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.
Sallé G, Cortet J, Bois I, Dubès C, Guyot-Sionest Q, Larrieu C, Landrin V, Majorel G, Wittreck S, Woringer E, Couroucé A, Guillot J, Jacquiet P....Intestinal strongyles are the most problematic endoparasites of equids as a result of their wide distribution and the spread of resistant isolates throughout the world. While abundant literature can be found on the extent of anthelmintic resistance across continents, empirical knowledge about associated risk factors is missing. This study brought together results from anthelmintic efficacy testing and risk factor analysis to provide evidence-based guidelines in the field. It involved 688 horses from 39 French horse farms and riding schools to both estimate Faecal Egg Count Reduction (FECR) aft...
Miller FL, Bellaw JL, Lyons ET, Nielsen MK.Strongyloides westeri is a threadworm parasite found in the small intestine mainly in foals at up to about 4 months of age. This parasite is associated with small intestinal enteritis and diarrhea as well as skin irritation and a clinical syndrome called "frenzied behavior" due to percutaneous invasion. The aim of this study was to investigate S. westeri parasite burdens in age groups older than the initial lactogenic transmission phase. Secondary aims were to examine the impact of host age and gender on worm burden and egg output in naturally infected foals. Thirteen foals were enrolled in th...
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....
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 ...
Dias de Castro LL, Abrahão CLH, Buzatti A, Molento MB, Bastianetto E, Rodrigues DS, Lopes LB, Silva MX, de Freitas MG, Conde MH, Borges FA.The aim of this study was to compare two fecal egg count (FEC) techniques; McMaster (McM) and Mini-FLOTAC (mF), for the detection of cattle and horse gastrointestinal nematode eggs, in different locations. Experiment 1: feces were collected from 16 cattle and FEC was performed individually, using mF with the sensitivity of 5 eggs per gram of feces (EPG) and McM with a sensitivity of 50 EPG at Empresa de Pesquisa Agropecuária de Minas Gerais - EPAMIG and the Laboratory of Parasitic Diseases of the University of Parana - LDP/UFPR. Experiment 2: Fecal samples from 30 horses were analyzed with mF...
Stancampiano L, Usai F, Marigo A, Rinnovati R.Strongyle infections have been traditionally regarded as a possible cause of colic in horses. Aim of the study was the comparison of parasitological status between subjects with or without colic syndrome, with particular attention to small strongyle infections. Coprological analyses were performed on 86 horses: 43 with colic and 43 controls. Strongyle eggs were found in 34/86 horses (prevalence 39.5%), the mean number of strongyles eggs per gram of faeces (EPG) was 145.34 (standard deviation 398.28). All those 34 positive animals had small strongyles infections. Negative binomial multiple regr...
Tomczuk K, Grzybek M, Szczepaniak K, Studzińska M, Demkowska-Kutrzepa M, Roczeń-Karczmarz M, Abbass ZA, Kostro K, Junkuszew A.Equine Anoplocephalosis constitute a significant problem in horses worldwide. The aim of this study was to analyse intrinsic (host age and sex) and extrinsic (management type, pasture type and moisture) factors that influence the prevalence and FEC of A. perfoliata infections. Faecal samples were collected from 994 horses managed in studs or individually between 2012 and 2014. The Sedimentation-flotation method was applied for coproscopic analysis, and faecal egg counts were calculated. The overall prevalence was 25.1% (21.4-29.0) with the highest prevalence (36.1% [28.1-44.8]) found in horses...
Beasley AM, Coleman GT, Kotze AC.The use of macrocyclic lactone drugs for control of equine cyathostomins is threatened by increasing levels of resistance. Detection of changes in drug sensitivity is important for effective and sustainable management of cyathostomins, however, at present such detection relies on the use of the faecal egg count reduction test, which is known to be an insensitive method. The present study therefore aimed to examine the use of a 96-well plate larval migration inhibition test for detection of resistance to macrocyclic lactone drugs in cyathostomins. We optimised conditions for migration of larvae...
Knubben-Schweizer G, Pfister K.Anthelmintic resistance of gastrointestinal nematodes in small ruminants, but also in cattle and horses, is now found worldwide. The reason for increasing anthelmintic resistance is, in particular, the extensive use of all the anthelmintic agents available on the market. A non-targeted use leads to the selection of naturally occurring resistance genes within parasite populations. The most practical method for evaluating the efficacy of an anthelmintic is the fecal egg-count reduction test. To reduce the rate of anthelmintic resistance development, the available active substances must be applie...
Zak A, Siwinska N, Slowikowska M, Borowicz H, Kubiak K, Hildebrand J, Popiolek M, Niedzwiedz A.There are no available studies describing the possible resistance of strongyles to ivermectin in horses in Poland. One hundred seventy three horses from nine stud farms from South-Western Poland were studied. The effectiveness of ivermectin was studied on the 14th day after ivermectin administration using the fecal egg count reduction test, and a long-term observation of the egg reappearance period was carried out. The fecal study was carried out using a modified McMaster method, which typically detects 20 eggs per gram of stool. The results were subjected to statistical analysis that enabled ...
Salas-Romero J, Gómez-Cabrera KA, Aguilera-Valle LA, Bertot JA, Salas JE, Arenal A, Nielsen MK.Increasing levels of anthelmintic resistance observed in equine cyathostomin parasites have led to recommendations of selective anthelmintic treatment strategies to lower the selection pressure favoring resistant populations. This principle is based on determining strongyle fecal egg counts from all herd members, and treating those exceeding a predetermined treatment cutoff. However, epidemiological information is lacking from horses kept under tropical conditions, where parasite burdens may be of a different composition and magnitude compared to those of horses kept under temperate climate co...
Alanazi AD, Mukbel RM, Alyousif MS, AlShehri ZS, Alanazi IO, Al-Mohammed HI.In the last decade, Parascaris spp. resistance to anthelmintics has been recorded in many countries. In Saudi Arabia, there are limited data available on Parascaris spp. resistance to anthelmintics. Objective: To determine the current status of ivermectin, abamectin and praziquantel combined, and fenbendazole resistance to Parascaris spp. in horses in Saudi Arabia. Methods: Three hundred and forty-one foals from eleven different farms were examined by faecal egg count (FEC). The foals were all Arab horses aged 17.2 ± 4.5 (SD) months. Ivermectin (n = 46 foals), abamectin and praziquantel combi...
Collas C, Sallé G, Dumont B, Cabaret J, Cortet J, Martin-Rosset W, Wimel L, Fleurance G.The spread of anthelmintic resistance in equine strongyle nematodes has become a major problem, advocating for the development of alternative control for strongyles. Our study consisted of both in vivo and in vitro experiments. We investigate for the first time the efficacy of a short-term consumption of tannin-rich sainfoin (Onobrychis viciifolia) or extra proteins in naturally infected horses. We used 30 horses allocated into three groups of 10 individuals that received for 18 days either (i) a tannin-rich diet with 70% DM sainfoin pellets (Sd), (ii) a protein-rich diet with 52% DM Italian r...
Rose Vineer H, Vande Velde F, Bull K, Claerebout E, Morgan ER.Gastrointestinal nematodes present a major threat to the health and welfare of equids worldwide. Anthelmintic resistance (AR) is increasingly reported and challenges effective control in horses and ponies in many regions. The use of faecal worm egg counts (FECs) to support targeted treatment (FEC-TT) and targeted selective treatment (FEC-TST) has been promoted as an effective deworming strategy that may prolong the useful life of anthelmintics and reduce the costs associated with parasite control. However, treatment applied at set intervals or on pre-determined dates remains common. A structur...
Beasley AM, Kotze AC, Allen K, Coleman GT.The macrocyclic lactone (ML) drugs are central to the control of equine strongyles but recent international reports raise concerns about reduced efficacy of these drugs against cyathostomins. The objectives of the present study were firstly, to evaluate the efficacy of ML drugs against cyathostomins on a cross-section of Australian horse farms, and secondly, to determine the egg reappearance period (ERP) following treatment of horses with MLs. A total of 419 horses on 43 properties were treated orally with ivermectin, abamectin or moxidectin, at recommended dose rates and drug efficacy was det...
Lyons ET, Bellaw JL, Dorton AR, Tolliver SC.Field tests were performed on Thoroughbred yearlings (n=143), evaluating efficacy of moxidectin (MOX) against ascarids and strongyles and the efficacy of an ivermectin (IVM)-praziquantel (PRAZ) combination against those nematodes and tapeworms on a farm in Central Kentucky. The study was started on March 1, 2016 and completed on August 23, 2016. Fecal samples were collected from yearlings every two weeks for counts of ascarid and strongyle eggs per gram of feces (EPGs) and for determining the presence of tapeworm eggs. MOX was given to 88 yearlings on March 1; 55 yearlings were nontreated cont...
Wilkes E, McConaghy FF, Thompson RL, Dawson K, Sangster NC, Hughes KJ.This study was performed to investigate the efficacy of a morantel-abamectin combination for the treatment of macrocyclic lactone (ML)-resistant Parascaris spp. infections in foals. Methods: Foals on five properties with a Parascaris faecal egg count (FEC) > 50 eggs per gram were used to estimate the FEC reduction (FECR) and efficacy of the anthelmintic combination. Conclusions: On all properties, resistance to ivermectin and abamectin was present and the Parascaris FECR in foals administered the morantel-abamectin combination was > 99%, indicating that this combination effective...
Tzelos T, Barbeito JS, Nielsen MK, Morgan ER, Hodgkinson JE, Matthews JB.Parasitic nematodes, particularly cyathostomins, are ubiquitous in grazing horses world-wide. Considerable burdens of cyathostomin larvae can encyst in the large intestinal wall. The most recommended treatment against these pathogenic stages is moxidectin. Information is required on how effective moxidectin is against cyathostomin populations in different regions. The objectives here were to determine the efficacy of moxidectin treatment and estimate the strongyle egg reappearance period (ERP) after treatment in several equine populations, to confirm the type of strongyle nematodes present and...
Seyoum Z, Zewdu A, Dagnachew S, Bogale B.A study was conducted from November 2015 to April 2016 to determine fenbendazole and ivermectin resistance status of intestinal nematodes of cart horses in Gondar, Northwest Ethiopia. Forty-five strongyle infected animals were used for this study. The animals were randomly allocated into three groups (15 horses per group). Group I was treated with fenbendazole and Group II with ivermectin and Group III was left untreated. Faecal samples were collected from each cart horse before and after treatment. Accordingly, the reduction in the mean fecal egg count at fourteen days of treatment for iverme...
Rosanowski SM, Bolwell CF, Scott I, Sells PD, Rogers CW.Against a global background of increasing anthelmintic resistance in parasites and a domestic over-reliance on anthelmintics to control gastrointestinal parasites, little is currently known about the resistance status of equine parasites in New Zealand. The objective of the study was to investigate the efficacy of ivermectin in yearling Thoroughbreds. Data were collected from six stud farms from November 2014 to January 2015. Yearlings were selected based on not being treated with anthelmintics for a minimum of six weeks previously and on having a preliminary screening strongyle faecal egg cou...
The goal of the current study was to evaluate the comparative efficacy of ivermectin (IVM) against small strongyles (cyathostomins) following its oral and intramuscular (IM) administration, in naturally parasitized horses. The parasitological data were complemented with the assessment of the plasma disposition kinetics of IVM. The trial included two different experiments. In experiment I, 40 horses naturally infected with small strongyles were randomly allocated into four experimental groups (n=10) and treated with IVM (0.2mg/kg) as follows: IVM oral paste, animals were orally treated with Eqv...
Salas-Romero J, Gomez-Cabrera K, Molento MB, Lyons ET, Delgado A, González L, Arenal A, Nielsen MK.Equine cyathostomin parasites are ubiquitous in grazing horses and have been shown to cause severe inflammatory disease in the large intestine of horses. Decades of intensive anthelmintic therapy have led to widespread anthelmintic resistance in cyathostomins across the world. In Cuba, no anthelmintic products are formulated and sold for equine usage and little is known about anthelmintic efficacy of ruminant and swine formulations used. A strongyle fecal egg count reduction test was used to assess the efficacy of a liquid formulation of ivermectin labelled for use in swine, ruminants and carn...
Ishii JB, Arenal A, Felix A, Yoshitani U, Beech R, Molento MB.Anthelmintic resistance is a serious problem for the control of equine gastrointestinal nematodes. In the present survey, 173 third stage larvae of cyathostomins were investigated from three different locations for the presence of the resistant genotype at codon 167 of the beta-tubulin gene, as this is the most prevalent mutation. The larvae from the state of Parana (n=67), Sao Paulo (n=54) and Santa Catarina (n=52), showed 61.2; 31.5 and 38.5% of the heterozygous resistant genotype - TTC/TAC, respectively. An unpublished mutation at codon 172 that results in a serine (S) to threonine (T) subs...
Daniels SP, Proudman CJ.This study reports ivermectin and moxidectin egg reappearance periods (ERP) from UK horses with persistently positive faecal egg counts (FEC), defined as positive FEC within the ERP of an anthelmintic post-treatment, or with FECs that remained positive after the normal ERP post-anthelmintic treatment. A selected population of UK pleasure horses deemed at high risk of strongyle infection was studied. The earliest ERP recorded after ivermectin or moxidectin, using first positive FEC, was 5 weeks. From 16 premises where moxidectin was used, five had ERP ≥12 weeks using two further metrics. For ...
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 ...
Easton S, Pinchbeck GL, Tzelos T, Bartley DJ, Hotchkiss E, Hodgkinson JE, Matthews JB.Helminths are common pathogens of equids and anthelmintic resistance is a major issue in cyathostomin species and Parascaris equorum. At the heart of mitigating the impact of increasing anthelmintic resistance levels, is the responsible dissemination and use of these medicines following best practice principles. There is a paucity of information on interactions between horse owners and anthelmintic prescribers and how this shapes control. Here, a study was undertaken to determine opinions and experiences of horse owners as they relate to anthelmintics purchase and implementation of best practi...
Wilkes EJA, Cowling A, Woodgate RG, Hughes KJ.Faecal egg counts (FEC) are used widely for monitoring of parasite infection in animals, treatment decision-making and estimation of anthelmintic efficacy. When a single count or sample mean is used as a point estimate of the expectation of the egg distribution over some time interval, the variability in the egg density is not accounted for. Although variability, including quantifying sources, of egg count data has been described, the spatiotemporal distribution of nematode eggs in faeces is not well understood. We believe that statistical inference about the mean egg count for treatment decis...
Saes IL, Vera JHS, Fachiolli DF, Yamada PH, Dellaqua JVT, Saes RL, Amarante AFT, Soutello RVG.The aim of this study was to determine the time required by different anthelmintic agents to reduce strongyle egg shedding in horses. Fifty horses were divided into five homogenous groups based on faecal egg counts (FECs). Treatment groups received either ivermectin; moxidectin; fenbendazole; piperazine; or no treatment (control group). Faecal examinations were performed 4, 8, 12, 18, 24, 36 and 48h after the anthelmintic treatment. After this period, faecal samples were taken every 24h over the next 12days and finally on alternate days (48-h intervals) for another 14days until the end of the ...
Moudgil AD, Prashar A, Moudgil P, Sharma A, Sharma M.The small strongyles also called as cyathostomes, cyathostomins or trichonemes, affect the health status of equines, leading to morbidity and mortality in heavily infested individuals. The present study was carried out with the aim to identify the cause of colic in a mule of Palam valley, Himachal Pradesh, India. The detailed faecal sample examination revealed heavy intensity of strongyle eggs with an egg per gram value of 2300. The collected faecal sample also exhibited presence of adult worms. The morphological observations after clearing the retrieved parasites revealed the presence of adul...
Hernández JÁ, Arroyo FL, Suárez J, Cazapal-Monteiro CF, Romasanta Á, López-Arellano ME, Pedreira J, de Carvalho LMM, Sánchez-Andrade R....The usefulness of pellets industrially manufactured with spores of parasiticide fungi as a contribution to integrated nematode control was assessed in grazing horses throughout sixteen months. Two groups of 7 Pura Raza Galega autochthonous horses (G-T and G-P) were dewormed pour-on (1mg Ivermectin/kg bw) at the beginning of the trial, and other group (G-C) remained untreated. The G-P was provided daily with commercial pellets to which was added a mixture of fungal spores during the industrial manufacturing (2×10 spores of Mucor circinelloides and same dose of Duddingtonia flagrans/kg), and G-...
Slocombe JO.Aims of this study with 13 equids naturally infected with Anoplocephala perfoliata were to document (i) a critical test with a period of 48 h from treatment to necropsy to assess the efficacy of an anthelmintic against the tapeworm, (ii) the efficacy of pyrantel pamoate oral paste at 13.2 mg pyrantel base/kg body weight, and (iii) the time after treatment when fecal egg counts would best estimate the tapeworm's prevalence in a herd. Feces passed in successive 12-h periods after treatment were examined for tapeworms. At necropsy, tapeworms in equids were identified as attached to the mucosa or ...
Boelow H, Krücken J, Thomas E, Mirams G, von Samson-Himmelstjerna G.Due to high prevalence of anthelmintic resistance in equine helminths, selective treatment is increasingly promoted and in some countries a positive infection diagnosis is mandatory before treatment. Selective treatment is typically recommended when the number of worm eggs per gram faeces (epg) exceeds a particular threshold. In the present study we compared the semi-quantitative sedimentation/flotation method with the quantitative methods Mini-FLOTAC and FECPAK in terms of precision, sensitivity, inter-rater reliability and correlation of worm egg counts to improve the choice of optimal diagn...
Neuhaus S, Bruendler P, Frey CF, Gottstein B, Doherr MG, Gerber V.Equine recurrent airway obstruction (RAO) shares many characteristics with human asthma. In humans, an inverse relationship between susceptibility to asthma and resistance to parasites is suspected. Objective: Members of a high-incidence RAO half-sibling family (F) shed fewer strongylid eggs compared with RAO-unaffected pasture mates (PM) and that RAO-affected horses shed fewer eggs than RAO-unaffected half-siblings. Methods: Seventy-three F and 73 unrelated, age matched PM. Methods: Cases and controls kept under the same management and deworming regime were examined. Each individual was class...
Tyson F, Dalesman S, Brophy PM, Morphew RM.Faecal egg counts (FECs) are the standard method of diagnosing the level of parasitic helminth egg shedding in horses and other grazing animals. Testing before treatment is an important factor in slowing the appearance of anthelmintic resistance in nematode parasites. The FECPAK, optimised for livestock, is reported to allow owners to perform FECs on their own animals without the need for a separate microscope or any specialist knowledge by tapping into remote expertise. However, the performance of the FECPAK has yet to be assessed for equids. Therefore, a comparison of the FECPAK (G2) method ...
McFarlane D, Hale GM, Johnson EM, Maxwell LK.To determine effects of pituitary pars intermedia dysfunction (Cushing's disease) and age on fecal egg count and time to egg reappearance after anthelmintic treatment in horses residing in similar environments. Methods: Cross-sectional study. Methods: 29 healthy horses (4 to 35 years old) and 13 horses with PPID (13 to 33 years old). Methods: Fecal egg counts were performed by use of a modified Wisconsin flotation method at 2-week intervals before and after ivermectin treatment. Results: Horses with PPID had higher fecal egg counts before and 8, 10, and 12 weeks after ivermectin treatment, com...
Smith HJ.Five of seven ponies whose strongyle worm burdens had previously been removed or markedly reduced by repeated thiabendazole treatments were reinfected with doses ranging from 100,000 to 500,000 small strongyle infective larvae. Reinfection of ponies resulted in the development of clinical signs characterized by abnormal feces, marked loss of weight and delayed shedding of winter hair coats. An abrupt increase in circulating eosinophils occurred during the first three weeks following reinfection. Patent infections developed in all ponies with worm eggs appearing in the feces from 12 to 15 weeks...
Matthee S, Dreyer FH, Hoffmann WA, van Niekerk FE.Fifty-one per cent of 110 questionnaires, designed for obtaining information on helminth control practices and management on Thoroughbred stud farms in South Africa, were completed by farmers during 2000. The number of horses per farm included in the questionnaire survey ranged from 15 to 410. Foals, yearlings and adult horses were treated with anthelmintics at a mean of 7.3 +/- 3.0, 6.6 +/- 2.7 and 5.3 +/- 2.3 times per year, respectively. An average of 3.4 different drugs were used annually, with ivermectin being used bymost farmers during 1997-2000. On 43% of farms the weights of horses wer...
Borgsteede FH, Boersma JH, Gaasenbeek CP, van der Burg WP.The reappearance of nematode eggs in faeces after ivermectin treatment was studied in 104 horses on 10 farms during the stabling period. Faecal samples were taken at weekly intervals. Sampling was discontinued when the mean egg output per farm was > 10% of the pre-treatment egg output. This point was reached after 63 days, when the mean output of eggs had decreased to 70.3%. Before treatment, 95.9% of the cultured larvae were of the cyathostome type, the others belonged to Gyalocephalus capitatus, Strongylus vulgaris, S. edentatus, Oesophagodontus/Poteriostomum spp., Triodontophorus spp. an...
Scare JA, Lyons ET, Wielgus KM, Nielsen MK.Equine cyathostomin are pervasive gastrointestinal parasites with wide-spread resistance to the benzimidazole and tetrahydropyrimidine drug classes worldwide. Combination deworming has been proposed as a more sustainable parasite control strategy. Simulation studies have found combination deworming to be effective in controlling drug resistant ovine trichostrongylid parasites. One equine study demonstrated an additive effect of a combination of oxibendazole and pyrantel pamoate against cyathostomins. However, this is the only equine study evaluating combination therapy, and the effects of repe...
Kornaś S, Sallé G, Skalska M, David I, Ricard A, Cabaret J.Equine internal parasites, mostly cyathostomins, affect both horse welfare and performance. The appearance of anthelmintic-resistant parasites creates a pressing need for optimising drenching schemes. This optimization may be achieved by identifying genetic markers associated with host susceptibility to infection and then to drench carriers of these markers. The aim of our study was to characterise the genetics of horse resistance to strongyle infection by estimating heritability of this trait in an Arabian pure blood population. A population of 789 Arabian pure blood horses from the Michałó...
von Samson-Himmelstjerna G, von Witzendorff C, Sievers G, Schnieder T.A survey on benzimidazole (BZ) resistance in small strongyles was performed on three farms in the tenth region in Chile. Samples from a total of 100 horses were tested using the faecal egg count reduction test (FECRT), the egg hatch assay (EHA) and an allele-specific PCR for the detection of beta-tubulin isotype 1 genes coding for phenylalanine (phe) or tyrosine (tyr) at codon 200. In the past, BZ-type drugs have been used within anthelmintic campaigns on all the three farms. This has predictably led to a high degree of BZ resistance at the Valdivia and Riñihue farms and to a lesser degree at...
Steuer AE, Anderson HP, Shepherd T, Clark M, Scare JA, Gravatte HS, Nielsen MK.Horses are host to a plethora of parasites. Knowledge of the seasonality of parasite egg shedding and transmission is important for constructing parasite control programs. However, studies describing these patterns are sparse, and have largely been conducted only in the United Kingdom. This study evaluated strongylid egg shedding patterns and transmission dynamics of Strongylus vulgaris in naturally infected and untreated mares and foals through one calendar year in Kentucky, USA. The study also investigated the existence of a peri-parturient rise (PPR) in strongylid egg counts in foaling mare...
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...
Tydén E, Dahlberg J, Karlberg O, Höglund J.The development of anthelmintic resistance (AR) to macrocyclic lactones in the equine roundworm Parascaris equorum has resulted in benzimidazoles now being the most widely used substance to control Parascaris infections. However, over-reliance on one drug class is a risk factor for the development of AR. Consequently, benzimidazole resistance is widespread in several veterinary parasites, where it is associated with single nucleotide polymorphisms (SNPs) in drug targets encoded by the β-tubulin genes. The importance of these SNPs varies between different parasitic nematodes, but it has been h...
Rose Vineer H, Vande Velde F, Bull K, Claerebout E, Morgan ER.Gastrointestinal nematodes present a major threat to the health and welfare of equids worldwide. Anthelmintic resistance (AR) is increasingly reported and challenges effective control in horses and ponies in many regions. The use of faecal worm egg counts (FECs) to support targeted treatment (FEC-TT) and targeted selective treatment (FEC-TST) has been promoted as an effective deworming strategy that may prolong the useful life of anthelmintics and reduce the costs associated with parasite control. However, treatment applied at set intervals or on pre-determined dates remains common. A structur...
Fischer JK, Hinney B, Denwood MJ, Traversa D, von Samson-Himmelstjerna G, Clausen PH.Cyathostomins are currently the most common internal parasites of horses. With the intensive use of anthelmintic drugs over the past decades, resistance of cyathostomins to anthelmintics is becoming a growing problem in many countries. The aim of this study was to assess the current situation on horse farms in the German federal state of Brandenburg. A pre-selected population of horses from 24 premises that had shown a prevalence of cyathostomins higher than the average in a previous study was examined for anthelmintic efficacy. Faecal egg count reduction tests (FECRTs) were performed for iver...
Scare JA, Leathwick DM, Sauermann CW, Lyons ET, Steuer AE, Jones BA, Clark M, Nielsen MK.An alternative control regimen for drug-resistant parasites is combination deworming, where two drugs with different modes of action are administered simultaneously to target the same parasite. Few studies have investigated this in equine cyathostomins. We previously reported that an oxibendazole (OBZ) and pyrantel pamoate (PYR) combination was not sustainable against a cyathostomin population with high levels of OBZ and PYR resistance. This study consisted of a field study and two computer simulations to evaluate the efficacy of a moxidectin-oxibendazole (MOX-OBZ) combination against the same...
Nilsson O, Lindholm A, Christensson D.A field evaluation of anthelmintics in 336 horses on 37 farms was conducted between February and May 1986 in Sweden. The herds, each comprising at least eight horses, had histories of grazing on permanent pastures and receiving regular treatments against parasites at least three times a year. Small strongyles were refractory to (pro)-benzimidazole drugs in all but one of 23 herds examined. There was an average reduction in egg output of approximately 60%, and approximately 30% of 205 horses examined were shedding less than 100 eggs g-1 7 days after treatment. There was great between-herd varia...
Wilkes E, McConaghy FF, Thompson RL, Dawson K, Sangster NC, Hughes KJ.This study was performed to investigate the efficacy of a morantel-abamectin combination for the treatment of macrocyclic lactone (ML)-resistant Parascaris spp. infections in foals. Methods: Foals on five properties with a Parascaris faecal egg count (FEC) > 50 eggs per gram were used to estimate the FEC reduction (FECR) and efficacy of the anthelmintic combination. Conclusions: On all properties, resistance to ivermectin and abamectin was present and the Parascaris FECR in foals administered the morantel-abamectin combination was > 99%, indicating that this combination effective...
Warnick LD.Fecal egg counts often are used for diagnosing equine strongyle infections and estimating the number of eggs shed in the feces. An individual egg count should be interpreted in view of the normal fluctuation of egg numbers in an individual horse. In this study, the daily variability of strongyle fecal egg counts from horses was investigated. The Cornell-McMaster egg-counting technique was used to estimate the eggs per gram of feces in repeated daily fecal samples from 39 horses. The variation of the daily egg counts across 4 days was greater than would be expected if a consistent number of egg...
Krecek RC, Guthrie AJ, Van Nieuwenhuizen LC, Booth LM.Little information exists concerning the presence of nematode parasites of horses in South Africa. Limited studies are available which compare the parasites in horses originating from differing management schemes. The aim of the present study was to compare the nematode parasites of 2 groups of horses which had been managed differently. Group 1, chiefly Nooitgedacht adult ponies, consisted of cycling or early pregnancy mares. They were maintained chiefly on zero grazing, given supplemental feed and treated 4 times a year with antiparasitic remedies. The horses in Group 2 were mostly Thoroughbr...
Cain JL, Foulk D, Jedrzejewski E, Stofanak H, Nielsen MK.Anthelmintic resistance in equine cyathostomin parasites is widespread. A surveillance-based parasite control program using fecal egg counts (FECs) and fecal egg count reduction tests (FECRTs) to decrease anthelmintic use and monitor treatment efficacy is recommended. The purpose of this study was to examine shifts in equine parasite control program management practices via a short course presented by the Penn State Extension, and to highlight how data collected from these programs is useful for monitoring anthelmintic efficacy on a large scale. Horse owners were enrolled after participating i...
Malsa J, Courtot É, Boisseau M, Dumont B, Gombault P, Kuzmina TA, Basiaga M, Lluch J, Annonay G, Dhorne-Pollet S, Mach N, Sutra JF, Wimel L....Alternative strategies to chemical anthelmintics are needed for the sustainable control of equine strongylids. Bioactive forages like sainfoin () could contribute to reducing drug use, with the first hints of activity against cyathostomin free-living stages observed in the past. We analysed the effect of a sainfoin-rich diet on cyathostomin population and the efficacy of oral ivermectin treatment. Two groups of 10 naturally infected horses were enrolled in a 78-day experimental trial. Following a 1-week adaptation period, they were either fed with dehydrated sainfoin pellets (70% of their die...
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...
Mercier P, Chick B, Alves-Branco F, White CR.Eighty horses were involved in a comparative, controlled, and randomised field study conducted in Australia and Brazil. This study was undertaken to address the duration of efficacy (by faecal egg count reduction) of four anthelmintic pastes and to measure the time required between treatments on horses naturally infected by gastrointestinal nematodes. The treatment interval was based on the egg reappearance period (ERP), defined as "the period after treatment when horses have reached a positive egg count equal or superior to 200 eggs per gram (epg) of faeces". Horses were ranked according to p...
Boelow H, Krücken J, von Samson-Himmelstjerna G.Gastrointestinal nematodes are ubiquitous parasites of grazing equines with Parascaris spp., and strongyles being the most relevant ones regarding the prevalence and potential disease severity. Despite their importance, epidemiological data regarding the presence and egg-shedding intensities of these parasites are scarce. Data from 1067 horse samples collected on German horse farms initially to compare diagnostic methods were used for epidemiological analyses. Due to its higher sensitivity, presence/absence data were based on a combined sedimentation/flotation technique while faecal egg counts...
The goal of the current study was to evaluate the comparative efficacy of ivermectin (IVM) against small strongyles (cyathostomins) following its oral and intramuscular (IM) administration, in naturally parasitized horses. The parasitological data were complemented with the assessment of the plasma disposition kinetics of IVM. The trial included two different experiments. In experiment I, 40 horses naturally infected with small strongyles were randomly allocated into four experimental groups (n=10) and treated with IVM (0.2mg/kg) as follows: IVM oral paste, animals were orally treated with Eqv...
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...
Larsen MM, Lendal S, Chriél M, Olsen SN, Bjørn H.A questionnaire survey regarding endoparasite control practices in Danish horse herds was carried out in 1995. The participating veterinarians and herd owners were sampled using convenience and purposive sampling. In the analysis of risk factors for development of a high endoparasitic burden (> 200 eggs per gram faeces) 903 horses were sampled and the analysis of the efficiency of a single anthelmintic treatment was based on 605 horses. The following factors had a significant effect on the endoparasitic burden: herd type, age of the horses, use of pasture rotation, anthelmintic treatment of ho...
