Anti-Venom

How Anti-Venom is Produced

Snake venom is collected from snakes through a process called milking. Small quantities of snake venom are injected into a horse, which is able to produce enough antibodies to neutralize the effect of the venom. Over a period of time, the dose of snake venom is increased, with the outcome being a horse with a large number of antibodies in its system.

Blood is taken from the horse which is spun in a centrifuge enabling collection of the horse blood serum. The horse blood serum is stored in a fridge and used as antivenom for snakebite. The most effective treatment for a snakebite is a specific antivenom application for a specific species of snake.

Premedication of antihistamines is often required to reduce the possibility of complications associated with a patient’s reaction to antivenom.

When is Antivenom Required?

The majority of snake bites in Australia do not require antivenom. Venom Detection Kits can be used by hospitals to determine the type of snake venom. Specific antivenom (monovalent) is only administered when the snake responsible for the bite has been identified and the clinical state of the patient indicates that it is necessary.

A less effective general antivenom (polyvalent) can be administered when the species of snake is unknown.

Red Bellied Black Snake (Pseudechis porphyriacus) antivenom is used for a number of closely related species including the Mulga Snake (Pseudechis australis) pictured above.

Snake Venom

Snake venom is one method adopted by snakes to immobilize their prey. Venom behaves like a modified form of saliva that is introduced into prey items via specialized hollowed teeth known as fangs. The purpose of venom is primarily to immobilize the prey and secondly to assist with the process of digestion.

Venom toxicity does not always correlate with the danger rating of a particular species. For example, the Inland Taipan (Oxyuranus microlepidotus) has the most toxic venom of all snakes in the world but there are several snakes that are considered more dangerous.

There are danger scores given to snakes which take into account five different factors which include:

  1. Venom toxicity
  2. Venom yield
  3. Fang length
  4. Temperament
  5. Bite frequency
There are several different types of toxins found in snake venom. Snake venom is usually a combination of several of these toxins. The main types of toxins are:
  • Neurotoxins – Paralysis of voluntary muscles
  • Haemotoxins – Destroy red blood cells
  • Coagulants – Cause blood clot in blood cells
  • Anticoagulants – Impede blood clotting
  • Cytotoxins – Destroy tissue
  • Hyaluronbidase activity – Increase the spreading factor of the venom

Reasons Why Snakes Bites

A snake will only bite an animal that is not a food item in an act of self defense. This means that if a person accidentally steps on a snake they may be bitten as the snake will assume it is being attacked. Not surprisingly the majority of snakebites occur when people try to catch or kill them.

INCIDENCE OF SNAKE BITES

There are around 8000 snakebites recorded in the USA every year.

DEATHS ATTRIBUTED TO SNAKE BITES

On average 12 people die from snakebite in the USA every year. The number of fatalities attributed to snakebite in the USA is relatively low because of the following reasons:

  1. Snakes are shy animals – Snakes will only bite as a last resort
  2. No venom injected –  Not all snakebites result in envenomation
  3. Public education – People generally know to treat snakes with respect
  4. First aid – Development of effective first aid procedure
  5. Medical technology – Development of effective antivenom

It is important to treat all snakebites seriously to prevent complications arising through incorrect identification.

Discouraging Snakes

Snakes are attracted to an area in pursuit of food and habitat. By decreasing the availability of these two variables it is possible to reduce the likelihood of snakes entering the vicinity around your house.

FOOD

  • Chicken coops and bird aviaries should be rodent-proof
  • All animal food should be stored airtight containers
  • Dog food and cat food should only be offered to pets for small periods of time each day

HABITAT

A well-maintained lawn free of refuse provides a poor habitat for snakes. It also allows good visibility which reduces the incidence of people accidentally stepping on a snake. Any material laying directly on the ground can provide habitat for snakes. This can include such things as timber, iron sheeting, grass clippings, and firewood. Additionally, retaining walls provide excellent habitat for snakes. The following precautionary measures can be taken to reduce available habitat for snakes:

  • The materials mentioned above should not be stored near the house for extended periods of time
  • Building materials and firewood piles should not be stored directly on the ground but raised at least 100mm off the ground on strips of timber

Some species specialize on feeding on frogs. Therefore, ponds and other water sources that provide frogs with habitat have the potential of attracting these species of snakes. For this reason, it is a good idea to situate ponds a sensible distance from the house.

Snake Identification

USA and Canada are home to a large number of different species of snakes. Many species are similar in appearance and are extremely difficult to differentiate from one another while some snakes display high variations in appearance within a particular species. For these reasons, experts rely on scale patterns to make a positive identification of a snake.

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DIFFERENCE BETWEEN SNAKES AND LIZARDS

The most common method for determining the difference between a snake and a lizard is the presence or absence of limbs. However, there are several species of lizards that have very small or no legs. The differences between snakes and legless lizards are:

  • Tongue – Snakes have forked tongues which they use to ‘taste’ the air for scent particles. All species of legless lizards have a fleshy tongue.
  • Eyes – Most species of lizards have moveable eyelids. Snakes have fixed transparent scales that cover their eyes which are known as the brille or spectacle.
  • External ear openings –  All species of legless lizards have external ear openings. Snakes do not have ears, and as a result are unable to hear airborne sound using an ear. Snakes are very sensitive to vibrations and actually have some remnant bones of the ear attached to the lower jawbone

Characteristics of Snakes

Like all groups of reptiles, snakes have the following characteristics:

  • Cold-blooded – Snakes are ectotherms, and unlike mammals, they do not rely on cellular metabolism to maintain their temperature. Instead, they obtain their heat from external sources, such as the sun. Some species of snakes can go up to 12 months without eating and as a result, can live in areas where food is not plentiful.
  • Scales – Snakes are covered in scales. Their scales work similarly to that of a raincoat, instead of not letting water in, scales don’t let water out. This prevents them from dehydrating and as a result enables them to colonize very arid regions such as deserts.
  • Sloughing – Snakes simultaneously shed their outer layer of skin intermittently, which is usually directly related to growth rate.
  • Sexual dimorphism – Female snakes and male snakes are very difficult to differentiate because all of their reproductive organs are internal.
  • Growth – Reptiles are the only group of vertebrates (animals with backbones) that continue to grow throughout their life.
  • Food – Snakes feed on a variety of prey including mammals, birds, reptiles, amphibians, fish and invertebrates. All food items are eaten whole.

Wyoming Snake Identification Guide (With Pictures & Charts)

Rubber Boa (Charina bottae)

Rubber Boa Charina bottae
Natalie McNear
Common NameRubber Boa
Scientific NameCharina bottae
FamilyBoas
Average Length83cm
VenomNon-venomous
ReproductionLive
Number of Offspring4

Racer (Coluber constrictor)

Racer Coluber constrictor
Andrew Hoffman
Common NameRacer
Scientific Name
Coluber constrictor
Family
Solid Toothed & Rear Fanged
Average Length191cm
VenomNon-venomous
ReproductionEggs
Number of Offspring14

Midget Faded Rattlesnake (Crotalus oreganus)

Midget Faded Rattlesnake Crotalus oreganus
Charles (Chuck) Peterson
Common NameMidget Faded Rattlesnake
Scientific NameCrotalus oreganus
FamilyPit Vipers
Average Length75cm
VenomExtremely Venomous
ReproductionLive
Number of Offspring5

Western Rattlesnake (Crotalus viridis)

Western Rattlesnake Crotalus viridis
Patrick Alexander
Common Name
Western Rattlesnake
Scientific NameCrotalus viridis
FamilyPit Vipers
Average Length163cm
VenomExtremely Venomous
ReproductionLive
Number of Offspring10

Hog-nose Snake (Heterodon nasicus)

Hog-nose Snake Heterodon nasicus
squamatologist
Common NameHog-nose Snake
Scientific NameHeterodon nasicus
FamilySolid Toothed & Rear Fanged
Average Length154cm
VenomNon-venomous
ReproductionEggs
Number of Offspring11

Gopher Snake (Pituophis catenifer)

Gopher Snake Pituophis catenifer
Wildlife Wanderer
Common NameGopher Snake
Scientific NamePituophis catenifer
FamilySolid Toothed & Rear Fanged
Average Length274cm
VenomNon-venomous
ReproductionEggs
Number of Offspring11

Red-bellied Snake (Storeria occipitomaculata)

Red-bellied Snake Storeria occipitomaculata
smashtonlee05
Common NameRed-bellied Snake
Scientific NameStoreria occipitomaculata
FamilySolid Toothed & Rear Fanged
Average Length41cm
VenomNon-venomous
ReproductionLive
Number of Offspring8

Plains Black-headed Snake (Tantilla nigriceps)

Plains Black-headed Snake Tantilla nigriceps
Andrew DuBois
Common NamePlains Black-headed Snake
Scientific NameTantilla nigriceps
FamilySolid Toothed & Rear Fanged
Average Length39cm
VenomMildly Venomous
ReproductionEggs
Number of Offspring2

Western Terrestrial Garter Snake (Thamnophis elegans)

Western Terrestrial Garter Snake Thamnophis elegans
Andrew Reding
Common NameWestern Terrestrial Garter Snake
Scientific NameThamnophis elegans
FamilySolid Toothed & Rear Fanged
Average Length109cm
VenomMildly Venomous
ReproductionLive
Number of Offspring