Topic:Toxins
Toxins in horses refer to a variety of substances that can cause adverse health effects when ingested, inhaled, or absorbed through the skin. These substances can originate from plants, chemicals, feed contaminants, or environmental sources. Common toxins affecting horses include mycotoxins, heavy metals, and certain plants like ragwort and oleander. Exposure to these toxins can lead to a range of clinical symptoms, from mild discomfort to severe illness or death. Research in this area focuses on identifying toxic agents, understanding their mechanisms of action, and developing strategies for prevention and treatment. This page compiles peer-reviewed research studies and scholarly articles that explore the sources, effects, and management of toxins in equine health.
Equine feed contamination and toxicology. Feed as a cause of poisoning in horses can occur on small or large scales. It is challenging to work up cases of suspected feed contamination, but there are resources available to veterinarians and owners. Feed contamination can be chemical or biological. This article focuses on and provides examples of chemical feed contamination including misformulation, adulteration, and natural contaminants. Additionally, recommendations for feed sampling and diagnostic submission, including legal documentation, are included.
Toxic Causes of Intestinal Disease in Horses. Because most poisonings occur by toxin ingestion, the gastrointestinal system is the first exposed and, in most cases, it is exposed to the highest toxin concentrations. Consequently, enterocyte damage is common. However, because many toxins produce organ-specific damage, and enterocyte necrosis is easily confused with autolysis, many gastrointestinal lesions are overlooked or overshadowed by other clinical and pathologic changes. The objective of this work is to review several common toxins and poisonous plants that produce primarily gastrointestinal disease.
Use of split-free nano-liquid chromatography-mass spectrometry/high resolution mass spectrometry interface to improve the detection of α-cobratoxin in equine plasma for doping control. Cobra (Naja naja kaouthia) venom contains a toxin called α-cobratoxin (α-Cbtx) containing 71 amino acids (MW 7821 Da) with a reported analgesic power greater than morphine. In 2013, the first analytical method for the detection of α-Cbtx in equine plasma was developed by Bailly-Chouriberry et al, allowing the confirmation of the presence of α-Cbtx at low concentrations (1-5 ng/mL or 130-640 fmol/mL) in plasma samples. To increase the method sensitivity and therefore to improve the detection of α-Cbtx in post-administration plasma samples, a nano-liquid chromatography-mass spectrometry/hi...
Development and validation of an ultrahigh performance liquid chromatography-high resolution tandem mass spectrometry quantification method for hypoglycin A and methylene cyclopropyl acetic acid carnitine in horse serum in cases of atypical myopathy. Atypical myopathy (AM) is a fatal disease in horses presumably caused by hypoglycine A (HGA) from ingested maple seeds and its active metabolite methylene cyclopropyl acetic acid (MCPA). The aim of this study was the development and validation of a rapid and simple assay for HGA and MCPA-carnitine in horse serum and its application to authentic samples. Identification and quantification were carried out by ultra high performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-HRMS/MS) with full-scan/data-dependent MS/MS. Chromatographic separation was performed by isocrat...
Neosaxitoxin, a Paralytic Shellfish Poison toxin, effectively manages bucked shins pain, as a local long-acting pain blocker in an equine model. Local anesthesia is an effective method to control pain. Neosaxitoxin is a phycotoxin whose molecular mechanism includes a reversible inhibition of voltage-gated sodium channels at the axonal level, impeding nerve impulse propagation. The present study was designed to evaluate the clinical efficacy of Neosaxitoxin as a local long-acting pain blocker in horse bucked shins, and it was found to effectively control pain. While Neosaxitoxin and Gonyautoxin, another Paralytic Shellfish Poison (PSP) toxin, have been successfully used in humans as long-lasting pain blockers, this finding marks the fir...
Venom and Antivenom of the Redback Spider (Latrodectus hasseltii) in Japan. Part II. Experimental Production of Equine Antivenom against the Redback Spider. This is the first report on large-scale experimental production of an equine antivenom against the redback spider (Latrodectus hasseltii) lived in Japan. We captured 10,000 redback spiders in Japan and prepared the toxoids of crude venom extract, mixed the toxoids with a mineral oil adjuvant, and immunized healthy horses repeatedly over a period of several weeks. Thereafter, we separated the horse plasma, purified the γ-globulin fraction, and stocked it as a purified antivenom concentrate. Consequently, we manufactured approximately 6,500 vials of a single-dose freeze-dried test lot from a po...
Identification of hypoglycin A binding adsorbents as potential preventive measures in co-grazers of atypical myopathy affected horses. Intestinal absorption of hypoglycin A (HGA) and its metabolism are considered major prerequisites for atypical myopathy (AM). The increasing incidence and the high mortality rate of AM urgently necessitate new therapeutic and/or preventative approaches. Objective: To identify a substance for oral administration capable of binding HGA in the intestinal lumen and effectively reducing the intestinal absorption of the toxin. Methods: Experimental in vitro study. Methods: Substances commonly used in equine practice (activated charcoal composition, di-tri-octahedral smectite, mineral oil and activat...
Further investigation of equine fescue oedema induced by Mediterranean tall fescue (Lolium arundinaceum) infected with selected fungal endophytes (Epichloë coenophiala). AIMS To determine if equine fescue oedema (EFO) induced by grazing Mediterranean-type tall fescue (Lolium arundinaceum) infected with selected endophytes (Epichloë coenophiala) could be prevented by treatment with the corticosteroid, methylprednisolone, and anti-histamine, cetirizine, and to determine concentrations of lolines, specifically N-acetyl norloline (NANL), in grasses grazed by horses that did and did not develop EFO. METHODS Four horses were grazed on AR542-infected Mediterranean tall fescue pasture (from Day 0) for 7 days prior to being subjected to euthanasia. Two of these horses...
Effects of polymyxin-B on TNF-α production in equine whole blood stimulated with three different bacterial toxins. Polymyxin-B is used to treat equine systemic inflammation. Bacterial toxins other than lipopolysaccharide (LPS) contribute to systemic inflammation but the effects of polymyxin-B on these are poorly defined. Whole blood aliquots from six healthy horses diluted 1:1 with RPMI were incubated for 21 hr with 1 μg/ml of LPS, lipoteichoic acid (LTA) or peptidoglycan (PGN) in the presence of increasing concentrations of polymyxin-B (10-3000 μg/ml). A murine L929 fibroblast bioassay was used to measure TNF-α activity. Polymyxin-B significantly inhibited the effects of all three bacterial toxins. ...
Immunogenicity of phospholipase A2 toxins and their role in Streptococcus equi pathogenicity. Streptococcus equi subsp. equi (S. equi) is the causative agent of strangles, one of the most frequently diagnosed infectious diseases of horses worldwide. Phospholipase A toxins (PLA) cleave phospholipid molecules at position sn-2 contributing to the production of leukotrienes that are important inflammatory mediators. Two homologous phospholipases, SlaA and SlaB are encoded by the S. equi genome suggesting that PLA toxins may contribute to its pathogenicity. Here we report the immunogenicity and role of PLA toxins during natural and experimental infection of horses with S. equi. The levels o...
Characterization of the zoonotic potential of Toxoplasma gondii in horses from Rio de Janeiro State. The aim of this study was to perform a survey on the prevalence of anti-Toxoplasma gondii antibodies in horses from Rio de Janeiro State, Brazil. From 2012 to 2013, a total of 624 blood samples were collected from horses from the eight regions comprising Rio de Janeiro State (Baixadas Litorâneas, Serrana, Norte Fluminense, Noroeste Fluminense, Centro-Sul, Metropolitana, Médio Paraíba, and Costa Verde). All sera samples were tested for anti-T. gondii antibodies by performing the modified agglutination test with a cut-off of 1:25. Positive serology for T. gondii was detected in 22.8% (142/624...
Identification of LukPQ, a novel, equid-adapted leukocidin of Staphylococcus aureus. Bicomponent pore-forming leukocidins are a family of potent toxins secreted by Staphylococcus aureus, which target white blood cells preferentially and consist of an S- and an F-component. The S-component recognizes a receptor on the host cell, enabling high-affinity binding to the cell surface, after which the toxins form a pore that penetrates the cell lipid bilayer. Until now, six different leukocidins have been described, some of which are host and cell specific. Here, we identify and characterise a novel S. aureus leukocidin; LukPQ. LukPQ is encoded on a 45 kb prophage (ΦSaeq1) found i...
Serosurvey of anti-Toxoplasma gondii antibodies in sport horses from Paraiba state, Northeastern Brazil. Although the infection by Toxoplasma gondii in horses is usually asymptomatic, it may be characterized by the presence of tissue cysts and maintenance of detectable antibody titers. The aim of this study was to detect anti-T.gondii antibodies and to determine risk factors associated in sport horses from Paraíba State, Northeastern Brazil. A total of 138 apparently healthy sport horses of different age and gender were sampled. Anti-Toxoplasma gondii antibodies were detected in 16/138 (11.6%; 95% CI: 6.77-18.14%) horses by indirect immunofluorescence antibody assay (IFA). A significant associat...
Duodenitis-Proximal Jejunitis in Horses After Experimental Administration of Clostridium difficile Toxins. Duodenitis-proximal jejunitis (DPJ) is an acute sporadic gastrointestinal disorder of horses of unknown cause. Objective: We hypothesize that Clostridium difficile toxins are involved in the pathogenesis of DPJ in horses. The objective of this study was to determine whether experimentally delivered C. difficile toxins cause clinical signs and histologic lesions similar to those of naturally occurring DPJ. Methods: Six healthy mature mixed breed horses. Methods: Experimental study: animal model of animal disease. Fasted horses were administered crude C. difficile toxins via gastroscopy and moni...
Identification of the immunogenic epitopes of the whole venom component of the Hemiscorpius lepturus scorpion using the phage display peptide library. The venom of the Hemiscorpius lepturus scorpion contains mixtures of bioactive compounds that disturb biochemical and physiological functions of the victims. Hemiscorpius lepturus envenomation is recognized as a serious health concern in tropical regions. So far, there is no preventive procedure, and the main focus is on treatment of victims with an antiserum purified from hyper-immunized horses. Although antisera can neutralize the venom, they, in some cases, lead to anaphylactic shock and even death. Selection of peptides mimicking antigenic and immunogenic epitopes of toxins from random pep...
Pathological changes seen in horses in New Zealand grazing Mediterranean tall fescue (Lolium arundinaceum) infected with selected endophytes (Epichloë coenophiala) causing equine fescue oedema. To investigate whether Mediterranean tall fescue (Lolium arundinaceum (Schreb.) Darbysh. (syn Festuca arundinacea)) infected with selected fungal endophytes (Epichloë coenophiala (formerly Neotyphodium coenophialum)) caused equine fescue oedema when grown in New Zealand, and to examine the pathological changes associated with this intoxication. Methods: Horses were grazed on Mediterranean tall fescue that was infected with the endophytes AR542 (n=2), or AR584 (n=3), or Mediterranean tall fescue that was endophyte-free (n=2). Blood samples were taken up to 7 days after the start of feeding to ...
Presumptive Iatrogenic Microcystin-Associated Liver Failure and Encephalopathy in a Holsteiner Gelding. An 8-year-old Holsteiner gelding was presented for evaluation of anorexia, obtundation, icterus, and mild colic signs of 48 hours duration. History, physical examination, and initial diagnostics were suggestive of hepatic disease and encephalopathy. Microcystin toxicosis was suspected based on historical administration of a cyanobacteria supplement, associated serum biochemistry abnormalities, and characteristic histopathological changes. Microcystin contamination was confirmed in both supplement containers fed to the horse. Fulminant hepatic failure and encephalopathy progressed resulting in ...
Contamination with ergot bodies (Claviceps purpurea sensu lato) of two horse pastures in Northern Germany. Because the occurrence of Claviceps in European pastures may have been overlooked to cause serious health problem for grazing animals, we documented the degree of Claviceps contamination in two horse pastures and estimated whether the horses could have ingested a critical quantity of alkaloids. We counted the Claviceps sclerotia and determined alkaloid levels using high performance liquid chromatography with fluorescence detection. Depending on the location, the number of sclerotia varied from 0.09 to 0.19 per square meter (central area) and from 0.23 to 55.8 per square meter (border strips). ...
Equine atypical myopathy: A metabolic study. Atypical myopathy (AM) is a potentially fatal disease of grazing horses. It is reportedly caused by the ingestion of sycamore seeds containing toxic hypoglycin A. In order to study metabolic changes, serum and urine samples from nine horses with atypical myopathy and 12 control samples from clinically healthy horses were collected and then analysed using a high-performance liquid chromatography coupled with tandem mass spectrometry; serum metabolic profiles as the disease progressed were also studied. Metabolic data were evaluated using unsupervised and supervised multivariate analyses. Signif...
Development of a chicken-derived antivenom against the taipan snake (Oxyuranus scutellatus) venom and comparison with an equine antivenom. A chicken-derived antivenom (ChDAv) towards taipan snake (Oxyuranus scutellatus) venom was produced by purifying anti-taipan IgY from egg yolks of hens immunized with taipan venom. The productivity, antivenomic profile, neutralization ability, pharmacokinetic properties and immunogenicity of the ChDAv were compared with those of an antivenom produced in horses (EDAv). We found that 382 eggs are required to produce the mass of anti-taipan antibodies contained in one liter of equine hyperimmune plasma, and that 63 chickens would be needed to generate the amount of anti-taipan antibodies annually...
Effects of deoxynivalenol (DON), zearalenone (ZEN), and related metabolites on equine peripheral blood mononuclear cells (PBMC) in vitro and background occurrence of these toxins in horses. Both deoxynivalenol (DON), zearalenone (ZEN), and their metabolites are known to modulate immune cells in various species whereby viability and proliferation are influenced. Such effects were rarely examined in horses. Therefore, one aim of the present study was to titrate the inhibitory concentrations of DON, 3-acetyl-DON (3AcDON), de-epoxy-DON (DOM-1), ZEN, and α- and β-zearalenol (ZEL) at which viability and proliferation of equine PBMC were reduced by 50 % (IC50) and 10 % (IC10) in vitro. For evaluation of practical relevance of the in vitro findings, a further aim was to screen horses...
Passive immunisation, an old idea revisited: Basic principles and application to modern animal production systems. Immunisation by administration of antibodies (immunoglobulins) has been known for more than one hundred years as a very efficient means of obtaining immediate, short-lived protection against infection and/or against the disease-causing effects of toxins from microbial pathogens and from other sources. Thus, due to its rapid action, passive immunisation is often used to treat disease caused by infection and/or toxin exposure. However immunoglobulins may also be administered prior to exposure to infection and/or toxin, although they will not provide long-lasting protection as is seen with active...
Fumonisin B₁ (FB₁) Induces Lamellar Separation and Alters Sphingolipid Metabolism of In Vitro Cultured Hoof Explants. One of the most important hoof diseases is laminitis. Yet, the pathology of laminitis is not fully understood. Different bacterial toxins, e.g. endotoxins or exotoxins, seem to play an important role. Additionally, ingestion of mycotoxins, toxic secondary metabolites of fungi, might contribute to the onset of laminitis. In this respect, fumonsins are of special interest since horses are regarded as species most susceptible to this group of mycotoxins. The aim of our study was to investigate the influence of fumonisin B₁ (FB₁) on primary isolated epidermal and dermal hoof cells, as well as ...
Hypoglycin A Concentrations in Maple Tree Species in the Netherlands and the Occurrence of Atypical Myopathy in Horses. Atypical myopathy (AM) in horses is caused by the plant toxin hypoglycin A, which in Europe typically is found in the sycamore maple tree (Acer pseudoplatanus). Owners are concerned about whether their horses are in danger if they graze near maple trees. Objective: To measure hypoglycin A in the most common maple tree species in the Netherlands, and to determine whether concentration of toxin is a predictor of AM in horses. Methods: A total of 278 samples of maple tree leaves, sprouts, and seeds were classified by species. Mean concentrations of hypoglycin A were compared for the type of sampl...
Comparative genomic analysis of toxin-negative strains of Clostridium difficile from humans and animals with symptoms of gastrointestinal disease. Clostridium difficile infections (CDI) are a significant health problem to humans and food animals. Clostridial toxins ToxA and ToxB encoded by genes tcdA and tcdB are located on a pathogenicity locus known as the PaLoc and are the major virulence factors of C. difficile. While toxin-negative strains of C. difficile are often isolated from faeces of animals and patients suffering from CDI, they are not considered to play a role in disease. Toxin-negative strains of C. difficile have been used successfully to treat recurring CDI but their propensity to acquire the PaLoc via lateral gene transfe...
Rapid Microfluidic Assay for the Detection of Botulinum Neurotoxin in Animal Sera. Potent Botulinum neurotoxins (BoNTs) represent a threat to public health and safety. Botulism is a disease caused by BoNT intoxication that results in muscle paralysis that can be fatal. Sensitive assays capable of detecting BoNTs from different substrates and settings are essential to limit foodborne contamination and morbidity. In this report, we describe a rapid 96-well microfluidic double sandwich immunoassay for the sensitive detection of BoNT-A from animal sera. This BoNT microfluidic assay requires only 5 μL of serum, provides results in 75 min using a standard fluorescence microplate ...
Pyrrolizidine alkaloids in food and feed on the Belgian market. Pyrrolizidine alkaloids (PAs) are widely distributed plant toxins with species dependent hepatotoxic, carcinogenic, genotoxic and pneumotoxic risks. In a recent European Food Safety Authority (EFSA) opinion, only two data sets from one European country were received for honey, while one feed data set was included. No data are available for food or feed samples from the Belgian market. We developed an LC-MS/MS method, which allowed the detection and quantification of 16 PAs in a broad range of matrices in the sub ng g(-1) range. The method was validated in milk, honey and hay and applied to hon...
Effects of deoxynivalenol in naturally contaminated wheat on feed intake and health status of horses. The present study examined the short-term effects of deoxynivalenol (DON), administered at two different concentrations via a feed preparation using naturally contaminated wheat, on feed intake, liver and kidney metabolism and immunomodulatory properties in horses. Twelve geldings were randomly assigned to one of three dietary treatments for 21 days. DON was provided via naturally contaminated wheat (14.6 ± 6.5 mg DON/kg dry matter). The daily feed intake was adjusted to 4 kg of wheat and 1.7 kg of silage per 100 kg of body weight (BW). Horses were fed one of the following diets: control whea...
Hypoglycin A Content in Blood and Urine Discriminates Horses with Atypical Myopathy from Clinically Normal Horses Grazing on the Same Pasture. Hypoglycin A (HGA) in seeds of Acer spp. is suspected to cause seasonal pasture myopathy in North America and equine atypical myopathy (AM) in Europe, fatal diseases in horses on pasture. In previous studies, this suspicion was substantiated by the correlation of seed HGA content with the concentrations of toxic metabolites in urine and serum (MCPA-conjugates) of affected horses. However, seed sampling was conducted after rather than during an outbreak of the disease. The aim of this study was to further confirm the causality between HGA occurrence and disease outbreak by seed sampling during ...
The prevalence of antibodies to Toxoplasma gondii in horses in Changji Hui Autonomous Prefecture, Xinjiang, northwestern China. Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, which can infect warm-blooded animals and humans. The present study was performed to investigate the seroprevalence of T. gondii in horses in Xinjiang, northwestern China. A total of 637 blood samples were collected from seven regions in Changji Hui Autonomous Prefecture, Xinjiang in 2011 and assayed for T. gondiiantibodies using the modified agglutination test (MAT). Risk factors (age, gender, and region) related to seroprevalence were determined by a multivariate logistic regression analysis. A total of 200 horses (31.4%, 95%...