ANIMAL BITES AND STINGS

TAOLE MOKOENA DPhil FRCSDEPARTMENT OF SURGERYUNIVERSITY OF PRETORIA

2013

BITES: ANIMALS, HUMANS, SNAKES AND INSECTS

Humans are not prey to any animal!Humans do not form the sole source of food for any

insect except few parasites such as lice, scabies, etc.

Importance of bites are:1. Wounding2. Allergic reactions3. Envenomation4. “Exotic” disease transmission

WOUNDING THROUGH BITES

1. General breach of epithelium- trauma- tetanus- other bacteria, e.g. vibrio spp

2. Inoculation with specific animal flora, e.g. Pasturella multicida, Cypnocytophaga carnimorsus carnemortis

3. Treatment directed at these- general debridement and delayed closure- Tetanus Prophylaxis- Antibacterial prophylaxis

Mokoena & Cliff 1997

Mokoena & Cliff 1997

Mokoena & Cliff 1997

Mokoena & Cliff 1997

Mokoena & Cliff 1997

Shark Attacks• Shark attacks are rare but attract much publicity esp since movies

JAWS• About 50 attacks reported annually worldwide about 10% fatal. RSA

accounts for 10% attacks • Main attacking shark species:

– Great white (Carcharodon carcharias)– Tiger ( Galeocerdo curvier) : indiscriminate feeder– Bull (Zambezi) (Carcharhinus leucas): roams fresh water rivers

• Most attacks are “non—aggression” and thus not fatal• Main fatalities associated with vascular injury and exsanguinating

haemorrhage

Woolgar et al 2001

Woolgar et al 2001

Woolgar et al 2001

Mokoena & Cliff 1997

Management of Shark Injuries

• Prevention– Shark nets– Modify human behaviour: prudent use of the oceans no discharge of raw offal and carcasses

• Stop Haemorrhage and resuscitation• Save a life• Preserve function• Avoid complications

Insect Stings and Bites

• Most are of nuisance value: minor local irritation

• Some cause morbidity: Large local reaction• Very few can be fatal: anaphylactic reation• Anaphylactic reaction not predictable

Recommended Readings

• TR Mokoena and G Cliff. Injury from bites: in Scientific Foundations of Trauma eds GJ Cooper, HAF Dudley etc al Chapter 26 p347-364. Butterworth-Heinemann Oxford 1997

• Woolgar JD, Cliff G, Nair R et al. Shark attack: Review of 86 Consecutive Cases. J Trauma 2001;50: 887-891

• Graft DF. Insect Sting Allergy Med.Clin. N.Am 2006;90: 211-232• Braitberg G and Segal L. Spider bites: assessment and management.

Australian Fair Physician 2009;38:862-867• Klotz JH, Klotz SA, Pinnas JL. Animal bites and stings with

anaphylactic pontential. J Emergency Med 2009; 36: 148-156

Graft 2006

ALLERGIC REACTIONS1. Many insects and fish species induce allergic reactions,

e.g. honey bees, wasps, spiders, scorpions2. Atopic individual especially at risk3. Treatment symptomatic

- adrenalin- antihistamines- corticosteroids

4. Prophylaxis - skin testing - Venom Immunotheraphy (VIT)

EXOTIC DISEASE TRANSMISSION

1. Insect borne diseases especially viral but also parasitic, including rickettsia, trypanosomiasis, malaria

2. Rabies- endemic in South Africa- wild reservoir includes birds and rodents- dogs main transmitters to humans- no specific treatment except antiserum- Rabies control important

3. Human rabies vaccine- attenuated virus traditionally- genetically engineered vaccine now available

ENVENOMATION1. Mostly from snakes2. Most snakes harmless3. Types of venom• cytopathic – tissue necrosis• Haemolytic – haemolysis• Haemorrhagic

-DIC-Fibrinolytic

• Cardiotoxic• Neurotoxic

Most venoms are a mixture4. Treatment

- antivenom- supportive

5. Prophylaxis

VIPERIDAE – ADDERS – VENOM MOSTLY CYTOTOXIC

MAJOR ADDERSPuff AdderA short, fat, sluggish snake which is common and aggressive; responsible for most serious

bites.Gaboon AdderVery rare; found in the north eastern coastal areas of KwaZulu-Natal; important as its venom

is very potentMINOR ADDERSBerg AdderCommon in hiking areas of Drakensberg and Eastern Cape; important as, unlike other adders,

the venom is neurotoxic.Horned AdderErect scale above each eye; uncommon; found in drier areas of NE Cape and NamibiaNight AdderCommon; confused with egg eaters; bites not infrequent.Side Stabbing AdderBurrowing adderNot an adder but included in this group as it has cytotoxic venom; able to extrude its fangs

from the side of its mouth; herpetologists frequently get bitten.

COLUBRIDAE – BOOMSLANG – VENOM MOSTLY HAEMOTOXIC

BoomslangA long slender green snake with marked

colour variation; may be olive brown; always a yellow belly and big eyes.

Vine / twig snakeAn unusual and beautiful snake.

ELAPIDAE – COBRAS AND MAMBAS – VENOM MOSTLY NEUROTOXIC

NEUROTOXIC SPECIESMambasBlack, green, Jameson’s; all very long large aggressive and highly

dangerous snakes with a potent neurotoxin.CobrasCape, forest, Egyptian; common and almost as dangerous.RinkhalsHas both cytotoxic and neurotoxic properties to its venom; it is a good

spitter and excellent “shammer”.OthersCoral and shield snakes, yellow-bellied sea snake; uncommon on South

African shores.CYTOTOXIC SPECIESM’feziMozambique spitting cobra, black spitting cobra and barred cobras.Garter SnakeAlso neurotoxic features