After reading this article you will learn about the various venom bites and stings.
Snakes:
The highest number of snake bite cases in man and in animals have been observed in West Bengal, Uttar Pradesh, Maharashtra, Tamilnadu and Kerala. Out of 3000 species of snake, 375 species are poisonous. Venomous snake bites are responsible for more than 1,00,000 animal deaths in the world annually.
Farm animals are more likely to be bitten on Jaw, Pigs are not highly susceptible due the extensive subcutaneous fat depots. Sheep may be bitten on udder. Horse appears mostly to be much more susceptible to venomous than any other species. The Families comprising venomous snakes are Hydrophinae, crotalinae, Elapinae, Viperidae.
1. Hydrophinae.
Sea snakes venom is more toxic.
2. Elapinae
(a) Bangaurus calrulens (Indian krait)
(i) Bangaurus fasciatus (Banded krait)
(ii) Bangaurus niger (Black Krait)
(b)
i. Naja naja (common cobra)
ii. Naja hanna (King cobra)
(c)
(i) Calliophis macclellandii
(ii) Calliophis molarurus
(iii) Calliophis nigrescene
3. Viperidae
(a)Vipera
Vipera russelli (Russells viper)
4. Crotalinae (pit viper)
(a) Agkistrodon
Agkistrodon himalayans (Himalayan pit viper)
Agkistrodon rhodostome (Malayan pit viper).
(b) Trimeresurus- T. anamallenis
T. gramineus
T. monficoba
Venom Characteristics:
It is thought that neurotoxin consists of two active principles, one causes paralysis of the respiratory system and the other causes the failure of the cardiac movement. Death in cobra bite is caused by respiratory failure. Cardio toxin affects the cross striated muscles and has not effect on the nerves. It directly affects cardiac muscles and is responsible for cardiac arrest.
Mechanism of Action:
At-least four toxic actions can result from snake venom. Different snakes have different combinations of toxins in their venom. The toxins consist necrotizing coagulant fractions as well as neurotoxic and haemolytic fractions.
The effect of snake bite is dependent on the size and species of snakes, the size of bitten animal and the location of the bite particularly with reference to the thickness of the hair coat and the quality of subcutaneous fat. The neurotoxins cause initial stimulation of the CNS followed by paralysis. Effects of the other toxins cause local tissue necrosis, capillary damage and haemolysis.
Clinical Signs:
A. Large Animals:
Snake bites cause a local swelling, severe pain, excitement and anxiety. The bites on head causes severe swelling that cause difficult respiration. Other symptoms of snake bites include pupil dilatation, excessive salivation, Hyperasthesia, tetany, depression, recumbency leading to paralysis. Cobra bite does not cause local swelling. However, the animals surviving after the bite develop local swelling due to bacterial infection 3 to 4 days later. Cobra bite causes excitement with convulsions and death due to asphxia.
B. Dogs and Cats:
Clinical signs manifested in cats, bitten by tiger snake are dilated pupil, dyspnoea, hypothermia, hind ataxia and glycosuria. In dog, vomiting, tachypnoea, hyperthermia and paralysis has been observed. Oedema and heamomrrhage are the most obvious signs in case of dogs and cats.
Death Times:
Death is more rapid after cobra bites and prolonged after viper bites. However, the death depends on relative absorption of the smaller venom molecules directly through the blood stream. In rare case the venom may be injected by the snake directly into a vein. Death occurs within 1 to 10 hours in dogs and up to 48 hours in horses.
The farm stocks considerably of their larger size seldom die as a direct result of snake bite, but lack of medical attention may result in serious secondary damage. Bites on muzzle, head or neck may be fatal when dyspnoea results from excessive swelling.
Diagnosis:
It is difficult to diagnose unnoticed snake bite. However, many times the snake bite is seen and diagnosis is very easy. When possible owners should be asked to bring dead snake if it has been beaten without mutilating the snake’s head. Head morphology of snakes helps in identifying whether the bites are from poisonous or non poisonous snakes.
The most important diagnostic factor in identification of snake bite is presence of fang marks. The fang marks available in snake bite cases are usually in the centre of swollen area. There is severe swelling around the bite and dark bloody fluid may ooze from the fang wounds. Hair may hide the fang marks, and sometimes only one fang mark is seen.
Treatment:
1. Prevent or retard venom absorption locally.
2. Remove the venom locally.
3. Neutralize the venom locally.
4. Prevent local complication.
Local Treatment:
Application of a tourniquet above the bite to restrict the venom but not the arterial circulation. The tourniquet should be placed over the bite for 20 minutes, and at intervals of 2 to 3 minutes reapplied. If the snake is killed it should be kept for proper identification. The bitten area should be removed through a incision (1/2 inch length x 1/2 inch depth) made across the fang marks. The incised wound should be squeezed and suction applied for 10- 30 minutes. The oral suction is not recommended.
Systemic Treatment:
Antivenin:
It greatly reduces the tissue necrosis. It can be given systemically as well as locally but its value is partly dependent on its being given early.
Dose of Polyvalent Serum:
2 units/150 kg body weight for large animal and 10 units/20-40 kg body weight in case of small animals I/V. The antivenin is best administered if diluted with 500-1000 ml of 5% dextose solution.
A. Antibiotic:
Broad spectrum antibiotics are indicated to combat bacterial infections.
B. Antitoxin:
Clostridial bacteria have isolated from the snake mouth. The dose of anti-tetanus serum 1500-3000 i.u., (s/c) has been recommended,
C. Anti-Inflammatory:
Cortisone is valuable drug and render a protection against possible anaphylaxis after the treatment.
Supportive Therapy:
1. Fluids are indicated to combat shock and dehydration.
2. Epinephrine is also effective in combating shock.
3. Pethidine may be used to alleviate pain or excitement.
4. Vit-C, and Cal-gluconate are useful in preventing haemolysis.
Enzyme therapy: Proteolytic enzymes may be given.
5. Blood transfusion and haemodialysis.
Other Measures:
(i) Potassium permanganate should never be used locally as it does more harm.
(ii) Infiltration to bitten area with 5% soap solution in case if it is a viper bite.
(iii) Anticoagulant therapy has not proved to be beneficial.
(iv) All victims of venomous snake bite should be closely watched for 72 hrs.
Bee Stings:
Bee stings are multiple in nature and cause severe local swellings in animals. Bee stings in horses cause excitement due to pain and may include diarrhoea, haemoglobinuria, jaundice, tachycardia and prostration. Bee stings on head of animals include dyspnoea due to severe local swelling. Bee stings are not fatal in general.
Treatment:
1. Local application of a week solution of ammonia or sodium bicarbonate.
2. If prostration is severe nervous stimulants may be given.
Toads:
Toads do not contain poisonous apparatus like snakes. However, glands present in their head secretes various toxins e.g., steroid, bufogenin, bufotalin, and butotoxin which act like digitalis. In addition to the above toxins bufotenine and serotonine are also found in the glands present in their head.
Symptoms:
Dogs and cats that generally attack toad show symptoms of distress and excessive salivation.
Treatment:
Treatment depends upon species of toads. In case of Bufo vulgaris no specific treatment is essential and animals recover quietly. In case of Bufo marinas which causes prostration, convulsion and death within 15 minutes.
The following treatment is adopted:
(i) Wash the mouth with fresh water.
(ii) Atropine as an specific antidote (Medium size dog-1/100 to 1/50th grain atropine sulphate, i.v. followed by 1/200 grain, s.c.).
(iii) Sodium Pentobarbitone is given to control convulsions.
(iv) Leptazol (i.m.) be given to control depression.
(v) Oxygen therapy may be given in severe cases.