Venomous Snakes Of Kenya&

Management Of Snake Bites

Venomous Snakes

•Elapidae: Cobras (Forest, Spitting and Egyptian), Mambas & Kraits..•Viperidae: Vipers (Russel’s, Saw-scaled, Pit viper), Adders & Rattlesnakes.•Atractaspididae: Burrowing asps, mole vipers.•Hydrophidae: Sea snakes. Though part of Elapidae.•Colubridae: Boomslang.

Elapids venom: Neurotoxic primarily.Viperid venom: Cytotoxic and Hemotoxic.Sea snakes: Myotoxic primarily.

•Dark olive, olive green, grayish brown or steel grey in color.•The name is because the inside of the mouth is inky black.•Not as fierce as people describe them.•When they sense danger they will slide off to the nearest hiding place.•Average length: Up to 14 feet.•A single bite has enough venom to kill 120-140 adults.•When threatened will hiss loudly and strike in quick succession.•Can lift more than 2/3rd of its body off the ground.•Fastest snake in the world.

•Venom: Neurotoxic and Cardiotoxic.•Lethal dose for man: 10 to 15 mg.•Flattens head, hisses loudly and repeatedly strikes.•100 to 120 mg delivered per bite.•Mortality: 100% without treatment.

Local symptoms: Limited to mild pain at bite site.Systemic symptoms: Tingling sensation in extremities, droopingof eyelids, sweating, excessive salivation, lack of muscle control,nausea, shortness of breath, confusion, and paralysis. Convulsions,respiratory failure, and coma with death ensues.

•East African Mamba or the common mamba.•Very shy and found on trees.•Bright green and no body markings.•Venom similar to black mamba.•Only a tenth as toxic.•Neurotoxic.•Potentially fatal and needs treatment.

•Found in Western Kenya.•Green head, Progressively dark body.•Almost black tail.•Venom similar to black mamba.•Neurotoxic.•Potentially fatal and needs treatment.

•Most number of deaths.•Most common and widespread snake in Africa.•Extremely ‘willing’ to bite.•About a meter in length and very fat.•Blunt and rounded snout, narrow neck.•Two dark bands on the head.•One on the crown and the other between the eyes.•Yellow to white belly with few colorations.•Relatively dull looking snakes.

•Hiss very loudly when threatened.•Keeps the fore-part of the body tightly coiled like the letter S.•Strikes suddenly and with great speed.•Strike with almost a distance of a third of the body.•100-350 mg venom yield per bite.•100 mg can kill a human being.•If untreated, death occurs after 24 hours.

•Local symptoms: Severe bruising, bleeding, swelling. Severe skin necrosis.•Systemic symptoms: Oedema, shock, watery exudate from puncture wounds, nausea and vomiting, subcutaneous bruising, painful swelling of lymph nodes.•Hypotension, weakness, dizziness, unconsciousness.•Gangrene, secondary infections, loss of digits and limbs.•Death by DIC, coagulation deficits, bad management!•ASV treatment of choice.

•Heaviest viper.•Longest fangs (55 mm) and most venom injected.•Identified by tiny horns and two stripes below the eyes.•Large triangular head and very narrow neck.•Forest puff adder, Gabon viper, swampjack, butterfly adder.•Very tolerant snakes and rarely hiss or bite.•Bite when severely provoked.•Average venom yield per bite: 200 to 600mg.•14 mg enough to kill a human being.

•Local symptoms: Rapid swelling, intense pain, blistering. Necrosis of skin with severe bruising. •Systemic symptoms: Uncoordinated movements, defecation, urination, swelling of eyelids and tongue, convulsions, loss of consciousness, hypotension, heart damage, dyspnoea, hematuria, hematemesis, coagulation abnormalities.•Local tissue damage might need amputation.•ASV treatment of choice.

•Small snakes no longer than 60 cm.•Pale buff, reddish, pale brown ground color.•Whitish to pink belly color.•Quite ready to bite and strikes alarmingly quickly.•Move generally by side winding motion.•When agitated makes noise by rubbing scales together.•Characteristic double 8 coil with head in the center.•Injects 12 mg of venom per bite.•Lethal dose for man: 5 mg.

•Local symptoms: Rapid swelling, intense pain, blistering. Necrosis of skin with severe bruising. •Local tissue damage might need amputation.•Systemic symptoms: Hemorrhage, coagulation defects, bleeding from multiple sites (hematuria, hematemesis, brain, gut). •Hypotension, shock and cardiac arrest.•Renal failure from intravascular hemolysis.•ASV treatment of choice.

Other Vipers

•Echis leucogaster (white-bellied carpet viper.)•Echis ocellatus (Ocellated carpet viper.)•Rhino viper (Bitis nasicornis)•Not much known about symptoms.•Venom characteristics same as Echis carinatus.•Treatment: ASV

•Most common cobra in Africa.•Raises hood when threatened and sharp, explosive hiss.•May grow up to 2 meters in length.•Large and depressed head with broad snout.•Generally tries to escape when threatened.

•175 to 300 mg venom in a single bite.•Neurotoxic venom like all cobras.•Local pain, swelling, bruising, blistering and necrosis.•Headache, nausea, vomiting, abdominal pains, diarrhea, dizziness, collapse, flaccid paralysis, convulsions.•Death by respiratory failure due to muscle paralysis.

•One of the biggest cobra species.•Maybe up to 300 cm in length.•Extremely quick and agile snakes.•Uniformly black on top and yellow on the bottom.•Black or yellowish brown head.•Stands very tall when threatened.•Raise hood when threatened and hiss loudly.•Venom is neurotoxic and same symptoms as all elapids.

•Black necked, Large brown and Red: Three types.•Ejects venom with considerable accuracy from 6-12 feet.•Most often venom into the eyes.•Pain, Headache, Conjunctivitis, corneal ulcers, anterior uveitis.•Untreated, can require removal of the entire eye.•Systemic symptoms possible and are similar to other cobras.

•Boomslang: Lives in trees and bushes.•All green, all brown, or green with black between scales.•Head dome-shaped with large eyes.•1.5 meters in length on an average.•Inflates neck like a balloon when threatened.•Bites appear like scratch than puncture marks.•Symptoms: Mainly bleeding syndrome.•Treatment: Monovalent ASV.

Other Snakes

•Night adder, Mole viper, Twig snake.•Several small vipers.•All non-venomous and do not need ASV.•Local symptoms need treatment.•Tetanus toxoid, antibiotics and painkillers.

Other Snakes

Snake Venom

•Haemo/Cardiotoxic: Act on heart and cardiovascular system.•Neurotoxic: Act on the nervous system.•Cytotoxic: Localized action at site of bite.•Myotoxic: Act on muscles.

Modified saliva from parotid glands.Potent mixture of enzymes, non-enzymatic substances, metals,non-toxic proteins and carbohydrates. Enzymes: Phospholipases A2, B, C, D, Hydrolases, Phosphatases,Proteases, Esterases, Acetylcholinesterase, Transaminase,Hyaluronidase, Phosphodiesterase, Nucleotidase and ATPaseand Nucleosidases.

Snake Venom

Neurotoxins. Elapids (Cobras) and Kraits.Low molecular weight and diffuse rapidly into systemic circulation.Flaccid paralysis of muscles.Ptosis (drooping of eyelids), Ophthalmoplegia,paralysis of the muscles of palate, jaw, tongue, larynx, neck andmuscles involved in swallowing.Finally muscles of respiration including diaphragm.Repeated vomiting, blurring of vision, headache, dizziness, vertigo,stupor and coma before death by respiratory failure.

Snake Venom

Haemotoxins/Cardiotoxins/Cytotoxins. Viperids.High molecular weight and diffuse slowly causing more local effects.Tachycardia, hypotension, ECG changes. Sudden cardiac death.Activation of coagulation with DIC.Severe circulatory shock.Massive intravascular haemolysis. Bleeding from multiple sites.Puncture wounds, GIT, urinary tract, injection sites, petechiae,Sub-arachnoid hemorrhage, intra-cranial bleeds.Renal failure following haemolysis.Some vipers are myotoxic and cause muscle necrosis and renal failure.All viper bites cause a good amount of local tissue destruction.

Snake Bites

Majority of bites from the non-venomous snakes.Over 50% of bites from venomous snakes: Hardly lethal.Snakes on the defensive seldom inject much venom.Humans are not preys for snakes and as such not much venom is wasted.A majority of bites are superficial.

Local Manifestations

Pain and tenderness with a reddish wheal over the bite site.Oedema, swelling and blisters.Local bleeding and petechial rash (vipers).Tingling and numbness over bite site (vipers).Necrosis with gangrenous changes.Tetanus and Gas Gangrene.

Systemic Manifestations

Fright, flight leads to quicker absorption of venom!Psychological shock and death.Pallor, sweating and vomiting.Elapid symptoms are quicker and viper symptoms delayed.Other symptoms as mentioned previously under each snake.Mortality rates higher in children.Mortality marginally higher with elapids than vipers.Mortality rapid in elapid bites and delayed in viper bites.

Snake Bite Identification

2 puncture wounds few mm to 4 cms apart.Depth: 1 to 8 mm.Sometimes not visible, at times only one fang mark.Repeated bites can lead to several puncture marks.Non-venomous snakes: Row of teeth impressions, no fang marks.Snake identification more important.

Laboratory Tests

Complete blood counts.Peripheral smear: Hemolysis.Prolonged clotting time and Prothrombin time (Vipers).Hypofibrinogenemia.Hyperkalemia and Hypoxia.Urinalysis: Hematuria, proteinuria, hemoglobinuria and myoglubinuria.ECG and EEG changes.

First Aid For Snake Bites•DO NOT WASTE TIME.•Reassurance and immobilization of affected part.•Crepe bandage over and proximal to site.•Just tight enough to occlude lymphatics and veins.•One finger space between the affected part and bandage.•Do not waste time catching or killing the reptile.•Apply a splint to immobilize the area.•Make sure the affected limb or part is kept still.•Transport to a hospital immediately.

First Aid For Snake Bites

DO NOT:•Cut and suck the wound.•Use ice over the wound.•Use alcohol.•Use tourniquets or constricting bands.

Specific Therapy•Anti Snake Venom is drug of choice.•Derived from hyperimmunizing horses.•Monovalent or polyvalent.•Only used when serious or life-threatening symptoms are seen.•Severe local symptoms also warrant use of ASV.•No specific dosage regimes.•50 mL: Local symptoms only.•100 mL: Coagulation defects and mild systemic symptoms.•150 mL: Serious systemic symptoms.

Specific Therapy

•Reconstitute the ASV with Normal Saline.•Inject 20 mL of the total dose slowly IV over 20 minutes.•Always use a test dose before injecting.•Timing: Start as soon as symptoms are seen.•Second dose 2 hours after or earlier.•Further doses depending on response every 6 hours.•Ideally an infusion with the ASV can be started and run slowly.•In case of vipers inject some ASV around the site of the bite.

Specific Therapy

•To prevent anaphylaxis:•Hydrocortisone 100 mg IV and an Anti-Histamine IM.•15-30 min before ASV.•1 mL of 1:1000 Adrenaline can be used sometimes.

Supportive Therapy

•Fresh whole blood in case of severe bleeding.•Volume expanders in shock.•Respiratory support for patients in failure.•Routine antibiotic cover for all cases.•Tetanus Toxoid.•Surgical debridement.•Analgesics.

SUMMARY

Snakes do not generally attack human beings unprovoked.They are reputed to be more afraid of man than vice-versa.Nevertheless once bitten, a wide spectrum of clinicalmanifestations may result. The emphasis for treatmentshould be placed on early and adequate medicalmanagement. Overemphasis on first-aid can be dangerousbecause its value is debatable and too much valuable timeis wasted in its administration.