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.
Martins AV, Corrêa LL, Ribeiro MS, Lobão LF, Dib LV, Palmer JPS, de Moura LC, Knackfuss FB, Uchôa CMA, Molento MB, Barbosa ADS.The aims of this study were to determine the prevalence of helminths in Thoroughbred horses in Rio de Janeiro; make correlations with risk factors for these infections; and compare the efficiency of three floatation solutions applied in the quantitative Mini-FLOTAC technique. Fecal samples from 520 horses were collected from six training centers between 2019 and 2021. These were subjected to the Mini-FLOTAC technique using three solutions: NaCl (density = 1.200 g/mL), ZnSO4 (1.350 g/mL) and ZnSO4 (1.200 g/mL); and also to qualitative techniques. Information on the horses' sex and age of hors...
de Favare GM, de Almeida Cipriano I, do Carmo TA, Mena MO, Guelpa GJ, do Amarante AFT, de Soutello RVG.The indiscriminate use of drugs to control gastrointestinal helminths in horses can lead to serious consequences for the animals, which represents a growing problem for health, animal welfare and productivity. Therefore, the present study aimed to evaluate the anthelmintic efficacy of ivermectin in naturally infected horses in the western region of the state of São Paulo. From May 2021 to April 2022, 123 naturally infected adult horses in 12 equine breeding farms (7 to 14 animals per farm) were evaluated with the fecal egg count reduction test. The horses had not been treated with anthelminti...
Stoughton WB, Begin S, Outman S, Stryhn H, Yu J, Conboy G, Nielsen MK.Widespread overuse of anthelmintics has produced a growing population of intestinal parasites resistant to control measures. A paradigm shift in equine parasite control is warranted to prevent continued resistance development and maintain equine health. Small strongyles, which are ubiquitous in horses, are currently the most important intestinal parasites of adult horses. Sustainable management programs consider the variation in egg shedding by individual horses, and varied risks associated with age, use, density, climate, and environment. To develop regional recommendations for Prince Edward ...
Boisseau M, Mach N, Basiaga M, Kuzmina T, Laugier C, Sallé G.Equine strongyles encompass more than 64 species of nematode worms that are responsible for growth retardation and the death of animals. The factors underpinning variation in the structure of the equine strongyle community remain unknown. Methods: Using horse-based strongyle community data collected after horse deworming (48 horses in Poland, 197 horses in Ukraine), we regressed species richness and the Gini-Simpson index upon the horse's age, faecal egg count, sex and operation of origin. Using the Ukrainian observations, we applied a hierarchical diversity partitioning framework to estimate ...
Elghryani N, McOwan T, Mincher C, Duggan V, de Waal T.Gastrointestinal helminths are ubiquitous in horse populations across the world. Intensive anthelmintic treatments have succeeded in controlling some of the pathogenic effects of these parasites. However, the success of anthelmintic drugs has been threatened by the development of widespread resistance to those most commonly used. To develop improved control strategies, information on helminth distribution patterns is needed, which can be obtained by identifying animals regarded as high egg shedders and taking age, gender, and other risk factors into account. The aim of this study was to determ...
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...
Halvarsson P, Tydén E.Gastrointestinal nematode parasites are of major concern for horses, where Strongylus vulgaris is considered the most pathogenic among the Strongylus species. Diagnosis of S. vulgaris infections can be determined with next generation sequencing techniques, which are inherently dependent on reference sequences. The best marker for parasitic nematodes is internal transcribed spacer 2 (ITS2) and we provide the first complete ITS2 sequences from five morphologically identified S. vulgaris and additional sequences from two S. edentatus. These sequences have high similarity to already published part...
Poulsen L, Henriksson FV, Dahl M, Honoré ML, Olsen SN, Leifsson PS, Staerk-Østergaard J, Jacobsen S, Pihl TH.Horses with non-strangulating intestinal infarction (NSII) are often misdiagnosed with idiopathic peritonitis or acute colitis. Early diagnosis is essential to ensure early surgical intervention and improve survival. Clinical and laboratory data from horses admitted to the University of Copenhagen Large Animal Teaching Hospital with NSII, idiopathic peritonitis or acute colitis between 2009 and 2018 were used for univariate comparisons and a multivariable logistic regression model for prediction of NSII. Two hundred and thirty-one horses were included. A multivariable model for the prediction ...
Amer MM, Desouky AY, Helmy NM, Abdou AM, Sorour SS.Strongylid and non-strongylid nematodes are one of the most important parasites infecting equines. The traditional method to identify these nematodes is through coproscopy and fecal culture. Because of the scarcity of data published in Egypt discussing the morphometric features of infective 3 larvae of these nematodes, this study aims to provide a morphometric key for L3 of common strongylid and non-strongylid nematodes infecting Egyptian equines. For this reason, we cultured fecal samples containing GINs eggs and 3 larval stages were identified based on their morphology (i.e., shape and numbe...
Junco M, Iglesias LE, Sagüés F, Zegbi S, Guerrero I, Saumell CA.In horses, the nematodes of the Strongylidae family are the most important due to their prevalence and pathogenicity. Sanitary plans include parasite control based on chemical anthelmintics. Among these, the benzimidazole compounds have been used since the 1960s to control the nematode Strongylus vulgaris. Its inappropriate use resulted in the development of resistance in parasites with a shorter biological cycle, such as the small strongyles. Currently, the genera that make up this group show widespread resistance to all chemical treatments available in veterinary medicine, except for macrocy...
Apolinário ECF, Oliveira LLDS, Rocha RHF, Silva FVE, Santos IS, Alves CA, Dias Júnior JA, Mendes LJ, Lima WDS.The intensive use of anthelmintics has resulted in resistant parasite populations in horses. The objective of this trial was to evaluate the anthelmintic efficacies of the anthelmintics fenbendazole, ivermectin and abamectin in 24 horse farms in Northern Minas Gerais. Egg counts per gram of faeces (EPG) were performed individually in 619 animals. Animals presenting EPG counts greater than or equal to 150 were used in the tests on faecal egg count reduction (FECR), totalling 436 equines. These animals received the anthelmintics, fenbendazole, ivermectin, and abamectin. Faeces were collected 14...
Żak-Bochenek A, Bajzert J, Sambor D, Siwińska N, Szponar B, Łaczmański Ł, Żebrowska P, Czajkowska A, Karczewski M, Chełmońska-Soyta A.The defensive function of the intestinal mucosa depends both on the ability to secrete immunoglobulin A and communication with the mucus microbiome. In horses, the functioning of this system is also influenced by the presence of nematode eggs. Feces collected from healthy horses were examined to determine the fecal egg count, immunoglobulin A level (ELISA), microbiome composition (Next-Generation Sequencing, NGS, V3−V4 and V7−V9 hypervariable regions of the 16S rRNA gene analysis and short-chain fatty acid (SCFA) production ((high-performance liquid chromatography, HPLC). In the taxonomic ...
Osterman-Lind E, Hedberg Alm Y, Hassler H, Wilderoth H, Thorolfson H, Tydén E.Horses, as grazing animals, are inadvertently exposed to intestinal parasites that, if not controlled, may cause disease. However, the indiscriminate use of anthelmintic drugs has led to drug resistance, highlighting the need for pasture-management practices to reduce the level of parasitic exposure and lessen reliance on drugs. The efficacy of such methods depends both on the epidemiology of the parasites and the prevailing weather conditions. The aim of the study was to investigate the effect of faecal removal and harrowing on reducing the number of parasite larvae in herbage. Moreover, the ...
Nielsen MK, Steuer AE, Anderson HP, Gavriliuc S, Carpenter AB, Redman EM, Gilleard JS, Reinemeyer CR, Poissant J.Macrocyclic lactones have been the most widely used drugs for equine parasite control during the past four decades. Unlike ivermectin, moxidectin exhibits efficacy against encysted cyathostomin larvae, and is reported to have persistent efficacy with substantially longer egg reappearance periods. However, shortened egg reappearance periods have been reported recently for both macrocyclic lactones, and these findings have raised several questions: (i) are egg reappearance period patterns different after ivermectin or moxidectin treatment? (ii) Are shortened egg reappearance periods associated w...
Sargison N, Chambers A, Chaudhry U, Costa Júnior L, Doyle SR, Ehimiyein A, Evans M, Jennings A, Kelly R, Sargison F, Sinclair M, Zahid O.Understanding the composition of gastrointestinal nematode communities may help to mitigate or exploit parasite adaptations within their host. We have used nemabiome deep amplicon sequencing of internal transcribed spacer-2 (ITS-2) ribosomal DNA to describe the temporal and host species composition of gastrointestinal nematode communities following sampling of six Scottish ponies across 57 months. In the absence of parasite control, each horse showed seasonal trends of increases and decreases in faecal egg counts, consistent with the epidemiology of equine strongylid parasites, however, the c...
Dauparaitė E, Kupčinskas T, Varady M, Petkevičius S.Control of strongyle infections presents a global challenge for horse practitioners due to the development of anthelmintic resistance (AR), however comprehensive information on AR in Lithuania is still lacking. The aim of this study was to assess the current situation of fenbendazole (FBZ) AR in horses at stable level in Lithuania. Results: Faecal samples from 121 horses from six stables were examined using the Mini-FLOTAC method. Of these, 89 horses met the inclusion criteria that included strongyle faecal egg counts (FEC) exceeding 200 eggs per gram (EPG). Faecal egg count reduction tests (F...
Alemayehu MT, Abebe BK, Haile SM.Horses are used for a variety of purposes in Ethiopia. However, their service is hampered by a variety of health issues. Strongylosis is a parasitic infestation of the gastrointestinal tract that has a significant impact on the working ability, reproductive performance, well-being, and welfare of horses. The existence of Strongylosis in the study area is reported from clinical cases; however, its prevalence has not been well studied. Unassigned: The current study was carried out from January 2019 to July 2019, to determine the prevalence and associated risk factors of Strongyle in horses in an...
Baranova MV, Panova OA, Polukhina DN, Panova DS.Anthelmintics are used to control equine nematodes. However, helminth resistance to regularly used drugs is a well-known challenge. Among tests to assess effective control and monitor resistance, the most common is the fecal egg count reduction test (FECRT). In the absence of reliable FECRT results, the nematode egg reappearance period (ERP) is taken into account. This study aimed to examine horses from farms around the Moscow Region to assess nematode resistance through ERP after therapy. Unassigned: In the first stage, fecal samples from 280 horses were examined by the flotation method with ...
Jürgenschellert L, Krücken J, Bousquet E, Bartz J, Heyer N, Nielsen MK, von Samson-Himmelstjerna G.The infection of horses with strongylid nematodes is highly prevalent, with multi-species infections being the rule. spp. and in particular are amongst the most pathogenic strongyle equine parasites. Presumably due to regular strategic anthelmintic treatments in combination with long prepatencies, prevalence of these worms was severely reduced in past decades. In this study, 484 horses from 48 farms in Berlin/Brandenburg, Germany were sampled between May 2017 and January 2018. Mini-FLOTAC and combined sedimentation/flotation were used to analyse faecal samples and larval cultures were carrie...
Spieler N, Schnyder M.Intestinal helminth management in horses has both clinical and epidemiologic relevance, in additional association with anthelmintic resistance. The Swiss Army employs military owned riding horses and privately owned pack horses, which are brought together for service periods up to 12 weeks. We compared husbandry conditions and intestinal helminth management of both groups via questionnaire and analysed faecal samples of 53 riding horses and 130 pack horses using combined sedimentation/flotation, the McMaster method and larval cultures. Riding horses only had cyathostomin infections (prevalence...
Hedberg-Alm Y, Tydén E, Tamminen LM, Lindström L, Anlén K, Svensson M, Riihimäki M.Peritonitis in horses secondary to non-strangulating infarction (NSII) has a guarded prognosis, even after intestinal resection. In contrast, horses with idiopathic peritonitis respond well to medical treatment. Affected horses in both cases often show signs of both colic and systemic inflammation, but early diagnosis is crucial for optimal treatment and an accurate prognosis. One cause of NSII is thrombus formation secondary to Strongylus vulgaris larval migration. There has been a documented increase in S. vulgaris prevalence in Sweden since the implementation of selective anthelmintic treat...
Grimm P, Laroche N, Julliand S, Sorci G.It is increasingly difficult to control equine strongyles with synthetic drugs, as resistance is commonly observed. Here, we investigated the possible anthelmintic effect of sainfoin (), a polyphenol-rich legume, in naturally infected horses. On Day 0 (D0), 17 horses were allocated to three different homogenous groups in terms of fecal egg count (FEC): the control group (CONT) received a diet composed on a DM basis of 83% hay and 17% wheat bran, while in the sainfoin 1 (SF1) and sainfoin 2 (SF2) groups, half or all wheat bran, respectively, was replaced by dehydrated sainfoin pellets. The infe...
Nielsen MK, Littman BA, Orzech SW, Ripley NE.Equine cyathostomins are ubiquitous in grazing horses around the world and a main target in parasite control programs. Anthelmintic resistance has been reported with increasing frequency in these parasites over the past decades, and recent findings of fulminant resistance to the macrocyclic lactone class have raised severe concerns. This study aimed to evaluate ivermectin efficacy in cohorts of yearlings and mares present on four different farms in Central Kentucky. Strongylid egg counts were determined with an automated egg counting system, and the percent fecal egg count reduction (FECR) was...
Nápravníková J, Várady M, Vadlejch J.The control of strongylid infections has become challenging globally for equine practitioners due to the development of anthelmintic resistance. Comprehensive information on anthelmintic resistance in the Czech Republic, however, is still lacking. This study monitored the current efficacy of fenbendazole, pyrantel embonate, ivermectin and moxidectin. Forty-eight of 71 operations met the criteria (≥6 horses with ≥200 eggs per gram), with 969 fecal egg count reduction tests performed. Anthelmintic resistance was evaluated on an operation level based on fecal egg count reduction (FECR) and th...
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...
Gündoğ SÖ, Çelik F, Şimşek S.This study was aimed to evaluate the parasitic diseases in patients brought to Firat University Animal Hospital (FUAH) between 1972 and 2019. Patient records between 03.31.1972 and 06.02.1982 and between 04.24.2012 and 15.09.2019 in the archive of FUAH were checked. In the mentioned period, 50.17% of the patients that applied to FUAH were cattle, 18.42% were dogs, 13.04% were horses, 10.7% were sheep, 3.26% were cats, 3.18% were goats, and 1.2% were other animals (rabbit, ornamental birds, donkey, and chicken). In this period, various parasitic diseases were detected in 1.411 (3.83%) of a tota...
Scare Kenealy JA, Steuer AE.All horses are susceptible to the equine gastrointestinal parasite, Strongylus vulgaris, which is known to cause significant disease and death. The parasite undergoes development from the egg through the first (L1), second (L2) and third (L3) larval stages outside the horse. The L3 is the infective stage. The universally available technique for detection of S. vulgaris larvae is the larval culture method. This requires a 10-14 day culture period to induce development from egg to L3, followed by Baermannization and identification of the L3s to genus and/or species. It is unknown if the culture ...
Joó K, Trúzsi RL, Kálmán CZ, Ács V, Jakab S, Bába A, Nielsen MK.In Hungary, equine parasite control is mostly based on traditional approaches involving rotational anthelmintic treatment at regular intervals. Almost no farms utilize fecal egg counts (FECs) on a regular basis to guide deworming treatments. This approach is certainly not sustainable and is the major factor responsible for the current high levels of anthelmintic resistance. The aims of this study were to statistically analyze risk factors associated with strongylid egg count magnitude and prevalence. Fecal samples and horse data (age, pasture history, stocking density, anthelmintic history) we...
Nielsen MK, Doran D, Slusarewicz P.Fecal egg counts are essential monitoring tools in veterinary parasite control. In recent years, several groups have developed automated egg counting systems based on image analysis and deep learning algorithms. Work in our laboratory demonstrated that an automated system performed with significantly better precision than traditional egg counting techniques. However, while the counting process is no longer operator dependent, the pre-analytical homogenization steps still are. This study aimed at evaluating the influence of sample homogenization on diagnostic performance on an automated equine ...
Gómez-Cabrera K, Salas-Romero J, Sifontes JA, de la Torre Cánova R, Salas JE, Nielsen MK.For the past several decades, selective anthelmintic therapy (SAT) has been recommended in temperate climate countries for controlling gastrointestinal parasites in horses. However, the feasibility of this approach in tropical climates remains unknown, given the very different parasite transmission patterns and a larger representation of working equids. The aim of this study was to evaluate the bio-economic feasibility of SAT in horses kept under tropical conditions of Camagüey, Cuba. Fecal egg counts were determined from 794 adult horses and used for evaluating three different putative treat...
Pihl TH, Nielsen MK, Olsen SN, Leifsson PS, Jacobsen S.Strongylus vulgaris is re-emerging in horses kept under surveillance-based parasite control regimens. Information on nonstrangulating intestinal infarction associated with S. vulgaris is needed to improve recognition of the condition. Objective: To describe the typical clinical presentation, laboratory findings, gross pathology, treatment and outcome of horses with nonstrangulating intestinal infarction. Methods: Retrospective case series. Methods: Nonstrangluating intestinal infarction was diagnosed in 30 horses with a localised intestinal infarction with concurrent signs of S. vulgaris mig...
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...
Nielsen MK, Steuer AE, Anderson HP, Gavriliuc S, Carpenter AB, Redman EM, Gilleard JS, Reinemeyer CR, Poissant J.Macrocyclic lactones have been the most widely used drugs for equine parasite control during the past four decades. Unlike ivermectin, moxidectin exhibits efficacy against encysted cyathostomin larvae, and is reported to have persistent efficacy with substantially longer egg reappearance periods. However, shortened egg reappearance periods have been reported recently for both macrocyclic lactones, and these findings have raised several questions: (i) are egg reappearance period patterns different after ivermectin or moxidectin treatment? (ii) Are shortened egg reappearance periods associated w...
Collobert-Laugier C, Hoste H, Sevin C, Dorchies P.Forty-two horses from Normandy (France) were examined post-mortem for small strongyle infections from October to March. In the positive horses, total worm numbers ranged from 234 to 90,247 (mean 11,297). Encysted larvae represented the major part of the total cyathostome burdens with a high percentage (83%) being early third stage larvae. They were mostly recovered from the caecum (48%) and ventral colon (40%) and were less present in the dorsal colon (12%). Adult cyathostomes were mainly located in the ventral colon (64%) and less frequently in the dorsal colon (27%) and caecum (9%). Twenty s...
Lester HE, Spanton J, Stratford CH, Bartley DJ, Morgan ER, Hodgkinson JE, Coumbe K, Mair T, Swan B, Lemon G, Cookson R, Matthews JB.Cyathostomins are considered to be the most important group of helminths to affect equids due to their high prevalence, potential pathogenicity and ability to develop anthelmintic resistance. Their control relies almost exclusively on frequent anthelmintic use. Currently, fenbendazole (FBZ), pyrantel embonate (PYR), ivermectin (IVM) and moxidectin (MOX) are licensed for use in horses in the UK. With no new anthelmintics likely to be licensed in the near future, it is essential that investigations into the efficacy of current anthelmintics in different locations are performed to help inform con...
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...
Osterman Lind E, Höglund J, Ljungström BL, Nilsson O, Uggla A.Faecal egg counts were performed during the first quarter of 1995 on samples from 1183 horses of varying breeds, ages and gender on 110 farms in 3 regions of Sweden. The majority of the horses had been treated with ivermectin or pyrantel when stabled the previous autumn. The risk of reinfection with strongyles between treatment and sampling was therefore considered to be minimal. Consequently, the results reflect primarily the occurrence of worms originating from inhibited strongyle larvae refractory to anthelmintic treatment. A total of 922 (78%) individuals were found to shed strongyle eggs,...
Lester HE, Matthews JB.Equine gastrointestinal nematodes are ubiquitous; in horses that graze contaminated pasture and that are not treated appropriately, large numbers of worms can accumulate, which can lead to serious clinical disease. Nematode control has traditionally followed interval treatment regimens, which involve regular anthelmintic administration to all horses based on the strongyle egg reappearance periods of each drug, usually defined around the time of licensing. Interval treatment programmes have resulted in substantial reductions in large strongyle disease, but have made major contributions to the d...
Hung GC, Chilton NB, Beveridge I, Gasser RB.In this study, molecular data sets were used to address the controversies relating to the systematics of strongyloid nematodes of equids utilising morphological data sets. DNA sequences of the first and second internal transcribed spacers (ITS-1 and ITS-2) of ribosomal DNA were determined for 30 species of equine strongyles and the systematic relationships reconstructed using phenetic and phylogenetic tree-building methods. The molecular data provided support for the hypothesis that the genera with large subglobular buccal capsules are ancestral to those with small cylindrical buccal capsules,...
Geurden T, van Doorn D, Claerebout E, Kooyman F, De Keersmaecker S, Vercruysse J, Besognet B, Vanimisetti B, di Regalbono AF, Beraldo P, Di Cesare A....The objective of the present study was to evaluate the efficacy of an oral treatment with ivermectin (IVM) or moxidectin (MOX) against gastro-intestinal strongyles in naturally infected horses by performing a faecal egg count reduction test (FECRT) and by monitoring the egg reappearance period (ERP) after treatment. Therefore, a field efficacy study with a randomised complete block design for each study site was conducted, with the individual animal as the experimental unit. At least 10 study sites in Italy, Belgium and The Netherlands were selected and animals were allocated to one of the two...
Martínez-Valladares M, Geurden T, Bartram DJ, Martínez-Pérez JM, Robles-Pérez D, Bohórquez A, Florez E, Meana A, Rojo-Vázquez FA.The objective of this study was to evaluate the status of anthelmintic resistance (AR) in ruminants and horses in Spain. The efficacy of commonly used macrocyclic lactones (MLs) - ivermectin (IVM) and moxidectin (MOX) - was measured in sheep, cattle and horses. In addition, albendazole (ABZ) and levamisole (LEV) were evaluated in sheep and oxibendazole (OXI) and pyrantel (PYR) in horses. Efficacy was evaluated based on the difference between the arithmetic mean pre- and post-treatment faecal egg count (in cattle and horses), or compared to an untreated control group (in sheep). AR was present ...
Höglund J, Ljungström BL, Nilsson O, Lundquist H, Osterman E, Uggla A.A survey was performed on the occurrence of some internal parasites in 461 horses (1-30 years old) slaughtered from October 1992 to September 1993 at the Linköping abattoir in central Sweden. Macroscopical examination was carried out specifically for parasites of the tear ducts and conjunctival sacs of the eyes, and of selected parts of the alimentary tract and cardio-vascular system. The following parasites were found in selected parts of the large intestine: encapsulated cyathostome larvae (in 35.6% of the horses), and mature strongyle worms (17.4%); in the stomach: Gasterophilus intestinal...
Andersen UV, Howe DK, Olsen SN, Nielsen MK.Parasites infecting horses are ubiquitous and clinically important across the world. The major parasitic threats to equine health are cyathostomins, Parascaris equorum, Anoplocephala perfoliata, and Strongylus vulgaris. Increasing levels of anthelmintic resistance reported world wide in equine parasites have led to recommendations of constructing sustainable parasite control programmes based on systematic surveillance of parasite levels. Regulations at the European Union level now make anthelmintics available on prescription-only basis and disallow prophylactic treatment. This emphasizes the n...
Sallé G, Guillot J, Tapprest J, Foucher N, Sevin C, Laugier C.Horses are infected by a wide range of parasite species that form complex communities. Parasite control imposes significant constraints on parasite communities whose monitoring remains, however, difficult to track through time. Postmortem examination is a reliable method to quantify parasite communities. Here, we compiled 1,673 necropsy reports accumulated over 29 years, in the reference necropsy centre from Normandy (France). The burden of non-strongylid species was quantified and the presence of strongylid species was noted. Details of horse deworming history and the cause of death were reg...
Näreaho A, Vainio K, Oksanen A.In order to assess the resistance situation against macrocyclic lactones in Parascaris equorum and against tetrahydropyrimidine derivatives in strongyles in Finnish trotter horses, 112 foals on 18 farms, mostly 1 year old, were examined for these parasites with a modified McMaster faecal flotation method. P. equorum positive foals (n=24) were given ivermectin orally at a dose of 200 μg/kg b.w., while strongyle positive but P. equorum negative foals (n=38) received pyrantel embonate orally at a dose of 19 mg/kg. Sixteen P. equorum infected foals, treated with ivermectin, also harboured strongy...
Nielsen MK.Clinically important equine parasites are ubiquitous in managed horse populations. The traditional approach to parasite control is frequent administration of anthelmintics to all horses on a farm. However, increasing levels of anthelmintic resistance is forcing horse owners and veterinarians to shift this control paradigm. Treatment regimens involving routine deworming of all horses throughout the year are now being replaced by more sustainable approaches, which take in to account the importance of maintaining adequate parasite refugia. The selective therapy principle has been recommended for ...
Nielsen MK, Monrad J, Olsen SN.In 1999, legislation in Denmark made anthelmintic drugs available only by prescription, and prohibited their use for routine, prophylactic treatment. A questionnaire survey was conducted in 2004 to determine current strategies for surveillance and control of equine strongyles used in Danish equine veterinary practices. Eighty-seven of 170 (51.2%) registered equine veterinary practices responded. Ninety seven percent of the respondents used faecal egg counts for diagnosis and surveillance, and 41% used larval cultures. Logistic regression revealed that the use of larval cultures was positively ...
Kuzmina TA, Kharchenko VA, Starovir AI, Dvojnos GM.Communities of intestinal helminths in horses are commonly studied post mortem. The study objectives were here to examine the species composition of the strongylid community in brood horses in Ukraine after deworming with an aversectin drug Univerm. The site distribution of the strongylid species was analysed according to dynamics of their expulsion in faeces. Forty-four horses of different ages from Poltavska oblast (22 horses), Kyivska oblast (17 horses) and Sumska oblast (5 horses) of Ukraine were included in the study. Horses were treated with Univerm anthelmintic (0.2% aversectin) at a do...
Mfitilodze MW, Hutchinson GW.A postmortem survey of 57 horses in tropical northern Queensland revealed 41 (89%) infected with intestinal strongyles. Thirty-five strongyle species (8 large strongyles and 27 small strongyles [Cyathostominae]) were recorded of which 9 species are reported from Australia for the first time. The 14 most prevalent small strongyles were Cyathostomum catinatum (in 76% of horses), Cyathostomum coronatum (65%), Cyathostomum pateratum (33%), Cyathostomum labiatum (30%), Cylicostephanus calicatus (70%), Cylicostephanus longibursatus (67%), Cylicostephanus goldi (43%), Cylicostephanus minutus (26%), C...
Fritzen B, Rohn K, Schnieder T, von Samson-Himmelstjerna G.Increasing prevalence of anthelmintic resistance in equine nematodes calls for a reexamination of current parasite control programmes to identify factors influencing control efficacy and development of resistance. Objective: To investigate if associations occur between prevalence of parasitic nematodes and management practices. Methods: German horse farms (n = 76) were investigated in 2003 and 2004. Information on farm and pasture management with respect to endoparasite control measures obtained using a questionnaire survey. Faecal examinations were performed in parallel. Results: Horses (n = ...
Boersema JH, Eysker M, Maas J, van der Aar WM.The reappearance of strongyle eggs in faeces after treatment with ivermectin or pyrantel embonate was investigated in 22 foals, 36 yearlings, and 45 adult horses on five Dutch horse farms. The results confirmed earlier studies which showed an egg reappearance period of 9 and 6 weeks after ivermectin and pyrantel treatment, respectively. There were no differences between the egg reappearance periods of foals, yearlings, and adult horses. The mean egg counts of the yearlings were, however, consistently higher than the mean egg counts of the adult horses and foals in both ivermectin- and pyrantel...
Pilo C, Altea A, Pirino S, Nicolussi P, Varcasia A, Genchi M, Scala A.A post-mortem survey was carried out on 46 Sardinian horses to evaluate the presence of Strongylus vulgaris and associated pathology. Horses were from local farms and had been treated with broad-spectrum anthelmintics at least 3 times a year. Examination of the cranial mesenteric arterial system (CMAS) showed parasite-induced lesions in all horses. S. vulgaris larvae were found in 39% of examined arteries, while their detection rate in coprocultures was 4%. Histology, carried out on 26 horses, showed mainly chronic and chronic-active lesions. Histometry showed a significant increase in thickne...
Hung GC, Gasser RB, Beveridge I, Chilton NB.The first and second internal transcribed spacer sequences of 28 morphologically-defined species of horse strongyle were characterized, and specific oligonucleotide primers were designed for some species based on the nucleotide differences. Utilizing these primers, a PCR approach was developed for the specific amplification of ribosomal DNA of Strongylus vulgaris, Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus or Cylicostephanus goldi. The method allowed the species-specific amplification of parasite DNA derived from faecal samples and/or copro-cultures, demonstra...
Andersen UV, Howe DK, Dangoudoubiyam S, Toft N, Reinemeyer CR, Lyons ET, Olsen SN, Monrad J, Nejsum P, Nielsen MK.Strongyle parasites are ubiquitous in grazing horses. Strongylus vulgaris, the most pathogenic of the large strongyles, is known for its extensive migration in the mesenteric arterial system. The lifecycle of S. vulgaris is characterised by a long prepatent period where the migrating larvae are virtually undetectable as there currently is no test available for diagnosing prepatent S. vulgaris infection. Presence of S. vulgaris larvae in the arterial system causes endarteritis and thrombosis with a risk of non-strangulating intestinal infarctions. Emergence of anthelmintic resistance among cyat...
Xiao L, Herd RP, Majewski GA.Efficacies of moxidectin and ivermectin were compared in four groups of eight ponies with natural parasite infections: placebo (Control), oral moxidectin gel at 0.3 mg kg-1 of body weight (Mox 0.3), oral moxidectin gel at 0.4 mg kg-1 of body weight (Mox 0.4), and oral ivermectin paste at 0.2 mg kg-1 of body weight (Ivermectin). Fecal samples were taken 0 and 2 weeks after treatment. Animals were necropsied and worms were collected 2 weeks after treatment. Moxidectin and ivermectin showed similar efficacy (99%) against adult cyathostomes, Strongylus spp., Triodontophorus spp. and Habronema musc...
Sargison N, Chambers A, Chaudhry U, Costa Júnior L, Doyle SR, Ehimiyein A, Evans M, Jennings A, Kelly R, Sargison F, Sinclair M, Zahid O.Understanding the composition of gastrointestinal nematode communities may help to mitigate or exploit parasite adaptations within their host. We have used nemabiome deep amplicon sequencing of internal transcribed spacer-2 (ITS-2) ribosomal DNA to describe the temporal and host species composition of gastrointestinal nematode communities following sampling of six Scottish ponies across 57 months. In the absence of parasite control, each horse showed seasonal trends of increases and decreases in faecal egg counts, consistent with the epidemiology of equine strongylid parasites, however, the c...
