Fecal Egg Count (FEC) is a diagnostic tool used to quantify the number of parasite eggs present in a horse's feces. This measure is primarily employed to assess the burden of gastrointestinal parasites, such as strongyles and ascarids, in equine populations. FEC is instrumental in informing parasite management strategies, including the timing and effectiveness of anthelmintic treatments. The process involves collecting a fecal sample from the horse, preparing it in a laboratory setting, and examining it under a microscope to count the eggs. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and implications of fecal egg count in equine parasitology.
DeBel NA, Yalavarthi G, Johnson JR, Simoneau AT, Sweeney B, Stearns G, Saliceti A, Rutstein H, Amalaradjou MA, Govoni KE, McBride ZG, Moore TE....Strongyles are nematode parasites that affect the large intestine and cecum of the horse, with symptoms ranging from poor hair coat to colic. This can influence gut health, nutrient absorption, and overall body condition. Objective: Determine the effects of parasitic load, breed, age, housing, and season on skin and hair coat conditions. We hypothesized that horses with low fecal egg counts would have better hair and skin coat condition compared with those with high fecal egg counts. Methods: A total of forty-five Morgan and 11 Thoroughbred horses were included in this study. We tested the eff...
Nixon W, Buckley P, Butler R.There is a lack of information on horse parasite management practices currently used by individual horse owners in Australia. A voluntary, anonymous online survey was developed for and distributed by Pony Club Australia to its members seeking information on horse population; housing; paddock, manure and parasite management; and owner attitudes. From a total of 98 completed responses, 95/98 of participants indicated their horses spent time in paddocks, 91/98 administered anthelmintics, 42/98 guessed their horse's body weight for dosing, 78/98 recalled the dewormer brand or active ingredient las...
Zhang C, Cai E, Ma Y, Zhong G, Gao Y, Wu Y, Liu B, Li J.This study investigated the cyathostomin species composition, anthelmintic efficacy, and potential resistance-associated mutations in Chinese grazing horses. Fecal samples were collected from 90 adult horses. Fecal egg counts (FECs) were determined using a modified McMaster method. Third stage larvae (L3) cultured from the eggs were identified to species level by PCR amplification and sequencing of the internal transcribed spacer-2 (ITS-2). The main species included and spp. However, differences in the relative abundance of less common species, including and , suggests regional variation. A...
Cabaret J, Guerrero Molina C, Martínez-Ortiz-de Montellano C, Alcala Canto Y.Faecal egg counts (FECs) are used to assess the intensity of gastrointestinal nematode (GIN) infections in herbivores. FEC distribution is aggregated, meaning that approximately 20% of animals harbour 80% of infections. In times of escalating anthelmintic resistance, it may be necessary to restrict treatment to the animals with the heaviest infections. This strategy is called targeted selective treatment (TST) and is relevant to GIN, for example. The difficulty lies in identifying which animals to treat. One solution is to select potentially at-risk animals based on age (for example, treating ...
Cyathostomins and Anoplocephala perfoliata infect equids worldwide and both are of concern due to their potential to cause clinical disease. Although coprological techniques are commonly used for assessing helminth egg shedding these do not provide information about an individual's total parasite burden. Antibody-based tests provide information on infection levels within individuals. Objective: This study aimed to evaluate cyathostomin and Anoplocephala perfoliata occurrence in Italian horses using coprological and serum-based antibody detection methods and to analyse risk factors for infectio...
Girisgin O, Gülegen E, Girisgin AO, Cirak VY.Anoplocephalid species are responsible for causing tapeworm infection in horses. The disease may cause serious health issues, including discomfort, colic, and even intestinal perforation and death. A study was carried out to compare the detection rates of tapeworm eggs in naturally infected horses using two different examination solutions. For this purpose, faecal samples of 241 horses were examined with a combined sedimentation + centrifugation + flotation technique using saturated sugar solution (specific gravity (SG) = 1.30) as the basis and potassium carbonate (KCO) solution (S...
Jamshidpour R, Nabavi R, Moadab H, Rezaie F, Chale AC, Sargison N.Resistance to benzimidazole (BZ) by cyathostomin nematodes has become a major threat to equine health around the world. We aimed to evaluate the efficacy of BZ drugs against small strongyle nematodes in horses of western Iran using coprological and molecular examination. Unassigned: Faecal egg count reduction tests were performed on 398 horses kept in 16 stables in western Iran (Kermanshah Province), to detect benzimidazole resistance in small strongyle nematodes. Allele-specific PCR was used to identify the F200Y (TAC/TTC) SNP in the beta-tubulin gene codon in cyathostomin larvae. Unassigned:...
Döberl J, Li Z, Furrer R, Jäger MC.Reduced anthelmintic efficacy against small strongyles in horses is a widespread problem, yet recent data is scarce. Objective: This paper aims to investigate the current status of anthelmintic efficacy in the field in Germany, specifically focusing on pyrantel. Methods: The study included 1670 horses for which a total of 1913 dewormings were analysed. Of these, 1682 were performed with pyrantel, 56 with fenbendazole, 162 with macrocyclic lactones and 13 with other compounds (e.g. herbs). The faecal egg count reduction (FECR) was calculated with two methods, the faecal egg count reduction test...
Varandas M, Lozano J, Agrícola R, Gomes L, Rosa T, Magalhães M, Lamas L, Rinaldi L, Oliveira M, Paz-Silva A, Madeira de Carvalho L.The diagnosis of gastrointestinal (GI) strongyle infections in equids is still mainly performed using quantitative coprological techniques, like the McMaster (McM), but more sensitive and precise techniques, like FLOTAC (FL) and Mini-FLOTAC (MF), have been proposed over the past 20 years. The present study aimed to compare the analytical performance of these three methods in the diagnosis of strongyle infections in horses. Between October 2023 and June 2024, 32 fecal samples were processed using the McM, FL and MF techniques to identify strongyles' eggs, estimate their shedding (eggs per gram ...
Klass LG, Diekmann I, Andreotti S, Mbedi S, Sparmann S, Schenk T, Anderson HP, Bellaw J, Nielsen MK, Krücken J, von Samson-Himmelstjerna G.Strongyles, especially non-migratory Strongylidae, are the most common equine gut parasites, and typically occur in mixed infections with 10 - 20 species per host. Current knowledge on strongyle species prevalence and within-host tropism is sparse. Herein species composition of mixed strongyle infections of 12 naturally infected untreated young horses, based on strongyle eggs extracted from faeces, cultured third stage larva and luminal worms collected from ventral and dorsal colon was examined. Species were identified using a cytochrome c oxidase I (COI) metabarcoding approach allowing differ...
Studzińska M, Klockiewicz M, Szczepaniak K, Demkowska-Kutrzepa M, Roczeń-Karczmarz M, Tomczuk K.The resistance of strongyles to pyrantel pamoate has been reported in publications worldwide. There is no data on its efficacy in horses in Poland. Therefore, the aim of this study was to evaluate the effectiveness of pyrantel pamoate to control strongyle invasions in young horses. The study involved horses of both sexes, aged 1 to 2 years, and was conducted in two seasons (spring and the end of summer). Feces were collected 24 hours before and 14 days after deworming, and they were then examined using McMaster's and combined sedimentation-flotation methods. Results revealed that in spring, th...
Silva GLS, Curcio UA, Boufleur JA, Borges DGL, Nakatani MTM, Freitas MG, Borges FA, Faria FJC, Silva RHP, Franco GL.Anthelmintic resistance has led to the use of organic extracts as alternative methods of parasite control. Objective: The study aimed to assess the effects of Acacia mearnsii extract (tannin) on the control of cyathostomins in horses, both in vitro and in vivo. Methods: Thirty Pantaneiro horses naturally infected with cyathostomins were sourced from two distinct farms, designated as Farms A and B. At the start of the study, all third-stage larvae were cyathostomins, and an egg hatchability test (EHT) was performed using fecal samples from horses on both farms. Two randomized 28-day field studi...
Joó K, Csanádi L, Povázsai Á, Nielsen MK.Horses remain globally at constant risk of strongylid infections, with cyathostomins being particularly prevalent and abundant. It is essential to routinely monitor the efficacy of anthelmintics against equine nematodes. This study aimed to evaluate the efficacy of ivermectin against equine strongyles and estimate the strongyle egg reappearance period (ERP) following ivermectin treatment for the first time in Hungary. Fecal samples were collected from 57 Thoroughbred mares before treatment and at 2, 4, 5, 6, and 7 weeks post-treatment at a Hungarian National Stud Farm. Fecal egg counts (FECs)...
Tramboo SR, Shahardar RA, Allaie IM, Bulbul KH.Benzimidazole (BZ) anthelmintics have been used indiscriminately in equids to control nematode infections throughout the world including India and has led to the development of BZ resistance. In order to determine the current status of BZ resistance in equids of Kashmir against intestinal strongyles (IS), the present study was conducted using faecal egg count reduction test (FECRT) and Allele specific PCR (AS-PCR). The study was conducted on ponies from three major tourist destinations of Kashmir viz; Gulmarg, Pahalgam and Sonamarg in accordance with the WAAVP guidelines. The animals which wer...
Sillence MN, Holt K, Li FI, Harris PA, Coyle M, Fitzgerald DM.Ecdysterone controls moulting and reproduction in insects, crustaceans, and helminths. It is also produced by many plants, probably as an insect deterrent. The steroid is not made by vertebrates but has anabolic effects in mammals and could be useful for treating sarcopenia in aged horses. However, ecdysterone is banned in horseracing and equestrian sports, and with no limit of reporting, the risk of unintended exposure to this naturally occurring prohibited substance is a concern. To explore this risk, pasture plants and hay samples were analysed for ecdysterone content, as well as samples of...
Lu Y, Ru P, Qin S, Zhang Y, Fu E, Cai M, Tuohuti N, Wu H, Zhang Y, Zhang Y.Gastrointestinal parasitic diseases pose significant health risks to equine populations. This study investigated the epidemiological patterns of equine gastrointestinal parasites in Xinjiang by analyzing 83 fecal samples collected from Ili ( = 62) and Urumqi ( = 21) between August and November 2024. The modified McMaster technique was employed to quantify fecal egg counts (EPG) and was complemented by morphological identification to assess infection dynamics related to geography, breed specificity, and management practices. The results demonstrated an overall infection prevalence of 66.3% (55/...
Ochigbo GO, Ahn S, Belhumeur KA, Poissant J, Rosa BV.Unmanaged feral horses, naïve to dewormers, offer a unique opportunity to study natural communities of equine parasites. These communities may include parasites that are rare in managed populations, and these may be transmitted to domestic horses in areas where there is contact between feral and domestic equine populations. There have been only a few studies of gastrointestinal parasite populations in horses, and very few from North American equine populations. This study aimed to gain insights into parasite biology through identification of the strongyle parasite species infecting feral hors...
Golamgouse NN.Mauritius hosts a population of approximately 900 equids, but no investigations have delved into issues such as the prevalence of equine helminths, anthelmintic usage, and resistance emergence. This study aimed to devise a qualitative and quantitative profile of common helminthic intestinal parasites in equines at eight out of twenty-eight stables (272 horses, 29 % of local population) and to determine whether helminthic intestinal parasites in equines at one stable have developed resistance to Fenbendazole by quantitatively assessing pre-treatment faecal egg counts, post-treatment faecal egg...
Nielsen MK, Bartholdy ID, Kristensen KS, Borrye JC, Meilvang KSS, Rendtorff CEK, Hjortflod MD, Fuglbjerg V, Karlsson M, Petersen HH, Toft K....Equine strongylids are ubiquitous and can cause severe health issues. Anthelmintic resistance is widely common in cyathostomin parasites, and recent studies have documented increasing incidence of resistance to the macrocyclic lactone drug class. Several European countries have implemented prescription-only restrictions of anthelmintic usage by law to reduce anthelmintic treatment intensity and decrease the selection pressure for drug resistance. However, long term outcomes of this approach have not been thoroughly evaluated. The aim was to determine ivermectin efficacy in strongylids by means...
Nowak AC, Macho-Maschler S, Biermann NM, Palme R, Dengler F.Horses are highly sensitive to stress, which can affect their wellbeing and lead to various health issues. Effective and objective stress assessment is therefore crucial for improving their care and management. The production of the glucocorticoid cortisol is increased in response to stressful stimuli and its metabolites can be measured non-invasively in feces. Therefore, this study aimed to explore the impact of different environmental and physiological stressors on fecal cortisol metabolite (FCM) concentrations in horses, with a particular focus on the relationship between stress, health, an...
Ryu SH, An SJ, Forbes E, Kim BS, Choe S.Equine strongyle infections are prevalent among grazing horses worldwide, yet research on anthelmintic efficacy and parasite management strategies in South Korea remains limited. This study investigated the infection dynamics and parasite burden in horses managed under different systems (pasture vs. stable) over a one-year period in Jeju, South Korea, assessing the impact of management practices on parasite burden and the effectiveness of current deworming regimens. Thirty-two horses were administered ivermectin/praziquantel in June 2022 and assigned to either pasture (n = 16) or stable (n...
de Freitas MG, Dos Santos GH, Silva DLZ, Costa TD, Borges DGL, Reckziegel GH, Cleveland H, do Nascimento Ramos CA, Pereira FB, de Almeida Borges F.The strategic control of equine gastrointestinal nematodes is based on epidemiology. The aim is the reduction of the population of parasites as a whole in the hosts and environment while seeking the number of treatments that achieves the balance between not risking animal health and not exerting selection pressure for resistant parasites. This is the first study in a tropical region to assess a strategic control protocol for equines. The study was conducted in the municipality of Anastácio in the state of Mata Gross do Sul, Brazil, over a two-year period from April 2021 to March 2023, involvi...
Kelly RF, Galbraith E, Zahid O, Chaundhry U, Sargison N.Grazing animal species kept in zoological collections can be at risk of significant gastrointestinal nematode (GIN) infections. Little work has been undertaken to understand GIN species dynamics within co-grazed hosts. This study aimed to describe the species diversity of GINs found in faeces of grazing animals in a Scottish zoological collection. Methods: At a single time-point, freshly voided faecal samples were collected randomly from horses, sheep, goats, alpacas and deer. Faecal worm egg counts (FWECs) were conducted using a saturated saline centrifugal flotation cuvette technique. The ne...
Whitlock F, van Dijk J, Hodgkinson JE, Grewar JD, Newton JR.Anthelmintic resistance (AR) threatens effective equine parasite control. Quarterly data summaries from faecal worm egg count testing (FWECT) performed by UK laboratories have appeared in Equine Quarterly Disease Surveillance Reports (EQDSR) since 2007, but have not previously been assessed. Objective: To assess strongyle FWECT methods and thresholds used by UK laboratories. To investigate factors associated with quarterly laboratory FWECT positivity rates between 2007 and 2023. Methods: Laboratory surveys and analysis of laboratory summary data. Methods: Laboratories were surveyed in Q3 2018 ...
Żak-Bochenek A, Żebrowska-Różańska P, Bajzert J, Łaczmański Ł, Szponar B, Siwińska N, Gładysz K, Sikorska K, Chełmońska-Soyta A.Oral probiotic dietary supplements are widely used in veterinary medicine, including in horses. It is hypothesized that the presence of probiotic strains can both modulate the intestinal microbiota and affect mucosal immunity parameters. Such a study has not yet been conducted in horses. Unassigned: This study involved 12 healthy horses, which were randomly divided into a control group and a group that received a commercial oral probiotic formula containing , or for 84 days. Fecal samples were collected from all horses on day 0 (D0), 28 days after starting the probiotic (D28), 56 days (D56),...
Königová A, Babják M, Kuzmina TA, Burcáková Ľ, Syrota Y, Várady M.The study aimed to conduct a survey on the occurrence of benzimidazole (BZ) resistance in strongyles by in vitro egg hatch test (EHT) and larval development test (LDT) and to identify the effective indicators of early resistance detection on horse farms with associated risk factors analysis appraisal. In total, 203 horses from 8 farms underwent the fecal sampling of which 77 horses were selected for in vitro testing. Simultaneously, 18 horses were chosen to analyse the results of in vitro tests compared to the in vivo fecal egg count reduction test (FECRT). The EHT indicated the presence of re...
Smith MZ, York M, Townsend KS, Martin LM, Gull T, Coghill LM, Ericsson AC, Johnson PJ.Whereas restoration of fecal consistency after treatment with clioquinol for chronic diarrhea and free fecal water syndrome has been attributed to its antiprotozoal properties, actions of clioquinol on the colonic bacterial microbiota have not been investigated. Objective: Characterize the dynamics of fecal microbial diversity before, during, and after PO administration of clioquinol to healthy horses. Methods: Experimental prospective cohort study using a single horse group. Methods: Eight healthy adult horses received PO clioquinol (10 g, daily) for 7 days. Feces were obtained daily for ...
Bull KE, Hodgkinson J, Allen K, Poissant J, Peachey LE.Cyathostomins are the most abundant equid endoparasites globally. There are approximately fifty cyathostomin species and, whilst they occupy distinct niches within the large intestine, they are generally considered to share similar characteristics in terms of pathogenicity and response to drug treatment. There are three classes of anthelmintic licensed in the UK to treat cyathostomins (benzimidazoles, tetrahydropyrimidines and macrocyclic lactones) and cases of resistance have been documented for all classes. Previously, faecal egg count reduction tests (FECRT) on four UK Thoroughbred studs re...
Hamad MH, Jitsamai W, Chinkangsadarn T, Ngangam TS, Wattanapornpilom T, Naraporn D, Ouisuwan S, Taweethavonsawat P.Strongylid nematodes represent a major health and performance concern for equids globally. However, the epidemiology of strongylid infections in horse populations remains largely unexplored in Thailand. This study investigated the prevalence of strongylid parasites and the associated risk factors in domesticated horses in Thailand. Additionally, the study utilized ITS-2 rDNA metabarcoding to characterize the diversity and co-occurrence patterns of strongylid species. Of the 408 horses examined, 50.98% tested positive for strongyle infection, with an average intensity of 445.67 ± 639.58 eg...
Ahn S, Redman EM, Gavriliuc S, Bellaw J, Gilleard JS, McLoughlin PD, Poissant J.Identifying factors that drive among-individual variation in mixed parasitic infections is fundamental to understanding the ecology and evolution of host–parasite interactions. However, a lack of non-invasive diagnostic tools to quantify mixed infections has restricted their investigation for host populations in the wild. This study applied DNA metabarcoding on parasite larvae cultured from faecal samples to characterize mixed strongyle infections of 320 feral horses on Sable Island, Nova Scotia, Canada, in 2014 to test for the influence of host (age, sex and reproductive/social status) and ...
Kaplan RM, Vidyashankar AN.Over the past 10-15 years, we have witnessed a rapid increase in both the prevalence and magnitude of anthelmintic resistance, and this increase appears to be a worldwide phenomenon. Reports of anthelmintic resistance to multiple drugs in individual parasite species, and in multiple parasite species across virtually all livestock hosts, are increasingly common. In addition, since the introduction of ivermectin in 1981, no novel anthelmintic classes were developed and introduced for use in livestock until recently with the launch of monepantel in New Zealand. Thus, livestock producers are often...
Coles GC, Jackson F, Pomroy WE, Prichard RK, von Samson-Himmelstjerna G, Silvestre A, Taylor MA, Vercruysse J.Before revised World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines on the detection of anthelmintic resistance can be produced, validation of modified and new methods is required in laboratories in different parts of the world. There is a great need for improved methods of detection of anthelmintic resistance particularly for the detection of macrocyclic lactone resistance and for the detection of resistant nematodes in cattle. Therefore, revised and new methods are provided here for the detection of anthelmintic resistance in nematodes of ruminants, horses and ...
Kaplan RM, Denwood MJ, Nielsen MK, Thamsborg SM, Torgerson PR, Gilleard JS, Dobson RJ, Vercruysse J, Levecke B.The faecal egg count reduction test (FECRT) remains the method of choice for establishing the efficacy of anthelmintic compounds in the field, including the diagnosis of anthelmintic resistance. We present a guideline for improving the standardization and performance of the FECRT that has four sections. In the first section, we address the major issues relevant to experimental design, choice of faecal egg count (FEC) method, statistical analysis, and interpretation of the FECRT results. In the second section, we make a series of general recommendations that are applicable across all animals ad...
Matthews JB.Anthelmintics have been applied indiscriminately to control horse nematodes for over 40 years. Three broad-spectrum anthelmintic classes are currently registered for nematode control in horses: benzimidazoles (fenbendazole, oxibendazole), tetrahydropyrimidines (pyrantel) and macrocyclic lactones (ivermectin, moxidectin). Generally, control strategies have focused on nematode egg suppression regimens that involve the frequent application of anthelmintics to all horses at intervals based on strongyle egg reappearance periods after treatment. The widespread use of such programmes has substantial...
Kaplan RM.Suppressive anthelmintic treatment strategies originally designed to control Strongylus vulgaris in horses were extremely successful in reducing morbidity and mortality from parasitic disease. Unfortunately, this strategy has inadvertently resulted in the selection of drug-resistant cyathostomes (Cyathostominea), which are now considered the principal parasitic pathogens of horses. Resistance in the cyathostomes to benzimidazole drugs is highly prevalent throughout the world, and resistance to pyrantel appears to be increasingly common. However, there are still no reports of ivermectin resista...
von Samson-Himmelstjerna G, Fritzen B, Demeler J, Schürmann S, Rohn K, Schnieder T, Epe C.In 2003 and 2004, on a total of 63 different German horse farms, a survey using the faecal egg count reduction (FECR) test was performed to investigate the efficacy of ivermectin (IVM, Ivomec) and pyrantel (PYR, Banminth) treatment against gastro-intestinal nematodes in a total of 767 horses. IVM treatment resulted in 100% reduction of the cyathostomin egg production 14 and 21 days post-treatment (d.p.t.) on 37 farms. On the remaining five farms, the mean faecal egg count reduction ranged between 97.7 and 99.9%. The mean cyathostomin FECR following PYR treatment ranged between 92.2 and 100% on...
Nielsen MK, Baptiste KE, Tolliver SC, Collins SS, Lyons ET.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...
Traversa D, von Samson-Himmelstjerna G, Demeler J, Milillo P, Schürmann S, Barnes H, Otranto D, Perrucci S, di Regalbono AF, Beraldo P, Boeckh A....A large survey was carried out in 2008 in Europe to evaluate the efficacy of fenbendazole (FBZ), pyrantel (PYR), ivermectin (IVM) and moxidectin (MOX), i.e. the major anthelmintic molecules used in current practice against cyathostomins affecting horses. A total of 102 yards and 1704 horses was studied in three countries: 60 yards and 988 horses from Italy, 22 and 396 from the UK, 20 and 320 from Germany. The survey consisted of Faecal Egg Count Reduction Tests (FECRTs) with a faecal egg count reduction (FECR) categorization of (I) resistance present if FECR <90% and the lower 95% confidenc...
Kaplan RM, Klei TR, Lyons ET, Lester G, Courtney CH, French DD, Tolliver SC, Vidyashankar AN, Zhao Y.To determine prevalence of anthelmintic resistance in cyathostome nematodes of horses in the southern United States. Methods: Cross-sectional study. Methods: 786 horses on 44 farms and stables in Georgia, South Carolina, Florida, Kentucky, and Louisiana. Methods: Fecal egg count (FEC) reduction tests were performed on 44 large farms and stables. Horses on each farm were treated with an oral paste formulation of fenbendazole, oxibendazole, pyrantel pamoate, or ivermectin at recommended label dosages. A mixed linear model was fitted to the percentage reduction in FEC, accounting for differences ...
Clark A, Sallé G, Ballan V, Reigner F, Meynadier A, Cortet J, Koch C, Riou M, Blanchard A, Mach N.Gastrointestinal strongyles are a major threat to horses' health and welfare. Given that strongyles inhabit the same niche as the gut microbiota, they may interact with each other. These beneficial or detrimental interactions are unknown in horses and could partly explain contrasted susceptibility to infection between individuals. To address these questions, an experimental pasture trial with 20 worm-free female Welsh ponies (10 susceptible (S) and 10 resistant (R) to parasite infection) was implemented for 5 months. Fecal egg counts (FEC), hematological and biochemical data, body weight and g...
Debeffe L, McLoughlin PD, Medill SA, Stewart K, Andres D, Shury T, Wagner B, Jenkins E, Gilleard JS, Poissant J.In wild and domestic animals, gastrointestinal parasites can have significant impacts on host development, condition, health, reproduction and longevity. Improving our understanding of the causes and consequences of individual-level variation in parasite load is therefore of prime interest. Here we investigated the relationship between strongyle fecal egg count (FEC) and body condition in a unique, naturalized population of horses that has never been exposed to anthelmintic drugs (Sable Island, Nova Scotia, Canada). We first quantified variation in FEC and condition for 447 individuals accordi...
Poissant J, Gavriliuc S, Bellaw J, Redman EM, Avramenko RW, Robinson D, Workentine ML, Shury TK, Jenkins EJ, McLoughlin PD, Nielsen MK, Gilleard JS.Horses are ubiquitously infected by a diversity of gastro-intestinal parasitic helminths. Of particular importance are nematodes of the family Strongylidae, which can significantly impact horse health and performance. However, knowledge about equine strongyles remains limited due to our inability to identify most species non-invasively using traditional morphological techniques. We developed a new internal transcribed spacer 2 (ITS2) DNA metabarcoding 'nemabiome' assay to characterise mixed strongyle infections in horses and assessed its performance by applying it to pools of infective larvae ...
Slusarewicz P, Pagano S, Mills C, Popa G, Chow KM, Mendenhall M, Rodgers DW, Nielsen MK.Intestinal parasites are a concern in veterinary medicine worldwide and for human health in the developing world. Infections are identified by microscopic visualisation of parasite eggs in faeces, which is time-consuming, requires technical expertise and is impractical for use on-site. For these reasons, recommendations for parasite surveillance are not widely adopted and parasite control is based on administration of rote prophylactic treatments with anthelmintic drugs. This approach is known to promote anthelmintic resistance, so there is a pronounced need for a convenient egg counting assay...
Wood EL, Matthews JB, Stephenson S, Slote M, Nussey DH.Cyathostomins are the most prevalent equine intestinal parasites and resistance has been reported in these nematodes against all 3 licensed anthelmintic classes. Strategies need to be developed that are less dependent upon drugs and more reliant on management-based control. To develop these we need to understand natural transmission patterns better. Here, we analysed longitudinal fecal egg count (FEC) data from 5 pony populations used for conservation purposes. We tested how egg excretion varied amongst populations and individuals, and how this was affected by age and climate. There was eviden...
Nielsen MK, Vidyashankar AN, Andersen UV, Delisi K, Pilegaard K, Kaplan RM.Fecal analyses are becoming increasingly important for equine establishments as a means of parasite surveillance and detection of anthelmintic resistance. Although several studies have evaluated various egg counting techniques, little is known about the quantitative effects of pre-analytic factors such as collection and storage of fecal samples. This study evaluated the effects of storage temperature, storage time and airtight versus open-air storage on fecal egg counts. The experimental protocols were replicated in two study locations: Copenhagen, Denmark and Athens, Georgia, USA. In both loc...
Nielsen MK, Vidyashankar AN, Olsen SN, Monrad J, Thamsborg SM.Nematodes belonging to the order Strongylida are ubiquitous in grazing horses, and the large strongyle Strongylus vulgaris is considered the most pathogenic. This parasite was originally described widely prevalent in equine establishments, but decades of frequent anthelmintic treatment appears to have reduced the prevalence dramatically. Increasing levels of anthelmintic resistance in cyathostomin parasites have led to implementation of selective therapy to reduce further development of resistance. It has been hypothesized that S. vulgaris could reoccur under these less intensive treatment cir...
Nielsen MK, Reinemeyer CR, Donecker JM, Leathwick DM, Marchiondo AA, Kaplan RM.Anthelmintic resistance is becoming increasingly prevalent among equine nematode parasites. The first reports documenting resistance were published in the 1960s, just a short time after introduction of the first modern anthelmintics phenothiazine and thiabendazole. Several factors are known to influence development of resistance, but evidence specific to equine parasites is limited. Most current knowledge and applications have been extrapolated from research with trichostrongylid parasites of sheep. The number of cyathostomin species co-infecting horses adds to the complexity of investigating ...
Relf VE, Lester HE, Morgan ER, Hodgkinson JE, Matthews JB.Anthelmintic drugs have been applied indiscriminately to control horse nematodes for over 40 years. We undertook a comprehensive study to investigate efficacy of the four available broad-spectrum anthelmintic drugs on 16 Thoroughbred stud farms using the faecal egg count reduction test. Efficacy against strongyles was determined by calculating the percentage of reduction in faecal egg count between the group mean at Day 0 and Days 14-17 post-treatment and the 95% lower confidence intervals estimated by non-parametric bootstrapping. Individual strongyle faecal egg count reduction tests (n=429) ...
Saeed MA, Beveridge I, Abbas G, Beasley A, Bauquier J, Wilkes E, Jacobson C, Hughes KJ, El-Hage C, O'Handley R, Hurley J, Cudmore L, Carrigan P....Equine gastrointestinal nematodes (GINs) have been the subject of intermittent studies in Australia over the past few decades. However, comprehensive information on the epidemiology of equine GINs, the efficacy of available anthelmintic drugs and the prevalence of anthelmintic resistance (AR) in Australasia is lacking. Herein, we have systematically reviewed existing knowledge on the horse GINs recorded in Australia, and main aspects of their pathogeneses, epidemiology, diagnoses, treatment and control. Methods: Six electronic databases were searched for publications on GINs of Australian hors...
Rehbein S, Visser M, Winter R.Prevalence and intensity of gastrointestinal parasites were studied through a longitudinal survey in 400 horses over a 17-month period in an abattoir in Germany. Three hundred and ten horses (77.5 %) were demonstrated harbouring endoparasites either by direct recovery of parasites from the digestive tract and/or in terms of faecal egg counts (strongyles). The following parasites were found (percentage prevalence, range of counts): Gasterophilus intestinalis larvae (2.25 %, 1-154), Gasterophilus nasalis larvae (0.25 %, 44), Trichostrongylus axei (11.0 %, 1-3,620), Habronema majus (8.0 %; 1...
Canever RJ, Braga PR, Boeckh A, Grycajuck M, Bier D, Molento MB.The increase of anthelmintic resistance in the last years in the nematode population of veterinary importance has become a major concern. The objective of the present study was to evaluate the efficacy of the main anthelmintic drugs available in the market against small strongyles of horses in Brazil. A total of 498 horses from 11 horse farms, located in the states of Paraná, São Paulo, Rio de Janeiro and Minas Gerais, in Brazil, were treated with ivermectin, moxidectin, pyrantel and fenbendazole, orally at their recommended doses. The fecal egg count reduction test (FECRT) was used to deter...
Hinney B, Wirtherle NC, Kyule M, Miethe N, Zessin KH, Clausen PH.The objective of the study was to estimate the prevalence of helminths in the horse population of the state of Brandenburg, Germany. One hundred and twenty-six horse farms in the state were selected by randomised stratified sampling. In total, 1,407 horses across all farms were examined coproscopically. The experimental unit was the horse farm: a farm was considered infected when at least one horse on the farm investigated was positive for helminth eggs. Animal details such as age, breed and sex were collected for all study horses and analysed for risk of infection. Risk was defined as horses ...
Lyons ET, Tolliver SC, Ionita M, Lewellen A, Collins SS.Field studies (n=6) were completed on evaluation of activity of ivermectin (200 microg/kg) paste formulation against small strongyles in horses (foals, yearlings, and older animals) on a farm (Farm MC) in Central Kentucky in late 2006 and during 2007. A girth tape was used to estimate body weights which were then used to calculate the proper dose rate of ivermectin. The foals, yearlings, and some of the older horses were born and raised on the farm. However, most of the older horses which were not raised on the farm had been there for several years. The horse herd was given ivermectin exclusiv...
Lind EO, Kuzmina T, Uggla A, Waller PJ, Höglund J.The objective of the study was to investigate different aspects on the efficacy of three anthelmintics on cyathostomin nematodes of Swedish horses. A faecal egg count reduction (FECR) test was performed on 26 farms. Horses were treated orally with recommended doses of ivermectin, pyrantel pamoate or fenbendazole. Faecal samples were collected on the day of deworming and 7, 14 and 21 days later. No resistance was shown against ivermectin; the FECR was constantly >99%. The effect of pyrantel was assessed as equivocal in 6 farms 14 days after treatment; the mean FECR was 99%. As many as 72% of...
Paras KL, George MM, Vidyashankar AN, Kaplan RM.Gastrointestinal nematode parasites are important pathogens of all domesticated livestock species. Fecal egg counts (FEC) are routinely used for evaluating anthelmintic efficacy and for making targeted anthelmintic treatment decisions. Numerous FEC techniques exist and vary in precision and accuracy. These performance characteristics are especially important when performing fecal egg count reduction tests (FECRT). The objective of this study was to compare the accuracy and precision of three commonly used FEC methods and determine if differences existed among livestock species. In this study, ...
Relf VE, Morgan ER, Hodgkinson JE, Matthews JB.Few studies have described the combined effect of age, gender, management and control programmes on helminth prevalence and egg shedding in grazing equines. Here, fecal samples collected from 1221 Thoroughbred horses, residing at 22 studs in the UK, were analysed. The distribution of strongyle eggs amongst individuals in relation to age, gender and management practices was investigated. Fecal worm egg counts (FWECs), described as the number of eggs per gramme (epg) of feces, were determined using a modification of the salt flotation method. The FWEC prevalence (mean%) of strongyles, Parascaris...
Bellaw JL, Krebs K, Reinemeyer CR, Norris JK, Scare JA, Pagano S, Nielsen MK.Cyathostomins are ubiquitous in grazing horses across the world, and anthelmintic resistance has been reported with increasing levels over past decades. The aims of the present study were (i) to investigate the efficacy against encysted larval stages of moxidectin (0.4 mg/kg) and fenbendazole (10 mg/kg daily for five consecutive days) and compare these regimens at 2 and 5 weeks post-treatment, (ii) to investigate individual cyathostomin species associated with shortened egg reappearance periods, and (iii) to document species exhibiting decreased susceptibility to the evaluated compounds....
Nielsen MK, Haaning N, Olsen SN.Knowledge of horses that shed the same number of strongyle eggs over time can lead to the optimization of parasite control strategies. This study evaluated shedding of strongyle eggs in 424 horses on 10 farms when a selective anthelmintic treatment regime was used over a 3-year period. Faecal egg counts were performed twice yearly, and horses exceeding 200 eggs per gram (EPG) of faeces were treated. The results are presented as probabilities of the egg count outcome, when two previous egg counts are known. A horse with no strongyle eggs detected in the two previous faecal examinations had an 8...
Scare JA, Slusarewicz P, Noel ML, Wielgus KM, Nielsen MK.Fecal egg counts are emphasized for guiding equine helminth parasite control regimens due to the rise of anthelmintic resistance. This, however, poses further challenges, since egg counting results are prone to issues such as operator dependency, method variability, equipment requirements, and time commitment. The use of image analysis software for performing fecal egg counts is promoted in recent studies to reduce the operator dependency associated with manual counts. In an attempt to remove operator dependency associated with current methods, we developed a diagnostic system that utilizes a ...
Peachey LE, Molena RA, Jenkins TP, Di Cesare A, Traversa D, Hodgkinson JE, Cantacessi C.A growing body of evidence, particularly in humans and rodents, supports the existence of a complex network of interactions occurring between gastrointestinal (GI) helminth parasites and the gut commensal bacteria, with substantial effects on both host immunity and metabolic potential. However, little is known of the fundamental biology of such interactions in other animal species; nonetheless, given the considerable economic losses associated with GI parasites, particularly in livestock and equines, as well as the global threat of emerging anthelmintic resistance, further explorations of the ...
