Suspected Nerium oleander (Oleander) poisoning in a horse

Toxic Garden and Landscaping Plants

Many popular ornamental shrubs are not only beautiful but also toxic when ingested in sufficient quantities. Common toxic landscaping shrubs in North America include yew (Taxus spp), oleander (Nerium oleander), and rhododendrons and azaleas (Rhododendron spp). Horses are often exposed when plant trimmings are placed within reach or discarded in pastures. Occasionally clippings or fallen leaves contaminate hay. Some plants are unpalatable unless dried and mixed with hay or lawn clippings but others are ingested more readily. In many cases, disease can be severe and treatment unrewarding; therefore, client education is critical to preventing serious and potentially fatal poisonings.

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). Grossly and histopathologically, there was severe cardiac fibroplasia. Immunohistochemically, there was a multifocal decrease or negative expression in the cTnC cardiomyocytes' cytoplasm. Persea americana leaves were confirmed in the alimentary tract using botanical anatomy and molecular techniques. The chemical investigation by (LC-ESI-MS) revealed the presence of the acetogenins, persin and avocadene 1-acetate from P. americana. Persin was present in leaves and fruits (seed and pulp), while avocadene 1-acetate was found in leaves and fruits (seed, peel, and pulp) with a higher concentration in the pulp. Four other horses have been examined by electrocardiogram, echocardiogram and serum Troponin 1 (cTnI). To establish a causal effect of consumption of P. Americana and heart fibroplasia in horses, long-time experiments must be carried out.

Oleandrin: A Systematic Review of its Natural Sources, Structural Properties, Detection Methods, Pharmacokinetics and Toxicology

Oleandrin is a highly lipid-soluble cardiac glycoside isolated from the plant Nerium oleander (Apocynaceae) and is used as a traditional herbal medicine due to its excellent pharmacological properties. It is widely applied for various disease treatments, such as congestive heart failure. Recently, oleandrin has attracted widespread attention due to its extensive anti-cancer and novel anti-viral effects. However, oleandrin has a narrow therapeutic window and exhibits various toxicities, especially typical cardiotoxicity, which is often fatal. This severe toxicity and low polarity have significantly hindered its application in the clinic. This review describes natural sources, structural properties, and detection methods of oleandrin. Based on reported poisoning cases and sporadic animal experiments, the pharmacokinetic characteristics of oleandrin are summarized, so as to infer some possible phenomena, such as enterohepatic circulation. Moreover, the relevant factors affecting the pharmacokinetics of oleandrin are analyzed, and some research approaches that may ameliorate the pharmacokinetic behavior of oleandrin are proposed. With the toxicology of oleandrin being thoroughly reviewed, the development of safe clinical applications of oleandrin may be possible given potential research strategies to decrease toxicity.

A Probable Fatal Case of Oleander (Nerium oleander) Poisoning on a Cattle Farm: A New Method of Detection and Quantification of the Oleandrin Toxin in Rumen

Oleander (Nerium oleander) is an ornamental plant common in tropical and sub-tropical regions that is becoming increasingly widespread, even in temperate regions. Oleander poisoning may occur in animals and humans. The main active components contained in the plant are cardiac glycosides belonging to the class of cardenolides that are toxic to many species, from human to insects. This work describes a case of oleander poisoning that occurred on a small cattle farm and resulted in the fatality of all six resident animals. Furthermore, the investigation of the poisonous agent is described, with particular focus on the characterization of the oleandrin toxin that was recovered from the forage and rumen contents. The innovation of this study is the first description of the detection and quantification of the oleandrin toxin by liquid chromatography-high resolution mass spectrometry (LC-HRMS) in rumen.

Pericardial Disease, Myocardial Disease, and Great Vessel Abnormalities in Horses

Pericardial, myocardial, and great vessel diseases are relatively rare in horses. The clinical signs are often nonspecific and vague, or related to the underlying cause. Physical examination usually reveals tachycardia, fever, venous distension or jugular pulsation, a weak or bounding arterial pulse, ventral edema, and abnormal cardiac auscultation such as arrhythmia, murmur, or muffled heart sounds. The prognosis depends on the underlying cause and the disease progression, and ranges from full recovery to poor prognosis for survival. This article focuses on the etiology, diagnosis, prognosis, and treatment of pericarditis, pericardial mass lesions, myocarditis, cardiomyopathy, and great vessel aneurysm or rupture.

Study of troponin, creatine kinase biomarkers, and histopathological lesions in experimental Nerium oleander toxicity in rats and mice

Introduction

Nerium oleander is a plant of the Apocynaceae family toxic to humans, animals, and insects. This study was performed to determine the cardiac and neurotoxicity of the plant extract by oral administration in Wistar rats and Balb/c mice and to compare the susceptibility of these animal models to oleander toxicity.

Material and Methods

Four groups of eight mice and eight rats received N. oleander extract orally while a fifth group was the control. Serum concentrations of the biochemical toxicity indicators, namely troponin and creatine kinase (CK), were determined and histopathological evaluation of the heart and brain was performed.

Results

In mice, CK and troponin concentrations were respectively 1.5 and 7 times higher than in the control group (P < 0.05), while in rats, they were 6–7 and 11 times higher. Hyperaemia, haemorrhage, and myofibrolysis, without infiltration of inflammatory cells, were observed in the heart. In the brain the authors observed hyperaemia associated with perivascular and perineuronal oedema, and in higher-dosed rats multifocal haemorrhagic and liquefactive necrotic lesions.

Conclusion

Oleander can affect serum levels of CK and troponin due to nervous and cardiac injuries. Rats showed more severe changes in the biochemical indicators and histopathological lesions than mice. Therefore, biochemical and pathological findings indicate that Wistar rats are more susceptible to the cardiac toxicity and neurotoxicity effects of N. oleander poisoning than Balb/c mice.

Study of Troponin, Creatine Kinase Biomarkers, and Histopathological Lesions in Experimental Nerium Oleander Toxicity in Rats and Mice

INTRODUCTION

Nerium oleander is a plant of the Apocynaceae family toxic to humans, animals, and insects. This study was performed to determine the cardiac and neurotoxicity of the plant extract by oral administration in Wistar rats and Balb/c mice and to compare the susceptibility of these animal models to oleander toxicity.

MATERIAL AND METHODS

Four groups of eight mice and eight rats received N. oleander extract orally while a fifth group was the control. Serum concentrations of the biochemical toxicity indicators, namely troponin and creatine kinase (CK), were determined and histopathological evaluation of the heart and brain was performed.

RESULTS

In mice, CK and troponin concentrations were respectively 1.5 and 7 times higher than in the control group (P < 0.05), while in rats, they were 6-7 and 11 times higher. Hyperaemia, haemorrhage, and myofibrolysis, without infiltration of inflammatory cells, were observed in the heart. In the brain the authors observed hyperaemia associated with perivascular and perineuronal oedema, and in higher-dosed rats multifocal haemorrhagic and liquefactive necrotic lesions.

CONCLUSION

Oleander can affect serum levels of CK and troponin due to nervous and cardiac injuries. Rats showed more severe changes in the biochemical indicators and histopathological lesions than mice. Therefore, biochemical and pathological findings indicate that Wistar rats are more susceptible to the cardiac toxicity and neurotoxicity effects of N. oleander poisoning than Balb/c mice.

Fatal Oleander Toxicosis in Two Miniature Horses

Two young American miniature horses from the same farm were evaluated by a veterinarian due to presence of lethargy, anorexia, and cardiac arrhythmias. Both horses were treated aggressively with IV fluids and other supportive measures. The first horse died approximately 72 hr after the start of clinical signs and the second horse was humanely euthanized due to poor response to treatment. Oleander toxicosis was suspected based on the types of clinical signs present and due to several oleander plants and dried leaves present on the property. Oleander toxicosis was confirmed by the presence of oleandrin in gastrointestinal contents and digoxin in the serum of second horse.

Clinical and pathological features of Nerium oleander extract toxicosis in wistar rats

BACKGROUND

Nerium oleander has been widely studied for medicinal purposes for variety of maladies. N. oleander has also been reported having noxious effects because of its number of components that may show signs of toxicity by inhibiting plasma lemma Na+, K+-ATPase. The present study was performed to scrutinize the toxic effect of N. oleander leaves extract and its clinical and pathological features in wistar rats.

RESULTS

Hematological analysis showed significant variations in RBCs count (P = 0.01), Hb (P = 0.001), Hct (P = 0.0003), MCV (P = 0.013), lymphocyte count (P = 0.015), neutrophil count (P = 0.003), monocyte count (P = 0.012) and eosinophil count (P = 0.006). Histopathological studies have shown that in T1 group noticeable infiltration of inflammatory cells was found with low level of vascular damage. In T2 group, increased proportion of binucleated and inflammatory cells, hepatic necrosis, widening of sinusoidal spaces and mild level of vascular damage was observed.

CONCLUSION

Taken together these findings we can conclude that N. oleander leaves extract significantly affects on experimental animals due to its toxicity. Efforts must be exerted to purify different chemical components from extract with no inflammation as this plant is utilized in folk medicine with narrow therapeutic indices.

Effect of Nerium oleander (N.O.) leaves extract on serum hepcidin, total iron, and infiltration of ED1 positive cells in albino rat

To gain insight into the hepatohistological alterations in noninjured rat liver, Nerium oleander (N.O.) leaves extract was injected intramuscularly to induce an acute phase reaction (APR). Histopathological changes were studied after 3, 12, and 24 h time course of sterile muscle abscess. Tissue integrity and any infiltration of inflammatory cells in the liver were investigated by Hematoxylin and Eosin and ED1 peroxidase stainings. The administration of N.O. leaves extract (10 mL/kg) in H & E stained sections showed a general vacuolization of cytoplasm resulting loss of polarity with prominent nucleoli after 3 h of induction. At 12 h, eccentric nuclei were also observed in the sections. Marked infiltration of leucocytes with predominate macrophages was also found after 24 h as seen by ED1 positive staining. In the present study, a possible relationship between serum hepcidin and total iron level was also investigated in vivo. An early increase of hepcidin and total iron level (3 h) with a maximum at 12 h (P < 0.01; P < 0.001) was observed. These changes indicate that sterile muscle abscess may induce APR resulting in hepatic damage which is evident with the recruitment of inflammatory cells into the organ.

Oleander toxicosis in equids: 30 cases (1995-2010)

OBJECTIVE

To determine clinical, laboratory analysis, and necropsy findings for equids with oleander toxicosis and to identify factors associated with outcome.

DESIGN

Retrospective case series.

ANIMALS

30 equids.

PROCEDURES

Medical records of equids with detectable concentrations of oleandrin in serum, plasma, urine, or gastrointestinal fluid samples and equids that had not received cardiac glycoside drugs but had detectable concentrations of digoxin in serum were identified via a medical records database search. Descriptive statistics were calculated for medical history, physical examination, laboratory analysis, and necropsy variables. Logistic regression analysis was used to identify physical examination and laboratory analysis factors significantly associated with outcome.

RESULTS

3 of 30 (10.0%) equids died before or immediately after arrival at the hospital. Of the other 27 equids, 23 (85.2%) had gastrointestinal tract abnormalities, azotemia was detected for 19 (70.4%), and a cardiac arrhythmia was ausculted for 18 (66.7%). Mortality rate for all equids was 50.0%; mortality rate for hospitalized equids was 44.4%. The most common cause of death was cardiac dysfunction. Odds of survival to discharge from the hospital were lower for equids with cardiac arrhythmias versus those without arrhythmias and decreased with increasing Hct and serum glucose concentrations. Odds of survival increased with increasing serum chloride concentration and duration of hospitalization.

CONCLUSIONS AND CLINICAL RELEVANCE

Equids with oleander toxicosis frequently had simultaneous gastrointestinal tract, cardiac, and renal problems. Oleander intoxication should be a differential diagnosis for equids with colic in geographic areas where oleander is found, especially when azotemia or cardiac arrhythmias are detected concurrently.

Experimental oleander (Nerium oleander) intoxication in broiler chickens (Gallus gallus)

Dried leaves of oleander were orally given at a single dose of 500 mg/kg body weight to 20 clinically healthy male chickens. Clinical signs of toxicosis began to appear about 1 h after receiving the oleander and included hypersalivation, vomiting, diarrhea, deep depression, and sudden death. Also, hyperemia in the combs and wattles was obviously seen. Electrocardiograms (ECG) were repeatedly recorded at 30 min intervals. ECGs findings included increasing the QRS duration in some birds and various kinds of arrhythmias. Bradycardia was the most frequently detected finding (30.43%). During necropsy, there were congestion and hemorrhages in the visceral organs particularly in heart, liver, kidney, and lung. Histopathology revealed myocardial cell necrosis with hyperemia and hemorrhage, severe diffuse pulmonary congestion and edema, severe renal congestion and hemorrhage with tubular necrosis, and coagulative necrosis of hepatocytes with hyperemia and hemorrhage. There were also congestion, mild epithelial necrosis and desquamation with infiltration of mononuclear inflammatory cells in the proventriculus of all birds. There was also mild to moderate congestion in the intestines with scattered necrosis of surface enterocytes. The lack of information about the toxicity of oleanders in poultry was the main cause for this study. The results suggest that chickens appear to respond to oleander poisoning in a manner similar to other species.

Oleander intoxication in New World camelids: 12 cases (1995-2006)

OBJECTIVE

To characterize the clinical and clinicopathologic effects and evaluate outcome associated with oleander toxicosis in New World camelids.

DESIGN

Retrospective case series.

ANIMALS

11 llamas and 1 alpaca.

PROCEDURES

Medical records from a veterinary medical teaching hospital from January 1, 1995, to December 31, 2006, were reviewed. Records of all New World camelids that had detectable amounts of oleandrin in samples of serum, urine, or gastrointestinal fluid were included in the study. Descriptive statistics were used to evaluate the history, physical examination findings, clinicopathologic data, and outcome of affected camelids.

RESULTS

11 llamas and 1 alpaca met the inclusion criteria of the study. Either oleander plants were present where the camelids resided (n = 7) or oleander plant material was identified in the hay fed to the camelids (5). One llama was dead on arrival at the hospital, and another was euthanized upon admission because of financial concerns. Of the 10 treated camelids, 9 had evidence of acute renal failure, 7 had gastrointestinal signs, and 4 had cardiac dysrhythmias on initial evaluation. The overall mortality rate was 25%, but the mortality rate for the 10 camelids that were medically treated was 10%.

CONCLUSIONS AND CLINICAL RELEVANCE

In New World camelids, oleander intoxication was associated with a triad of clinical effects (ie, renal, gastrointestinal, and cardiovascular dysfunction). Oleander intoxication often represented a herd problem but carried a fair to good prognosis if treated promptly. Oleander toxicosis should be considered a differential diagnosis in sick camelids.

Intoxicação natural e experimental por Nerium oleander (Apocynaceae) em bovinos no Rio Grande do Sul

Descreve-se a intoxicação natural e experimental por Nerium oleander em bovinos no Rio Grande do Sul, Brasil. Dois de oito bovinos morreram subitamente após consumirem folhas de galhos de N. oleander que haviam sido podados e jogados no piquete onde os animais eram mantidos. Não foram observados sinais clínicos em uma vaca, mas um terneiro de 4 meses de idade apresentou decúbito lateral, movimentos de pedalagem, vocalização e morte. As alterações macroscópicas mais importantes observadas na vaca morta naturalmente e em duas novilhas intoxicadas experimentalmente ocorreram no coração que apresentava petéquias e equimoses no átrio esquerdo, coágulos e hemorragias no endocárdio do ventrículo esquerdo e áreas levemente pálidas no septo interventricular e em porções do miocárdio dos ventrículos. Na histologia, havia necrose de coagulação de fibras cardíacas individuais e de pequenos agrupamentos, caracterizada por aumento de eosinofilia citoplasmática e núcleos picnóticos. Essas lesões eram mais acentuadas no músculo papilar. O diagnóstico foi fundamentado na presença da planta no potreiro onde estavam os animais, quadro clínico-patológico compatível e reprodução experimental em dois bovinos nas doses de 0,5 e 1,0g/kg de folhas frescas da planta.