Spontaneous clinical toxicosis with Abrus precatorious Seeds in a dairy cow

Numerous toxic plants cause digestive problems in livestocks either through direct effects of the plant on gastrointestinal system or indirectly by affecting other organs with a secondary effect on digestive system. Abrin is one of the most toxic compounds ever known, requiring as little as 0.00015 percent of a person’s body weight to be fatal (Knight and Walter, 2003). Animals are infrequently poisoned. Few experimental studies were in the public domain. Not much clinical reports on spontaneous toxicosis with Abrus in livestock are available.
        
The hard and relatively impermeable coat of mature seeds possibly makes it considerably less toxic even if swallowed whole. However, they are more dangerous when the seeds are chewed or sucked because the toxic elements in the seeds are extracted and mixed with enzymes. It was claimed that all parts of this plant are toxic. Clarke and Clarke (1975) reported that the black and red seeds of A. precatorius, a perennial vine found throughout the tropics, contain the very poisonous phytotoxin, abrin, a substance very similar to ricin of castor-oil seeds. Significant numbers of literature on Abrin toxicity and their clinical management are available in human medicine; but no clinical case reports on A. precatorius in dairy cows was available. This case report seeks to document the observed clinical findings, it’s clinico-pathological changes as well as its electroc ardiograms. The efficacy of supportive therapy in the management of spontaneous toxicosis of Abrus precatorious Seeds is presented.
 
Case presentation
 
A cross bred dairy cow was presented to the Large Animal Emergency Medicine Referral Clinic of the Veterinary College and Research Institute, Orathanadu, Tamilnadu, India with a history of accidental spontaneous ingestion of seeds of Abrus Precatorious. About half a kilogram of freshly collected Abrus seeds were kept in a small basket, for making ornaments and placed on the outer corridor of a rural farm house and this was ingested by the cow during the morning hours. After few hours of ingestion, the farmer observed of red tinged fecal materials which later on turned in blood mixed diarrheic episodes. The cow went anorectic and was said to be dull and inactive by the evening. In the following night hours, the farmer observed of the presence of few numbers of undigested Abrus seeds in the diarrheic feces. The cow was presented to the Emergency Medicine Clinic on the next day morning along with fecal sample containing the Abrus seeds. In the teaching hospital’s history of with a bovine case load in excess of 30000 over the past five years this was the first affected cow and recovered fully with a veterinary interventions.
 
Clinical examination findings
 
Clinical inspection of the cow revealed it to be dull and depressed. The cattle was markedly thin and dehydrated, with brittle hairs. Physical examination revealed normal temperature (38.9°C), heart rate (84 beats per minute and tachypnoea (41/minute). Consistency of the rumen was doughy and it had sluggish ruminal motility (1/3minute). Other systemic examinations were unremarkable at the time of presentation of the cow. On rectal examination, yellowish mucus shreads along with seeds of Abrus precatorius was observed in the feces. Rumen fluid was aspirated by centesis and its analysis. It revealed (Selvaraj et al., 2007) a very sluggish rumen protozoal motility with a pH 7. Animal was kept in the Critical Care Unit under continuous monitoring for a period of 3 days. Pulse oximetery was continuously monitored. The tail, nasal septum and genital mucosa of this cow provided a continuous, stable and good signal for pulse oximetric assessment. Arterial haemoglobin oxygen saturation (SpO2) was found to be 90%.
 
Electrocardiography (ECG)
 
Basic electrocardiography was recorded and it was monitored subsequently in periodical intervals. The ECG was recorded on a bipolar base apex lead using Limb LEAD I. Animal was kept in a standing position without any tranquilizer or sedative. No clipping or shaving was carried out for electrodes attachment. The ECG was recorded, when animal was in a quiet state using alligator type electrodes. Electrodes were attached to the skin after cleaning it with ethanol and applying electrocardiographic jelly. The positive electrode of Lead I (left arm) was attached to the skin of fifth intercostal space just caudal to the olecranon, and the negative electrode (right arm) was attached on the jugular furrow about lower 1/3 of the left side of neck (Yogeshpriya et al., 2019). No major abnormality could be detected in the ECG tracings.
 
Clinical laboratory investigations
 
Hamatology analysis showed that there was a significant decrease in total white blood cell count (3.05×10³/cmm) and a mild reduction in the total erythrocyte count (4.9×10⁶/cmm). The hematocrit value was 30%. 
        
Biochemical values revealed a hypoproteinemia (4.2g /dl) with no significant changes in serum urea nitrogen and creatinine values. Mild Hypocalcemia (ionized calcium - 0.90 mmol/L), hypochloraemia (98 mmol/L) and hyponatremia (131.4 mmol/L) and hypoalbuminemia was observed. Total and ionized calcium levels were monitored using electrolyte analyzer.
 
Diagnosis and differential diagnosis
 
Clinically the case was diagnosed as spontaneous Abrus Toxicosis. The differential diagnoses could be many, depending upon the locale. Based on the history, clinical signs and differential diagnosis no other possible etiology could be suspected and the case was clinically confirmed as Abrus Precatorious seeds toxicity. Abrin Toxin Assay Facilities are not currently available in the state and hence no advanced laboratory testing for further confirmation could be done.
 
Treatment
 
Initially the case was treated with aggressive fluid therapy with the multiple electrolyte solution containing sodium acetate, sodium chloride, potassium chloride, dibasic potassium chloride and 5% dextrose at the dose rate of 10ml/kg body weight for 3 days. In addition, ruminatoric (Bolus Tonakind ®, Vetmankind) was given for 3 days to stimulate the rumen motility. Decontamination was attempted with partial removal of fluid ruminal contents using a stomach tube and rumen fluid extraction pump. About 2-3 litres were pumped out on the first day of case presentation.  Decontamination was suggested as the major mode of treatment of abrus poisoning as no other antitodes are available yet. A single dose of 500g of Activated charcoal was administered orally to the intoxicated animal as per the standard protocols for poison management in livestock.
        
On the first day after clinical presentation and treatment, the animal showed mild improvement in its rumination. The same treatment was continued on 2^nd day except for rumen content removal. The animal voided mucus coated feces. The rumen consistency remained doughy; on the second day laxatives 450grams (Magnesium sulfate at the dose rate of 1g/kg body weight) was added to therapy. On 3^rd day, the animal voided near normal dung with less mucus. The ruminal consistency turned towards resilient. About 2 litres of rumen cud along with 300grams of activated charcoal was fed to the animal in the form of small boli, which were made with locally available jaggery called ‘Panam Karuppatti’ (Palm Jaggery). The cow was discharged on 3^rd day from the critical care unit. Every day the case was reviewed telephonically. On day 7, a complete and uneventful recovery was reported by the owner.
        
Many a times plant poisoning goes unreported or undetected in India. If the signs are mild, such animals are not at all presented to hospitals. Only cases with severe signs are presented for veterinary intervention. Though plant poisoning is sporadically reported in India, Abrus toxicosis was an uncommon one. Given to the high degree of fatality associated with Abrin poisoning, any suspected case needs to be thoroughly assessed clinically and all possible therapeutic measures shall be initiated.
        
Abrus is commonly known as Indian or wild liquorice root and is a climbing plant found throughout India. Three principle varieties are described by Roxburgh: (1) With rose- colored flowers, seeds red with black eye; (2) Flowers, dark colored; seeds white with black eye; (3) Flowers white, seeds white. Only if the seeds are chewed and swallowed it releases lectin.
        
Abrus Precatorious seed contains the phytotoxin abrin, abric acid and probably other toxic ingredients. It is commonly known as Rosary bead in English or Kundumani in Tamil langauge and is an irritant poison affecting almost all major systems of the body with more damage to gastrointestinal system. Oral ingestion of whole seeds often does not produce serious illness since the shell protects the toxin from digestion (Shih et al., 1998). The documented mortality rate is 10 to 15% for a lethal dose of just 1-2 crushed seeds in humans. The damage is done by a Toxalbumin called abrin which is concentrated more in the seeds and released on crushing (Reedman et al., 2008) along with smaller concentrations of glycyrrhizin, aric acid and N-methyltryptophal.
        
Abrus precatorius contains both ricin and abrin, which are among the most potent toxins described. Seeds and foliage are all poisonous. In early stages of poisoning, the toxicosis may arise due to ricin in abrus and such animals were found to be dull. Later these animals showed signs of incoordination and in severe cases, there was profuse swelling, tetanic spasms of the muscles and convulsions were reported. Clinical toxicosis reflects primary damage to gastrointestinal tract and it includes violent gastroenteritis followed by weakness and death (Galey 1996). Abrin, which consists of abrus agglutinin (a haem aglutinin) and toxic lectins abrins a to d are the five toxic glycoproteins found in the seeds (Windholz, 1989). Abrin-a, one of four isoabrins from the plant, has the highest inhibitory effect on protein synthesis and consists of an A chain of 250 amino acids and a B chain of 267 amino acids (Tahirov et al., 1994). The LD₅₀ of abrin injected in mice is less than 0.1 μg/kg, making abrin one of the most toxic substances known (Klaassen 2001). Abrin is also present in the leaf and is known to have action on hyperactivity of the system (Burkill 1995).
        
Few previous studies have shown that the abrin caused alterations in hematological and biochemical variables, but still the information is insufficient to understand (Fodstad et al., 1979). In the mice models exposed to abrin were suffering from abdominal pain, bloody diarrhoea, inappetence and their general well being are found to be affected. Previous studies of rat models showed that there was no observed relative change in the total WBC count. This was attributed to the finding that toxic plants do not produce direct effect on white blood cells, such as neutrophils, lymphocytes, eosinophils and monocytes (Swenson and Reece 1993). But in the present case, the animal showed decreased white blood cell count. Excessive ingestion of a wide variety of plants or their products has been found to cause hypoproliferative or non-regenerative anaemia. This is a stem cell disorder, characterized by reduced production of all blood components in the absence of a primary disease process infiltrating the bone marrow or suppressing haemopoiesis (Olsen et al., 1984). However this reason could not be applicable in the present case, as it was not a chronic plant poison exposure.
        
Slightly lower values of Total Erythrocyte Count observed in this case might possibly be due to the loss of blood from the hemorrhage and ulceration of ruminal mucosa and intestinal tissue due to possible toxin release from the seeds. It was observed that the effects of anemia are greatly influenced by its severity, duration and rate of development (Macfarline et al., 2001). Adedapo et al., (2007) reported that the A. precatorius reduced erythrocyte counts due to decreased Haemoglobin concentration (Hb %).
        
The observed hypochloraemia and hypoglo- bulinaemia were consistent with the inappetence and fluid diet. In the present case no significant changes was observed in Creatinine and Serum Urea Nitrogen. These observations were in agreement with the observations of Sharma (2005) who have reported similar result with chloroformic extract of Abrus precatorious seeds in rats.
        
There are no commercial antidotes or efficacious methods to enhance the elimination of abrin. Merck and Company (Whitehouse Station, NJ) developed an antiserum in large animals (Antiabrin ® or Jequiritol ®) to control abrin - induced ocular inflammations. However such procedures are not available in India.
        
Clinical management of abrin intoxication which occurred via ingestion shall consist of ruminal content removal and feeding activated charcoal, cud transfer with fresh ruminal contents of healthier cattle as these were found to be helpful in the current study.
               
This report demonstrates that the importance of timely and aggressive intervention can help in successful management of individual cases of Abrin precatorious toxicosis.