Topic:Poisoning
Leucaena leucocephala toxicity in Brazilian horses. Leucaena leucocephala poisoning is reported in horses in different Brazilian regions. The poisoning occurred one month after the horses were introduced into paddocks invaded by the plant or after 10 days of consuming cut Leucaena administered as the only food. Affected horses showed moderate to severe hair loss on the mane and tail, orthokeratotic hyperkeratosis with marked follicular telogenization, and hyperplasia of thyroid follicular cells. Mimosin concentration in leaves (5.5 mg/g) was determined by a new HLPC-UV method which is also reported.
New Pathophysiological Insights from Serum Proteome Profiling in Equine Atypical Myopathy. Equine atypical myopathy (AM) is a severe environmental intoxication linked to the ingestion of protoxins contained in seeds and seedlings of the sycamore maple () in Europe. The toxic metabolites cause a frequently fatal rhabdomyolysis syndrome in grazing horses. Since these toxic metabolites can also be present in cograzing horses, it is still unclear as to why, in a similar environmental context, some horses show signs of AM, whereas others remain clinically healthy. Label-free proteomic analyses on the serum of 26 diseased AM, 23 cograzers, and 11 control horses were performed to provide i...
Range and Pasture Plants Likely to Poison Horses. Range and pasture toxic plants can poison horses. Many of these plants are noxious weeds that can dominate plant populations and replace healthy forages. Poisoning is often difficult to diagnose as the resulting plant-induced disease is similar to other infectious, toxic, and nutritional diseases. Identifying potentially problem plants, and observing what plants horses are eating, is essential in determining the risk of poisoning. If the risk is significant, it can drive management to invest in strategies to avoid exposure, animal disease, and suffering.
Investigative and Diagnostic Toxicology and Feed-Related Outbreaks. Incidences of feed contamination are rare even though enormous amounts of animal feed are manufactured. However, there are still some cases of feed-related illness in horses. Veterinarians play a crucial role in recognizing and mitigating these events and in assessing the severity of risks. Due to these risks, proper reporting and consultation with government and state agencies are crucial. Accurate diagnosis and identification of the source of poisoning are promising when a thorough case workup is performed and agencies such as veterinary diagnostic laboratories and the US Food and Drug Admin...
Cytotoxic Natural Products Isolated from Cryptogramma crispa (L.) R. Br. Parsley fern, , is a common fern in arctic-alpine regions, and even though this species has been known since ancient times and has been presumed to cause the poisoning of horses, its natural products have not previously been investigated. Here, we characterise 15 natural products isolated from the aerial parts of , including the previously undescribed compound 3-malonyl pteroside D. The structure determinations were based on several advanced 1D and 2D NMR spectroscopic techniques, Circular Dichroism spectroscopy and high-resolution mass spectrometry. The pteroside derivatives exhibited selecti...
Ionophores. Ionophores are a class of polyether antibiotics that are commonly used as anticoccidial agents and growth promotants in ruminant diets. Ionophores transport ions across lipid membranes and down concentration gradients, which results in mitochondrial destruction, reduced cellular energy production, and ultimately cell death. Cardiomyocytes are the primary target in equine patients when exposed to toxic concentrations and the clinical disease syndrome is related to myocardial damage. Animals can survive acute exposures but can have permanent heart damage that may result in acute death at future ...
Survival of formalin intoxication in a 13-year-old Thoroughbred gelding. Formalin intoxication via the gastrointestinal route has not been previously reported in the horse. Whereas ingestion of formalin in humans, although rare, is well documented. Majority of human cases are either accidental, suicidal or homicidal and often lead to fatality, with a reported lethal formaldehyde dose equating to 0.12 - 0.16 g/kg bwt. Objective: To describe a single case report of the clinical management of an adult horse referred to a veterinary teaching hospital following accidental administration of 10% formalin via nasogastric tube. Methods: A 13-year-old Thoroughbred gelding or...
Tissue Specific Distribution and Activation of Sapindaceae Toxins in Horses Suffering from Atypical Myopathy. Equine atypical myopathy is caused by hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG), the known protoxins of sycamore maple (). Various tissues from five atypical myopathy cases were analyzed but only HGA was found. Whether deamination of MCPrG has already occurred in the intestine as the first stage of metabolization has not been investigated. Activation of the protoxins to methylenecyclopropylacetyl (MCPA)-CoA and methylenecyclopropylformyl (MCPF)-CoA, respectively, occurred mainly in the skeletal muscles, as evidenced by very high concentrations of MCPA-carnitine and MCPF-carnit...
Equine Crofton Weed (Ageratina spp.) Pneumotoxicity: What Do We Know and What Do We Need to Know? Crofton weed (Ageratina adenophora) is a global and highly invasive weed, with ingestion causing severe respiratory disease in horses, leading to irreversible and untreatable pulmonary fibrosis and oedema. While reports of equine pneumotoxicity remain common in Australia and New Zealand, equine pneumotoxicity may be underdiagnosed in other countries where Crofton weed is endemic but poorly differentiated. The pathogenesis of Crofton weed toxicity following ingestion has been well described in a number of different animal models, including rodents, rabbits, and goats. However, induced toxicity ...
Acetogenin-induced fibrotic heart disease from avocado (Persea americana, Lauraceae) poisoning in horses. Poisoning by avocado (Persea americana) has been confirmed in sheep, goats, dogs, rabbits and ostriches. The clinical signs and lesions are attributed to the acetogenin, persin. Little is known regarding the epidemiology, clinical signs, lesions and therapy caused by acetogenin-induced heart damage. During the two-year study, we investigated a horse farm with six horses that often fed themselves with P. americana leaves or mature fruit pulp and skin on the ground. Two horses died, and one underwent necropsy, histopathology, and immunohistochemistry using the anti-cardiac troponin C (cTnC). Gro...
Two Cases of Suspected Poisoning With Goat’s Rue (Galega officinalis L.) in Horses. The present report describes two novel cases of suspected intoxication with Galega officinalis in 6- and 21-year-old Arabian mares displaying acute respiratory signs. Both animals showed signs of pulmonary edema at physical examination, with the oldest of the two also manifesting severe dyspnea and foamy nasal discharge. The mares were grazing on the same meadow with hay available ad libitum. Botanical analysis of the latter showed traces of the toxic plant Galega officinalis (L.), which has been daily ingested at a dose of around 14 g of dry matter for three days. Based on the respiratory sig...
Renal Lesions in Horses with Oleander (Nerium oleander) Poisoning. A presumptive postmortem diagnosis of oleander () poisoning is made based on the histological observation of cardiomyocyte degeneration and necrosis, which is considered to be a reliable diagnostic marker, and can be confirmed via the detection of oleandrin in tissues or fluids. However, cardiac lesions may not be present in every case, and autolysis can often preclude the identification of subtle changes in the cardiomyocytes. Several studies of experimental oleander poisoning have noted the presence of renal lesions in multiple mammalian species, and case studies of accidental exposure have ...
Determining an approximate minimum toxic dosage of diphacinone in horses and corresponding serum, blood, and liver diphacinone concentrations: a pilot study. Poisoning of nontarget species is a major concern with the use of anticoagulant rodenticides (ARs). At postmortem examination, differentiating toxicosis from incidental exposure is sometimes difficult. Clotting profiles cannot be performed on postmortem samples, and clinically significant serum, blood, and liver AR concentrations are not well-established in most species. We chose diphacinone for our study because, at the time, it was the publicly available AR most commonly detected in samples analyzed at the University of Kentucky Veterinary Diagnostic Laboratory. We determined an approximate ...
Effect of Ageratina adenophora on hepatic and pulmonic pathological lesions in horses. The effect of Ageratina adenophora on pathological characteristics of the liver and lungs as well as serum biochemical parameters in horses were investigated. Ten horses without ingestion history of Ageratina adenophora were classified into the control group, and 10 poisoned but survived horses with 3 months ingestion history were set as the case group. Results showed that serum AST, ALT, ALP, magnesium and phosphorus were elevated significantly, while creatinine was decreased remarkably. Hematoxylin and eosin staining of liver tissues showed diffuse swelling or destruction of hepatocytes, nar...
Analytical documentation of an Arabian horse fatality related to Oenanthe crocata poisoning. Analytical detection of Oenanthe crocata toxins in biological samples is challenging because of their instability, the lack of commercially available standards and the exceptionally low detection of these molecules using mass spectrometry. This work aims to report the used analytical methods that allowed identification of the main plant toxins in biological samples from an equid (an Arabian horse) fatality related to hemlock water dropwort (Oenanthe crocata Linnaeus) intake. Using both LC-DAD and LC-HRMS methods allowed identification (i) of oenanthotoxin in roots found on the site, root fragm...
Hematological and Serum Biochemical Changes and Their Prognostic Value in Horses Spontaneously Poisoned by Crotalaria spectabilis. Determining the prognosis of poisoning by plants containing pyrrolizidine alkaloids is usually challenging. This study aimed to identify important prognostic parameters that can determine the severity of spontaneous poisoning by in horses. Blood samples from 42 horses spontaneously poisoned by oats contaminated with seeds were evaluated. Complete blood counts (CBC) and serum biochemical tests [urea, creatinine, total protein, albumin, total and direct bilirubin concentrations, aspartate aminotransferase (AST), γ-glutamyl transferase (GGT), and creatine kinase (CK) activities] were performed...
Severe Inhibition of Long-Chain Acyl-CoA Enoylhydratase (EC 4.2.1.74) in a Newborn Foal Suffering From Atypical Myopathy. In horses, congenital defects of energy production from long-chain fatty acids have not been described so far. In contrast, inhibition of fatty acid degradation caused by the toxins hypoglycin A and methylenecyclopropylglycine from various maple species are observed frequently. These non-proteinogenic aminoacids are passed on placentally to fetuses or with collostrum or milk to newborn foals. Nevertheless, newborn foals become very rarely symptomatic. Vertical transmission apparently is not sufficient to induce clinical disease without a particular genetic constellation being present. One of t...
Rejection behaviour of horses for hay contaminated with meadow saffron (Colchicum autumnale L.). Extensively used grasslands are frequently utilised for hay production for equines. Especially, extensive meadows have a great variety of plant species, which may include plants that are poisonous for equines such as meadow saffron (Colchicum autumnale L.). To authors' knowledge investigations about horses` avoidance behaviour towards dried meadow saffron in hay are missing. Reports of farmers are contrary to clinical symptoms described in case reports and associated with meadow saffron in hay. Objective: The aim of this study was to determine the rejection behaviour of horses for hay contamin...
In Vitro Assays for the Assessment of Impaired Mitochondrial Bioenergetics in Equine Atypical Myopathy. Equine atypical myopathy is a seasonal intoxication of grazing equids. In Europe, this poisoning is associated with the ingestion of toxins contained in the seeds and seedlings of the sycamore maple (). The toxins involved in atypical myopathy are known to inhibit ß-oxidation of fatty acids and induce a general decrease in mitochondrial respiration, as determined by high-resolution respirometry applied to muscle samples taken from cases of atypical myopathy. The severe impairment of mitochondrial bioenergetics induced by the toxins may explain the high rate of mortality observed: about 74% of...
Approach to Toxicologic Emergencies. Equine toxicologic emergencies are relatively uncommon but can cause significant morbidity and mortality in a group of comanaged horses. The field veterinarian's role is to triage the situation, as well as the individual animal. Individual patient stabilization should focus on support of essential organ functions, providing time for treatments to have an effect or for elimination of the toxicant. Decontamination procedures can follow patient stabilization, if appropriate. Antidotes are often not available or feasible for equine intoxications. The field veterinarian should emphasize triage and ...
Crotalaria spectabilis poisoning in horses fed contaminating oats. The present report describes the clinical and pathological changes induced by the consumption of oats contaminated with Crotalaria spectabilis seeds by horses. Eighty horses were exposed to oats containing 10 g/kg of C. spectabilis seeds with 0.46% pyrrolizidine alkaloids, and 21 horses died within a 6-month period. Clinical signs included jaundice, apathy, a hypotonic tongue, ataxia, hyporexia, weight loss, aimless wandering, violent behavior, and proprioceptive deficits. Pathological findings were predominant in the liver and included periportal bridging fibrosis, megalocytosis, centrilobul...
Hepatogenous photosensitization in ruminants and horses caused by the ingestion of Chamaecrista serpens in Brazil. This study aimed to describe the first reports of outbreaks of hepatogenous photosensitization in cattle, sheep, and horses caused by spontaneous ingestion of Chamaecrista serpens, as well as to reproduce poisoning in sheep experimentally. Eleven photodermatitis outbreaks of unknown cause occurred in cattle, sheep and horses on nine farms in the semiarid region of Bahia, northeastern Brazil, between July 2017 and July 2020. Cutaneous lesions of photosensitization initiated until one week after the animals were introduced in paddocks invaded by the plant at the beginning of the rainy season. Th...
Equine dental and skeletal fluorosis induced by well water consumption. Two horses that consumed well water with high fluoride content exhibited clinical signs of chronic dental and skeletal fluoride toxicosis and were later euthanized and autopsied. Both horses had degenerative disease of multiple joints and multiple dental defects. Elevated fluoride concentrations were found in bone and tooth samples of both horses, well water, and feed. Microscopically, abnormalities were noted in bone and tooth samples, and consisted mostly of foci of cement necrosis and hypercementosis. Horses exhibiting bilateral, highly symmetrical dental and/or skeletal lesions, with chron...
Equine atypical myopathy: consumption of sycamore maple seedlings (Acer pseudoplatanus) by pastured horses is driven by seedling maturity and might be associated with phenolic compounds. Poisoning with L. in horses contradicts the hypothesis of coexistence between plants and vertebrate herbivores being mediated through antipastoral traits as toxins. However, incidental observations showed that horses evaded seedlings with primary leaves. The objective of the present cross-discipline study was (i) to analyse whether developmental stages of L. differed as to phenolics hypothesised as antipastoral traits, and (ii) to observe systematically the selection behaviour of pastured horses towards seedlings. Methods: Phenolic profiles of five developmental stages from fruits to seedl...
Acute, subacute and chronic sequelae of horses accidentally exposed to monensin-contaminated feed. Monensin is highly toxic to horses and inadvertent ingestion can result in cardiac injury and death. Objective: To describe sequelae of monensin ingestion and to determine clinical predictors of outcome. Methods: Observational clinical study. Methods: Physical examination, electrocardiogram and echocardiography were performed on 76 horses accidentally exposed to monensin-contaminated feed. Four horses were examined within 14 days of exposure (acute period), 29 horses were examined between 15 and 45 days post-exposure (subacute period) and 70 horses were examined 4-10 months after exposure ...
A new method for quantifying causative and diagnostic markers of methylenecyclopropylglycine poisoning. Up to now quantification of hypoglycin A in serum and urine in the range of nmols to μmols per liter plus the measurement of accumulated acyl conjugates have been used for the diagnosis of poisoning by fruits or seeds of in humans and animals. A second poison, methylenecyclopropylglycine, however, is known to occur in this material. The objective of our study was to develop and evaluate a method for the quantification of this compound suitable for test materials obtained from animals and man. Methods: Methylenecyclopropylglycine was extracted from serum and urine of a volunteer by a methanoli...
Acute fatal poisoning by spontaneous ingestion of Enterolobium contortisiliquum (Mimosidae) pods in horses. An outbreak of acute poisoning of horses by Enterolobium contortisiliquum pods is reported in the state of Goiás, Brazil. Three horses presented apathy, hyporexia, prostration, jaundice, recumbency and died in 24-48 hours. The main pathological findings were a yellowish liver with an enhanced lobular pattern, multifocal hepatic necrosis mostly in the midzones of lobules and sometimes with a random distribution across the hepatic lobes and swelling of hepatocytes. E. contortisiliquum trees has a wide distribution in South America and cases of poisoning have not been reported in horses.
Potential new sources of hypoglycin A poisoning for equids kept at pasture in spring: a field pilot study. Equine atypical myopathy in Europe results from hypoglycin A (HGA) exposure through the ingestion of samaras or seedlings of the sycamore maple tree. This pilot study aimed at better defining sources of HGA intoxication in spring. Samaras fallen on the ground and then seedlings were collected at two-week intervals from sycamore, Norway, and field maple trees over the spring 2016. In early April, rainwater from wet seedlings collected after a rainy night was harvested to be analysed. Mid-May, samaras of the box elder, common ash, and inflorescences of sycamore maples were collected on the tree....
Detection of equine atypical myopathy-associated hypoglycin A in plant material: Optimisation and validation of a novel LC-MS based method without derivatisation. Hypoglycin A (HGA) toxicity, following ingestion of material from certain plants, is linked to an acquired multiple acyl-CoA dehydrogenase deficiency known as atypical myopathy, a commonly fatal form of equine rhabdomyolysis seen worldwide. Whilst some plants are known to contain this toxin, little is known about its function or the mechanisms that lead to varied HGA concentrations between plants. Consequently, reliable tools to detect this amino acid in plant samples are needed. Analytical methods for HGA detection have previously been validated for the food industry, however, these technique...
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.