count techniques used for the detection of the two most common equine nematode infections: strongylid and ascarid. The Simple McMaster, Concentration McMaster and Mini-FLOTAC techniques were tested on spiked fecal samples with various levels of egg concentration (50, 100, 200,...
Prado Silva RH, Carneiro de Rezende AS, Ferreira WM, Bastianetto E, Mello MM, Pereira de Abreu A, Farinelli F, Colares de Araújo Moreira D....Weanlings undergo rapid body development in the first year of life and, in this period, are more susceptible to helminth infection that can impair their growth. The objective of this study was to compare the apparent digestibility of nutrients, blood parameters, and body development of deworming and not deworming weanlings. Fourteen Mangalarga Marchador weanling colts, on a farm in Northern Minas Gerais, Brazil, were divided into two groups: dewormed (D) and not dewormed (ND) groups. The weanlings were kept separately for 3 months in two pastures of Cynodon nlemfuensis cv. African Star Grass....
Tydén E, Enemark HL, Franko MA, Höglund J, Osterman-Lind E.Strongylus vulgaris is considered the most pathogenic nematode parasite of the horse. Frequent deworming programs since the 1970s have reduced the prevalence of S. vulgaris to low levels, but to the price of widespread benzimidazole resistance in the small strongyles (cyathostominae) and ivermectin resistance especially in the equine roundworm Parascaris spp. To slow down the progression of anthelmintic resistance in Sweden, horse anthelmintics were made prescription only medicine in 2007 and selective therapy principles were introduced. This means that only individuals with high egg excretion...
Tydén E, Enemark HL, Franko MA, Höglund J, Osterman-Lind E.Strongylus vulgaris is considered the most pathogenic nematode parasite of the horse. Frequent deworming programs since the 1970s have reduced the prevalence of S. vulgaris to low levels, but to the price of widespread benzimidazole resistance in the small strongyles (cyathostominae) and ivermectin resistance especially in the equine roundworm Parascaris spp. To slow down the progression of anthelmintic resistance in Sweden, horse anthelmintics were made prescription only medicine in 2007 and selective therapy principles were introduced. This means that only individuals with high egg excretion...
Wilkes EJA, Woodgate RG, Raidal SL, Hughes KJ.This study investigated the impact of variability in Parascaris spp. and strongyle faecal egg counts (FEC) from foals on treatment decision-making and detection of a patent infection. A single faecal sample was collected once daily for three days from 53 foals and a FEC was performed on three separate portions of each sample (total of nine egg counts per foal). Differences in the decision to administer an anthelmintic using the results of a single count (C), the mean of three (X¯) or nine counts (X¯) and the upper 5% confidence limit of the gamma confidence interval (CI) of the estimate of t...
Ramírez-Hernández A, Polo G, Robayo-Sánchez LN, Cruz-Maldonado OA, Imbacuán-Pantoja WO, Cortés-Vecino JA.Working equids are used in different countries for numerous purposes and regularly are crucial for multiple communities' income and profit. Historically, in Bogotá D.C. they were used as animal-powered vehicles but in 2013 it was initiated a substitution and adoption program as a result of society pressure and lawful processes. Infectious diseases and mainly parasitic diseases, poses a threat in the health and productivity of these animals. Our aim was to identify, by coproparasitological methods, the gastrointestinal and pulmonary parasite species infecting working horses submitted to the me...
Gold S, Regan CE, McLoughlin PD, Gilleard JS, Wilson AJ, Poissant J.Variability in host resistance or tolerance to parasites is nearly ubiquitous, and is of key significance in understanding the evolutionary processes shaping host-parasite interactions. While ample research has been conducted on the genetics of parasite burden in livestock, relatively little has been done in free-living populations. Here, we investigate the sources of (co)variation in strongyle nematode faecal egg count (FEC) and body condition in Sable Island horses, a feral population in which parasite burden has previously been shown to negatively correlate with body condition. We used the ...
Mitchell CJ, O'Sullivan CM, Pinloche E, Wilkinson T, Morphew RM, McEwan NR.Next-generation sequencing of DNA from nematode eggs has been utilised to give the first account of the equine 'nemabiome'. In all equine faecal samples investigated, multiple species of Strongylidae were detected, ranging from 7.5 (SEM 0.79) with 99+% identity to sequences in the NCBI database to 13.3 (SEM 0.80) with 90+% identity. This range is typical of the number of species described previously in morphological studies using large quantities of digesta per animal. However, the current method is non-invasive; relies on DNA analysis, avoiding the need for specialist microscopy identificatio...
Bredtmann CM, Krücken J, Murugaiyan J, Balard A, Hofer H, Kuzmina TA, von Samson-Himmelstjerna G.Rapid, cost-effective, efficient, and reliable helminth species identification is of considerable importance to understand host-parasite interactions, clinical disease, and drug resistance. Cyathostomins (Nematoda: Strongylidae) are considered to be the most important equine parasites, yet research on this group is hampered by the large number of 50 morphologically differentiated species, their occurrence in mixed infections with often more than 10 species and the difficulties associated with conventional identification methods. Here, MALDI-TOF MS, previously successfully applied to identify n...
Harvey AM, Meggiolaro MN, Hall E, Watts ET, Ramp D, Šlapeta J.Australia has over 400,000 wild horses, the largest wild equid population in the world, scattered across a range of different habitats. We hypothesised that wild horse populations unexposed to anthelmintics would have a high prevalence of infections. Verminous endarteritis and colic due to migrating larvae is now absent or unreported in domestic horses in Australia, yet wild horses may pose a risk for its re-emergence. A total of 289 faecal egg counts (FECs) were performed across six remote wild horse populations in south-east Australia, of varying densities, herd sizes and habitats. Total s...
Sperl C, Gerber V, Drießlein D, Klima A, Becher AM.Respiratory signs or more specifically severe equine asthma (SEA) is in some studies reported to be associated with decreased strongyle egg shedding. This association can be reproduced in a larger population of unrelated horses. The owners of 209 horses, on seven farms in Bavaria, were interviewed using, an in prior studies validated questionnaire. Horses were categorized into classes of the horse owner assessed respiratory signs index (HOARSI 1-4, unaffected to severely affected). In total, 1,035 fecal samples were analyzed between March 2011 and September 2014 using a modified McMaster proce...
Raza A, Qamar AG, Hayat K, Ashraf S, Williams AR.Control of equine nematodes has relied on benzimidazoles (BZs), tetrahydropyrimidines and macrocyclic lactones. The intensive use of anthelmintics has led to the development of anthelmintic resistance (AR) in equine cyathostomins and Parascaris equorum. Field studies indicate that BZ and pyrantel resistance is widespread in cyathostomins and there are also increasing reports of resistance to macrocyclic lactones in cyathostomins and P. equorum. The unavailability of reliable laboratory-based techniques for detecting resistance further augments the problem of nematode control in horses. The onl...
Buono F, Pacifico L, Piantedosi D, Sgroi G, Neola B, Roncoroni C, Genovese A, Rufrano D, Veneziano V.Intestinal strongyles are the most common endoparasites of horses, and anthelmintic treatments are the main strategy to control these nematodes. However, the development of anthelmintic resistance has led to a decreased efficacy of synthetic drugs, and for this reason, there is a growing interest in alternative control strategies as the use of medicinal plants. The aim of the present study was to determine the in vivo efficacy of garlic (Allium sativum) in horses naturally infected by intestinal strongyles. The field trial was conducted in a horse trotter farm in Southern Italy. Fifteen mares...
Tedla M, Abichu B.A cross sectional study was conducted in Jimma town from October 2010 to March 2011 with the objective of determining the status of intestinal nematode parasites of equids, and the association of different variables with infection rate. To address this, a total of 400 equids; donkeys (n = 29), horses (n = 317) and mules (n = 54) were used in this study and based on the coprological examination to identify parasite eggs, three species of nematodes were identified with an overall prevalence of 72.25%. A prevalence of 63.25%, 16.50%, 4.25%, and 10.75% were identified for Strongyles, ,...
Went HA, Scare JA, Steuer AE, Nielsen MK.Recommendations for control of equine strongylid parasites are based on regular determination of fecal egg counts to identify high strongylid shedders and to evaluate treatment efficacy. The McMaster technique has long been used as the standard egg counting technique in equine veterinary practice in most parts of the world, but recent work has found the Mini-FLOTAC technique to perform with significantly better accuracy and precision. The Mini-FLOTAC system comes with a homogenizing device, termed the Fill-FLOTAC, and it has been hypothesized that this device might have a significant impact on...
Scare JA, Steuer AE, Gravatte HS, Kálmán C, Ramires L, Dias de Castro LL, Norris JK, Miller F, Camargo F, Lawyer A, De Pedro P, Jolly B, Nielsen MK.Anthelmintic resistance among cyathostomin parasites is a wide-spread problem. The parasite control guidelines written by the American Association of Equine Practitioners (AAEP) encourages the preservation of anthelmintic efficacy by reducing treatment frequency, using targeted deworming, and implementing environmental management practices. While there is knowledge regarding parasite management practices of affluent horse farms in the United States, surveys rarely explore the rural and underserved regions. The purpose of this study was to observe the management practices of horse farms in rura...
Norris JK, Steuer AE, Gravatte HS, Slusarewicz P, Bellaw JL, Scare JA, Nielsen MK.Given the ever-increasing levels of anthelmintic resistance in livestock parasites globally, it is recommended to use parasite fecal egg counts to make treatment decisions and to evaluate treatment efficacy. The consensus in equine parasitology is to use a flotation medium with a specific gravity (SG) of ≥ 1.20 to float the main parasite egg types of interest in egg counting techniques. However, the density of common equine endoparasite eggs has been sparsely investigated. Equine tapeworm eggs are known to be particularly difficult to determine and count in fecal samples. It is unknown wheth...
Nielsen MK, Branan MA, Wiedenheft AM, Digianantonio R, Scare JA, Bellaw JL, Garber LP, Kopral CA, Phillippi-Taylor AM, Traub-Dargatz JL.Equine strongyle parasites are ubiquitous in grazing equids across the world. Anthelmintic resistance is widely developed in cyathostomin populations, but very few surveys have evaluated anthelmintic efficacy in equine populations in the United States, and most of these are over 15 years old. The present study was carried out as part of the National Animal Health Monitoring Systems (NAHMS) Equine 2015-2016 study. The aims were to investigate anthelmintic treatment efficacy by means of the fecal egg count reduction test (FECRT) and identify parameters associated with decreased efficacy. Data we...
Palomero AM, Hernández JA, Cazapal-Monteiro CF, Balán FA, Silva MI, Paz-Silva A, Sánchez-Andrade R, Vázquez MSA.The integrated control of strongyles was assayed for a period of three years in wild equids (zebras, European donkeys, and African wild asses) captive in a zoo and infected by strongyles. During three years control of parasites consisted of deworming with ivermectin + praziquantel; equids also received every two days commercial nutritional pellets containing a blend of 10 - 10 spores of the fungi + per kg meal. Coprological analyses were done monthly to establish the counts of eggs of strongyles per gram of feces (EPG). The reductions in the fecal egg counts (FECR) and in the positive horses...
Nielsen MK, Branan MA, Wiedenheft AM, Digianantonio R, Scare JA, Bellaw JL, Garber LP, Kopral CA, Phillippi-Taylor AM, Traub-Dargatz JL.Equine strongyle parasites are considered ubiquitous in grazing equids across the world, and cyathostomin parasites are known pathogens causing well-described disease complexes in horses. Decades of intensive anthelmintic treatments have led to anthelmintic resistance in cyathostomins, and current recommendations are to lower treatment intensity and base control strategies on fecal egg count surveillance. Little is known about risk factors associated with strongyle parasite egg shedding patterns in the United States equine population, as the most recent national survey was conducted 20 years a...
Costa PWLD, Vilela VLR, Feitosa TF.The objective of this study was to determine the parasitological profiles of traction equids from the semi-arid climate of Paraíba (PB) State. We analyzed 96 equids that performed traction work, with no defined breed, males and females, and all older than 24 months. Among the analyzed animals, 51% were donkeys, 41.7% mules, and 7.3% horses. Fecal material and blood were collected for parasitological examination and to determine the packed cell volume (PCV), respectively. The samples were sent to the Veterinary Parasitology Laboratory, Veterinary Hospital - IFPB, Sousa-PB campus, and epidemiol...
Tavassoli M, Jalilzadeh-Amin G, Fard VRB, Esfandiarpour R.The high incidence of equine gastrointestinal worms and their increased resistance against anthelmintics has encouraged research into the effectiveness of rational phytotherapy. This study investigates the in vitro anti-parasitic effects of extracts of Ferula asafoetida and Allium sativum, two native plants that are widespread in Iran on Strongylus spp. larvae. Faecal samples were collected from horses, examined by routine parasitology methods and positive samples were used for future examination. After incubation, the third-stage larvae were harvested by the Baermann technique. A hydroalcohol...
Sallé G, Kornaś S, Basiaga M.Equine strongyles are a major health issue. Large strongyles can cause death of horses while cyathostomins (small strongyles) have shown increased resistance to anthelmintics worldwide. Description of strongyle communities have accumulated but little is known about the diversity of these communities and underpinning environmental factors. Strongyles were recovered after ivermectin treatment from 48 horses located in six premises in Poland. Correlation between previously published species fecundity and the observed relative abundance and prevalence were estimated. Significance of horse sex was ...
Hernández JÁ, Sánchez-Andrade R, Cazapal-Monteiro CF, Arroyo FL, Sanchís JM, Paz-Silva A, Arias MS.An approach to preventing strongyle infection in horses was tested, comprising rotational pasturing and the administration of spores of two parasiticidal fungi, Mucor circinelloides and Duddingtonia flagrans. Twenty-two adult Spanish Sport Horses were dewormed with ivermectin (1 mg pour-on/kg body weight) and then randomly divided into three groups. G-1 was maintained with continuous grazing, and G-2 and G-3 were kept on a four-paddock rotation system. Commercial pelleted feed (2.5 kg/horse) was supplied to G-1 and G-2 twice a week; horses in G-3 received pellets containing 2 × 10 spores/kg o...
Misuno E, Clark CR, Anderson SL, Jenkins E, Wagner B, Dembek K, Petrie L.The goals of this study were to report the seasonal shedding patterns of strongyle and spp. eggs in repeated fecal samples for mares ( = 38) and foals ( = 39), and to evaluate the efficacy of ivermectin treatment in mares from 2 selected horse breeding farms in central Saskatchewan. Median strongyle fecal egg counts (FEC) peaked in July and August in adult horses. The farms differed significantly ( = 0.0005) in regard to strongyle shedding categories ( 500 eggs/g) over time, but for each individual horse (both farms combined) these categories did not differ over time ( = 0.13) on samples coll...
Christen G, Gerber V, van der Kolk JH, Frey CF, Fouché N.Pituitary pars intermedia dysfunction (PPID) has been associated with diminished immune response in aged horses. This prospective study hypothesised that this may result in increased strongyle egg shedding in affected animals and that horses treated with pergolide would have reduced fecal egg counts (eggs per gram, EPG) compared to placebo-treated animals. Adrenocorticotropic hormone (ACTH) concentrations and EPG were tested in 48 horses. There were no significant differences in baseline EPG between horses with pre-clinical PPID and healthy controls. There was no significant difference in EPG ...
Scala A, Tamponi C, Sanna G, Predieri G, Dessì G, Sedda G, Buono F, Cappai MG, Veneziano V, Varcasia A.Current equine helminth control strategies play a key role in strongyle epidemiology and anthelmintic resistance and have led to the recommendation for new treatment plans, which include diagnostic and efficacy surveillance. Assessing the equine strongyle distribution patterns would thus be useful and this study describes the strongyle prevalence in the equine population in Italy through coprological analysis and coproculture. In addition, individual data on each animal were collected in order to identify risk factors associated with strongyle egg shedding. Of the total number of stables inves...
Döpfer D, Kerssens CM, Meijer YG, Boersema JH, Eysker M.Faeces of 484 horses were sampled twice with an interval of 6 weeks while anthelmintic therapy was halted. Faecal eggs counts revealed that 267 (55.2%) horses had consistently low numbers of eggs per gram faeces (EPG) (EPG 100). Horses with consistently high EPGs were more often mares with access to pasture, aged less than 6 or more than 23 years, that were dewormed at intervals longer than 6 months, and were treated for the last time more than 3 months before the start of the study. Horses with consistently low EPGs were more often male horses with no or limited access to pasture, that were ...
Monahan CM, Chapman MR, Taylor HW, French DD, Klei TR.Two dosages of moxidectin oral gel were evaluated and compared to a therapeutic dose of ivermectin oral paste in the control of a spectrum of gastrointestinal parasites of ponies naturally infected in southern Louisiana or Mississippi. Thirty-two mixed-breed ponies ranging in age from one to 21 years were used in this controlled test. Eight weeks prior to the experiment, ponies grazing on contaminated pasture were moved to a paddock and fed a pelleted ration, thus reducing or eliminating the potential for additional infection and ensuring the existence of a population of encysted larvae. Ponie...
Matthee S, McGeoch MA.The current level of anthelmintic resistance in the horse-breeding industry is extremely high and therefore more emphasis is being placed on studies that focus on the judicious use of anthelmintic products. The aims of the study were to: 1) establish if there is variation in the egg excretion pattern of strongyles between the different age classes of Thoroughbred horses in the Western Cape Province (WCP), 2) test if a selective treatment approach successfully reduces the number of anthelmintic treatments and maintains acceptably low helminth burdens in adult Thoroughbred horses, and 3) evaluat...
Sallé G, Kornaś S, Basiaga M.Equine strongyles are a major health issue. Large strongyles can cause death of horses while cyathostomins (small strongyles) have shown increased resistance to anthelmintics worldwide. Description of strongyle communities have accumulated but little is known about the diversity of these communities and underpinning environmental factors. Strongyles were recovered after ivermectin treatment from 48 horses located in six premises in Poland. Correlation between previously published species fecundity and the observed relative abundance and prevalence were estimated. Significance of horse sex was ...
Fabiani JV, Lyons ET, Nielsen MK.Parasite control in foals is of utmost importance due to the high susceptibility to parasitic infection and disease in this age group. Foals are commonly co-infected with strongyle and ascarid parasites, which complicate parasite control strategies. The present study retrospectively investigated necropsy records of foals born into a university herd kept without anthelmintic treatment since 1979. The aims were to statistically analyze the relationship between fecal egg counts, worm burdens, foal age, sex, and season with specific focus on Parascaris and Strongylus spp. A total of 83 foals born ...
Vidyashankar AN, Hanlon BM, Kaplan RM.Anthelmintic resistance (AR) is a serious problem for the control of equine gastrointestinal nematodes, particularly in the cyathostomins. The fecal egg count reduction test (FECRT) is the most common method for diagnosing AR and serves as the practical gold standard. However, accurate quantification of resistance and especially accurate diagnosis of emerging resistance to avermectin/milbemycin (A/M) drugs, is hampered by a lack of accepted standards for study design, data analysis, and data interpretation. In order to develop rational evidence-based standards for diagnosis of resistance, one ...
Studzińska MB, Tomczuk K, Demkowska-Kutrzepa M, Szczepaniak K.Postmortem parasitic examinations of the large intestines of 725 slaughtered horses from individual farmers in southeastern Poland were carried out. The examinations were carried out monthly since February 2006 until January 2007 (except for August 2007 because of a technological stoppage in the slaughterhouse). The examinations included the intensiveness and extensiveness of the infestation of the Strongylidae belonging to the Strongylus genus. The Strongylidae were found in 26.5% of the examined horses. Strongylus vulgaris was the most dominant nematode and had a 22.8% prevalence, Strongylus...
The Journal of parasitologyMay 23, 2003
Volume 89, Issue 2 309-314 doi: 10.1645/0022-3395(2003)089[0309:POSNIN]2.0.CO;2
Chapman MR, French DD, Klei TR.One hundred and seventeen ponies were surveyed for the seasonal prevalence of strongyloid parasites, particularly cyathostomes, and for host- and age-related differences in these infections. For 56 ponies, all stages of the cyathostome life cycle, both mucosal and luminal, were enumerated. Total numbers of cyathostomes and percentage of developing larvae (DL) encysted in the mucosa remained constant in all 4 seasons of the year, whereas a significant increase in the percentage of adults in the cyathostome population occurred in fall. In yearling ponies, encysted early third-stage larvae consti...
Daniels SP, Leng J, Swann JR, Proudman CJ.Anthelmintic treatment is a risk factor for intestinal disease in the horse, known as colic. However the mechanisms involved in the onset of disease post anthelmintic treatment are unknown. The interaction between anthelmintic drugs and the gut microbiota may be associated with this observed increase in risk of colic. Little is known about the interaction between gut microbiota and anthelmintics and how treatment may alter microbiome function. The objectives of this study were: To characterise (1) faecal microbiota, (2) feed fermentation kinetics in vitro and (3) metabolic profiles following m...
Scheuerle MC, Stear MJ, Honeder A, Becher AM, Pfister K.The selective treatment of horses is used to decrease the number of anthelmintic treatments by only treating a proportion of animals in the population. One way to select animals for treatment is to identify low and high egg-shedders using faecal egg counts (FEC); then to treat only the high egg-shedders. The value of this method is enhanced if differences among individuals in the level of egg-shedding remain consistent over time. One way to assess the stability of the rankings of animals over time is to measure the repeatability which is defined as the variance between horses divided by the to...
Hodgkinson JE, Freeman KL, Lichtenfels JR, Palfreman S, Love S, Matthews JB.The efficacy of five daily fenbendazole (FBZ) treatments was tested against benzimidazole-resistant cyathostomins in naturally infected horses (n=13). Horses were treated with pyrantel embonate (PYR) to remove adult strongyles followed, 7 days later, by a 5-day course of FBZ. The PYR treatment produced an average faecal egg count reduction of 98%. All samples were negative by faecal egg count 7 days after the start of the FBZ treatment. Positive egg counts were observed from 28 days after the start of FBZ treatment and all horses displayed positive faecal egg counts by 77 days after treatment....
Osterman Lind E, Eysker M, Nilsson O, Uggla A, Höglund J.This study was conducted on a stud farm in Sweden to investigate the species composition of cyathostomins expelled in the faeces of horses after deworming using three different anthelmintic preparations. Twenty-seven horses excreting > or = 200 strongyle eggs per gram faeces (EPG) were divided into three comparable groups and dewormed on day 0 with either of following compounds: 0.2 mg ivermectin per kg body weight (bw), 19 mg pyrantel pamoate per kg bw or 7.5 mg fenbendazole per kg bw. For each of the 3 days following anthelmintic treatment faeces was collected from individual horses and s...
Demeulenaere D, Vercruysse J, Dorny P, Claerebout E.The control of naturally acquired cyathostome infections in horses by treatments with ivermectin and moxidectin was evaluated in three field studies. In a first study the efficacy of both drugs was assessed in a faecal egg count reduction test. Both ivermectin and moxidectin demonstrated efficacies greater than 99 per cent for up to 60 days after treatment. In a second study, the period required for strongyle eggs to reappear was estimated in horses treated either with ivermectin or moxidectin. For the horses treated with ivermectin the period varied between 10 and approximately 13 weeks, and ...
Lyons ET, Tolliver SC, Collins SS.Fecal samples (n=1,584) for a parasite study were collected from Thoroughbred foals (n=349), 28 to 330 days old, on seven farms in central Kentucky during 49 monthly trips from May to October, November, or December 2004. The main purpose was to determine possible drug resistance of ascarids, also of strongyles, to ivermectin (IVM) and other commercially available compounds [fenbendazole, moxidectin (MOX), oxibendazole (OBZ), and pyrantel pamoate]. In addition, interest was on prevalence of foal parasites. Qualitative data were obtained by recording presence or absence of ascarid and strongyle ...
Ehizibolo DO, Kamani J, Ehizibolo PO, Egwu KO, Dogo GI, Salami-Shinaba JO.This study was conducted to determine the prevalence and significance of parasites of horses in northern Nigeria. Blood and faecal samples were randomly collected from 243 horses from different stables in some states of northern Nigeria for laboratory analyses. Fifty-seven horses (23.5%) were found infected with parasites. The hemoparasites detected, 21 (8.6%), include Theileria equi, Babesia caballi, Trypanosoma vivax and Trypanosoma evansi. The endoparasites encountered, 29 (11.9%) were Strongylus spp., Strongyloides spp., Oxyuris equi, Parascaris equorum, Paragonimus spp. and Dicrocoelium s...
Lyons ET, Tolliver SC, Collins SS, Ionita M, Kuzmina TA, Rossano M.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...
Nielsen MK, Branan MA, Wiedenheft AM, Digianantonio R, Scare JA, Bellaw JL, Garber LP, Kopral CA, Phillippi-Taylor AM, Traub-Dargatz JL.Equine strongyle parasites are considered ubiquitous in grazing equids across the world, and cyathostomin parasites are known pathogens causing well-described disease complexes in horses. Decades of intensive anthelmintic treatments have led to anthelmintic resistance in cyathostomins, and current recommendations are to lower treatment intensity and base control strategies on fecal egg count surveillance. Little is known about risk factors associated with strongyle parasite egg shedding patterns in the United States equine population, as the most recent national survey was conducted 20 years a...
Nielsen MK, Olsen SN, Lyons ET, Monrad J, Thamsborg SM.Strongyle parasites are ubiquitous in grazing horses, and the large strongyle Strongylus vulgaris is considered the most pathogenic helminth parasite of horses. Recent investigations have suggested an association between occurrence of this parasite and usage of selective therapy based on regular fecal egg counts. The established diagnostic method for S. vulgaris involves larval culture and subsequent morphological identification of third stage larvae under the microscope. Recently, a real-time PCR assay was developed and validated for the detection and semi-quantification of S. vulgaris eggs i...
Al Anazi AD, Alyousif MS.This study aimed to provide recent data on the occurrence of non-strongyle intestinal parasite infestation in horses in the Riyadh region of Saudi Arabia as a basis for developing parasite control strategies. We conducted necropsy for 45 horses from September 2006 to November 2007 in the Riyadh region, Saudi Arabia. 39 out of 45 horses were infected with intestinal parasites with an infestation rate of 86.6%. Infestations with seven nematode species and two species of Gasterophilus larva were found. The most prevalent parasites were Strongyloides westeri (64.4%) and Parascaris equorum (28.8%) ...
Abo-Aziza FAM, Hendawy SHM, Namaky AHE, Ashry HM.The aim of this study was to investigate the early diagnosis of strongyle infection based on early changes in Th1 and Th2 cytokines beside the diagnostic accuracy values and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting profiles using prepared strongyles antigens. Methods: A total of 73 donkeys had a mean age of 4-32 years old were parasitologically examined for strongyle infection. The early changes in Th1 and Th2 cytokines were determined, and the diagnostic accuracy values and SDS-PAGE and western blotting profiles were performed using prepared st...
Lyons ET, Tolliver SC.Prevalence of internal parasites was determined by fecal examination for eggs and oocysts in Thoroughbred foals in central Kentucky in 2003. Fecal samples were examined from 733 foals on 14 farms. This included 70 trips to the farms and a total of 2,346 fecal samplings. Monthly collection of fecal samples was begun for four farms in February, six in March, three in April, and one farm in May. Termination of the study for all farms was the end of July. A criterion was that the foals be at least 10 days old for initial samplings. If available, the same foals were sampled each time, in addition t...
Smith HJ.A group of seven ponies naturally infected with large numbers of small strongyles and raised under conditions to minimize reinfection were treated periodically over a three year span with thiabendazole at the rate of 44 mg/kg body weight. Based on the absence of worm eggs in the feces following each treatment, thiabendazole removed the adult strongyles present with a new population subsequently developing by maturation of inhibited larvae. It took as many as four or five treatments to eliminate or reduce significantly the worm burdens present in the ponies under the conditions of this study. S...
McCraw BM, Slocombe JO.Pony foals inoculated with infective Strongylus edentatus larvae were monitored for clinical signs and selected blood changes and were examined at necropsy from two to 56 days postinfection. Larvae penetrated the intestine and reached the liver intravenously before 40 hours postinfection. Occasional thrombi and larval tracks associated with the intima of cecal and colic veins suggested aberrant paths. Larvae in the liver doubled in width between seven and 15 days postinfection and a sudden increment in circulating eosinophils occurred between 11 and 15 days. These changes were probably associa...
Cain JL, Slusarewicz P, Rutledge MH, McVey MR, Wielgus KM, Zynda HM, Wehling LM, Scare JA, Steuer AE, Nielsen MK.Fecal egg counts are the cornerstone of equine parasite control programs. Previous work led to the development of an automated, image-analysis-based parasite egg counting system. The system has been further developed to include an automated reagent dispenser unit and a custom camera (CC) unit that generates higher resolution images, as well as a particle shape analysis (PSA) algorithm and machine learning (ML) algorithm. The first aim of this study was to conduct a comprehensive comparison of method precision between the original smartphone (SP) unit with the PSA algorithm, CC/PSA, CC/ML, and ...
Krecek RC, Reinecke RK, Horak IG.Between 1980 and 1982, the gastrointestinal tracts of 17 horses which had been grazing on mixed grassveld at Potchefstroom and bushveld at Onderstepoort in the province of Transvaal, Republic of South Africa, were examined at necropsy and processed for parasite recovery. The large strongyles and their prevalences were as follows: Strongylus vulgaris and associated lesions (88-94%), Strongylus edentatus (24%), Strongylus equinus (30%), Triodontophorus nipponicus (35%) and Craterostomum acuticaudatum (18%). The seven most prevalent and abundant cyathostomes collected were Cylicostephanus longibu...
Lyons ET, Tolliver SC.Critical tests were performed in 2011 in four weanling horses (L-1, L-2, L-29, and L-30) treated with ivermectin paste at 200 μg/kg. They were born in 2011 and raised together on a farm (MC) in Central Kentucky. The horses had not been treated previously with an antiparasitic drug. However, ivermectin had been administered repeatedly to the horse herd for several years and strongyle eggs per gram of feces (EPGs) returned sooner posttreatment than after initial usage. Critical tests in a recent previous study in this horse herd indicated that the reason for the early return of strongyle EPGs a...
Upjohn MM, Shipton K, Lerotholi T, Attwood G, Verheyen KL.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...
Becher AM, Mahling M, Nielsen MK, Pfister K.For 9 consecutive months (March-November 2008), faecal samples were collected monthly from 129 horses residing within 40 km of Salzburg, Austria. Samples were analysed quantitatively using a modified McMaster egg counting technique. Whenever a faecal egg count (FEC) result exceeded 250 eggs per gram (EPG), the horse was treated with pyrantel, ivermectin or moxidectin. In 52 of 129 horses (40.3%), no strongyle eggs were ever detected over the course of 9 months. In 39 horses (30.2%), strongyle eggs were detected in at least 1 sample, but the egg count never exceeded 250 EPG. The remaining 38 (2...
Two closed horse herds (Old Lot 4 and Field 24), infected since 1966 with Population B small strongyles resistant to thiabendazole (TBZ) and phenothiazine (PTZ), were terminated in February, March, and May, 2005. At necropsy, only the large endoparasites were identified and counted. The number of horses on pasture was 14 (239 days of age to 23 years old) for Old Lot 4 and two (3 to 20 years old) for Field 24. The time of the last antiparasitic treatment, relative to the year (2005) of necropsy, was 26 years for Old Lot 4 and 9 years for Field 24 horses. Gasterophilus intestinalis third instars...
