Topic:Anthelmintic Treatment
Anthelmintic treatment involves the use of drugs to control parasitic worm infections in horses. These treatments target various types of internal parasites, such as strongyles, ascarids, and tapeworms, which can affect equine health and performance. The administration of anthelmintics is a common practice in equine management to reduce parasite burdens and minimize the risk of disease transmission. Different classes of anthelmintics, including benzimidazoles, macrocyclic lactones, and pyrantel, are used based on the specific parasitic threats and resistance patterns. This page compiles peer-reviewed research studies and scholarly articles that explore the efficacy, resistance development, and management strategies associated with anthelmintic treatment in horses.
Estimating the Prevalence and Factors Affecting the Shedding of Helminth Eggs in Irish Equine Populations. 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...
Species interactions, stability, and resilience of the gut microbiota – Helminth assemblage in horses. The nature and strength of interactions entertained among helminths and their host gut microbiota remain largely unexplored. Using 40 naturally infected Welsh ponies, we tracked the gut microbiota-cyathostomin temporal dynamics and stability before and following anthelmintic treatment and the associated host blood transcriptomic response. High shedders harbored 14 species of cyathostomins, dominated by . They exhibited a highly diverse and temporal dynamic gut microbiota, with butyrate-producing Clostridia likely driving the ecosystem steadiness and host tolerance toward cyathostomins infectio...
Epidemiological study on factors influencing the occurrence of helminth eggs in horses in Germany based on sent-in diagnostic samples. 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...
Egg reappearance periods of anthelmintics against equine cyathostomins: The state of play revisited. Cyathostomins are the most common and highly prevalent parasites of horses worldwide. Historically, the control of cyathostomins has mainly relied on the routine use of anthelmintic products. Increasing reports on anthelmintic resistance (AR) in cyathostomins are concerning. A potential method proposed for detecting emerging AR in cyathostomins has been estimating the egg reappearance period (ERP). This paper reviews the data available for the ERP of cyathostomins against the three major classes of anthelmintics, macrocyclic lactones, tetrahydropyrimidines, and benzimidazoles. Published peer-r...
Disseminated Halicephalobus gingivalis infection in a horse. A 19-y-old American Saddlebred gelding was evaluated for epiphora of the right eye and generalized cachexia. Initial examination revealed anterior uveitis without ulceration, for which treatment was initiated. Despite the initial response to treatment, the signs progressively worsened to blindness. Histologic examination of the enucleated eye revealed granulomatous panuveitis and optic neuritis with intralesional nematode larvae identified as . Over time and despite anthelmintic treatment, blindness developed in the left eye along with neurologic signs, and the horse was euthanized. Disseminat...
Anthelmintic efficacy in strongyles of horses in Northern Minas Gerais, Brazil. 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...
Shortened egg reappearance periods of equine cyathostomins following ivermectin or moxidectin treatment: morphological and molecular investigation of efficacy and species composition. 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...
Anthelmintic resistance of horse strongyle nematodes to fenbendazole in Lithuania. 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...
Efficient and Scalable Process to Produce Novel and Highly Bioactive Purified Cytosolic Crystals from Bacillus thuringiensis. Bacillus thuringiensis (Bt) is a Gram-positive soil bacterium that is widely and safely applied in the environment as an insecticide for combatting insect pests that damage crops or are disease vectors. Dominant active ingredients made by Bt are insect-killing crystal (Cry) proteins released as crystalline inclusions upon bacterial sporulation. Some Bt Cry proteins, e.g., Cry5B (formally Cry5Ba1), target nematodes (roundworms) and show exceptional promise as anthelmintics (cures for parasitic nematode diseases). We have recently described inactivated bacteria with cytosolic crystal(s) (IBaCC) ...
Comparison of the host response to larvicidal and nonlarvicidal treatment of naturally acquired cyathostomin infections in horses. This study aimed to collect information on local and systemic inflammatory responses, and goblet cell-associated components, following anthelmintic treatment with moxidectin and ivermectin in horses naturally infected with cyathostomin parasites. Thirty-six horses aged 2-5 years of age were randomly allocated to three groups. Group 1 received ivermectin/praziquantel (0.2 mg/kg), Group 2 received moxidectin/praziquantel (0.4 mg/kg) and Group 3 were untreated controls. Tissue samples from the Cecum, Dorsal and Ventral Colons were used for histopathological evaluation and preserved for RNA is...
Reduction of the nematode egg reappearance period in horses after anthelmintic therapy. 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 ...
Occurrence of Strongylid Nematode Parasites on Horse Farms in Berlin and Brandenburg, Germany, With High Seroprevalence of Strongylus vulgaris Infection. 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...
Reflections and future directions for continued development and refinement of guidelines for anthelmintic efficacy studies. This reflection paper complements the WAAVP (World Association for the Advancement of Veterinary Parasitology) general anthelmintic efficacy guideline, which outlines the general principles of anthelmintic efficacy evaluation across all animal host species. It provides background to the recommendations made in the WAAVP general anthelmintic efficacy guideline, with insights into the discussions leading to specific recommendations in the general guideline or the absence thereof. Furthermore, this paper discusses recent technological advancements with potential value to the evaluation of anthelm...
Comparison of FECPAKG2, a modified Mini-FLOTAC technique and combined sedimentation and flotation for the coproscopic examination of helminth eggs in horses. 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...
Helminths and their management in Swiss Army horses: differences between riding horses and pack horses evidence the need of improvement. 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...
Farmers’ perception on the control of gastrointestinal parasites in organic and conventional sheep production in Sweden. A questionnaire was sent to sheep owners in Sweden to get information about anthelmintic drug use. The survey also investigated how respondents experienced problems with gastrointestinal nematode infections (GIN) focusing on Haemonchus contortus. The response rate was 31% and included both conventional and organic farms. The use of anthelmintics was low (45%), among which a majority (76%) drenched ewes on a single occasion, mostly with ivermectin (59%) followed by albendazole (19%). Other drugs were used rarely, however, unawareness of GIN risk was high (19%), especially among respondents with...
Total Failure of Fenbendazole to Control Strongylid Infections in Czech Horse Operations. 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...
World association for the advancement of veterinary parasitology (WAAVP): Third edition of guideline for evaluating the efficacy of equine anthelmintics. This guideline have been developed to assist in the design, execution, and interpretation of studies to assess the efficacy of anthelmintic drugs against internal parasites of equines, including nematodes, cestodes, and larval instars of Gasterophilus spp. The design and execution of critical and controlled studies are outlined, and their advantages and disadvantages are discussed. Unique considerations for specific target parasites are included. Information is also provided on selection of animals, procedures for randomization, housing, feeding, dosage titration, dosage confirmation and field...
Cyathostomin resistance to moxidectin and combinations of anthelmintics in Australian horses. Cyathostomins are the most important and common parasitic nematodes of horses, with > 50 species known to occur worldwide. The frequent and indiscriminate use of anthelmintics has resulted in the development of anthelmintic resistance (AR) in horse nematodes. In this study we assessed the efficacy of commonly used anthelmintics against cyathostomins in Australian thoroughbred horses. Methods: Two drug efficacy trials per farm were conducted on two thoroughbred horse farms in the state of Victoria, Australia. In the first trial, the horses on Farm A were treated with single and combinations ...
Evaluation of risk factors affecting strongylid egg shedding on Hungarian horse farms. 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...
Feasibility of selective anthelmintic therapy to horses in tropical conditions: the Cuban scenario. 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...
A Survey of Control Strategies for Equine Small Strongyles in Lithuania. Anthelmintic resistance (AR) in equine cyathostomins is being reported all over the world. In Lithuania, however, the last study on this subject was published more than fifteen years ago, thus little is known about the current situation. The aim of this study was to determine the factors that may associated with the development of AR on equine studs in Lithuania. A questionnaire containing seven open-ended and nine closed multiple-choice questions about worm control strategies, use of anthelmintic substances and stable management practices was posted to 71 randomly selected horse establishment...
Prevalence of anthelmintic resistant cyathostomins in Prince Edward Island, Canada. Cyathostomins are the most common parasites of adult horses worldwide. Currently, the three classes of anthelmintics used to treat cyathostomin infections includes benzimidazoles, pyrimidines and macrocyclic lactones. However, due to widespread overuse, cyathostomins have developed varying degrees of resistance to all classes of anthelmintics. Fecal egg count reduction tests (FECRT) are currently used to determine the presence of anthelmintic resistance (AR), while egg reappearance periods (ERP) are used to investigate early macrocyclic lactone resistance. The objective of this study was to in...
Impact of fenbendazole resistance in Ascaridia dissimilis on the economics of production in turkeys. Feed conversion efficiency is among the most important factors affecting profitable production of poultry.Infections with parasitic nematodes can decrease efficiency of production, making parasite control through the use of anthelmintics an important component of health management. In ruminants and horses, anthelmintic resistance is highly prevalent in many of the most important nematode species, which greatly impacts their control. Recently, we identified resistance to fenbendazole in an isolate of Ascaridia dissimilis, the most common intestinal helminth of turkeys. Using this drug-resistant...
Metagenomic Analysis of Fecal Archaea, Bacteria, Eukaryota, and Virus in Przewalski’s Horses Following Anthelmintic Treatment. Intestinal microbiota is involved in immune response and metabolism of the host. The frequent use of anthelmintic compounds for parasite expulsion causes disturbance to the equine intestinal microbiota. However, most studies were on the effects of such treatment on the intestinal bacterial microbes; none is on the entire microbial community including archaea and eukaryotic and viral community in equine animals. This study is the first to explore the differences of the microbial community composition and structure in Przewalski's horses prior to and following anthelmintic treatment, and to dete...
Three-year study to evaluate an anthelmintic treatment regimen with reduced treatment frequency in horses on two study sites in Belgium. In the present study, an anthelmintic treatment regimen with reduced treatment frequency was evaluated in horses on two study sites in Belgium during three consecutive summer pasture seasons. Historically, the horses on both study sites were treated up to 6 times a year with ivermectin (IVM) or up to 4 times a year with moxidectin (MOX), and previous efficacy evaluations indicated a reduced egg reappearance period in some of the treated horses for both IVM (28 days) and MOX (42 days). In the present study, all horses were treated with IVM or MOX in the spring and in autumn. Faecal egg counts (...
Constitutive and differential expression of transport protein genes in Parascaris univalens larvae and adult tissues after in vitro exposure to anthelmintic drugs. The equine roundworm Parascaris univalens has developed resistance to the three anthelmintic substances most commonly used in horses. The mechanisms responsible for resistance are believed to be multi-genic, and transport proteins such as the P-glycoprotein (Pgp) family have been suggested to be involved in resistance in several parasites including P. univlaens. To facilitate further research into the mechanisms behind drug metabolism and resistance development in P. univalens we aimed to develop an in vitro model based on larvae. We developed a fast and easy protocol for hatching P. univalens...
Formulation of the nematophagous fungus Duddingtonia flagrans in the control of equine gastrointestinal parasitic nematodes. Equine gastrointestinal nematodiosis contributes to the lower productivity of these animals. There are growing reports of the emergence of nematodes resistant to the drugs used for decades in anthelmintic treatments. An alternative to the emergence of resistance may be the use of nematophagous fungi as a complementary method of treatment. Therefore, the objective was to evaluate the effects of the use of the product Bioverm® as a carrier of Duddingtonia flagrans, on pasture contamination level and equine parasitic burden. Sixteen mares were used, divided into two groups, one control and one t...
Effects of Gasterophilus pecorum infestation on the intestinal microbiota of the rewilded Przewalski’s horses in China. Horse botflies have been a threat to the Przewalski's horses in the Kalamaili Nature Reserve in Xinjiang of China since their reintroduction to the original range. As larvae of these parasites could infest the intestine of a horse for months, they could interact with and alter the structure and composition of its intestinal microbiota, affecting adversely its health. Nonetheless, there are no such studies on the rewilded Przewalski's horses yet. For the first time, this study characterizes the composition of the intestinal microbiota of 7 rewilded Przewalski's horses infected severely by Gaste...