“spiders and snakes and things that slither in the grass”

“Spiders and Snakesand things that slither in

the grass”

This presentation is designed to give an overview of the venomous snakes and spiders commonly

encountered in Texas. It is not all inclusive. Treatments listed are

those most widely accepted at the time of publication.

© 1999, Gene F. Giggleman, DVM

Why did God make snakes?

The majority of snakes eat rodents Rats and mice carry disease and

destroy millions of dollars worth of crops and grains each year.

One Texas Rat Snake will eat 40+ rats and mice per year.

More ecologically sound that using pesticides.

Venomous snakes of Texas

RattlesnakesWater moccasins

CopperheadsCoral snakes

Venomous snakes of Texas

2 Families Viperidae - Vipers

•Rattlesnakes•Water moccasins•Copperheads

Elapidae•coral snakes

Venomous Snakes of Texas

Vipers (Viperidae) • solenoglyphs - hinged front fangs• strike prey and the search for it• heat pits on maxillae - “pit vipers” heat

sensing pit between nostril and eye• slit pupils• account for the majority of deaths• have live young

Heat pits and slit pupil

Rattlesnakes

Crotaline Account for the majority of all poisonous snake

bites Have a “rattle” on the tail - the number of

rattles reflects the number of times the snake has shed (usually 4x/year), serves as a warning but do not have to rattle before they strike

These are dangerous and strong snakes - DO NOT HANDLE

Rattlesnakes, cont.

Western diamondback rattlesnake - Crotalus atrox - atrox means frightful or grim• largest, most widespread and statistically

most dangerous (hazardous) serpent in the state

• venom contains 17% neurotoxically active peptides, 30% tissue digestive proteases and 53% blood targeted toxic enzymes

Rattlesnakes, cont.

• Western diamondback, cont.•found mostly in the western 2/3’s of the

state, prefer limestone and cedar habitats

•adults average 3-4 feet in length•diet is mostly small mammals•follow structured seasonal patterns, with

communal over wintering dens

Western Diamond Back

Western Diamondback

Agkistradon sp.

Copperheads are responsible for approximately 25% of venomous snake bites

Water Moccasins are responsible for approximately 10% of venomous snake bites

AAPCC has reported no deaths since 1983.

Agkistradon sp.

Water moccasin - Agkistradon picivours leukostoma (means forward fang fish eater with a white mouth)• AKA cotton mouth or stump tail• state record is just over 5 feet in length,

most are 20 -30 inches in length• like woodland or grasslands near water

Agkistradon sp., cont.

Water moccasin, cont.• eat frogs, fish, mammals, water birds, and

other snakes• less agile than water snakes, will hold their

ground and vibrate their tails when disturbed (other water snakes will not do this)

• usually swims with its entire body out of the water

Cottonmouth Water Moccasin

Water Moccasin

Immature Water Moccasin

Diamondback water snake

Yellow bellywater snake

Green water snake

Broad bandedwater snake

Agkistradon sp., cont.

Copperhead - Agkistradon contortrix • AKA land moccasin, chunkhead, highland

moccasin, white oak, pilot.• adults measure 18 - 30 inches• commonly found around human

habitations, prefer sandstone type habitats, diet is mostly mice

Copperhead

Copperheads, babies

Copperhead

Elapidae

Proteroglyphs - rigid front fangs, less than 1/8th inch in length

Coral snake Same family as the cobras and most of the

venomous snakes of Africa and Australia Most active in the early morning and the late

afternoon, found under piles of leaves or rocks

Coral Snakes

Probably less than 20 bites per year (61 bites reported to the AAPCC in 1998)

No deaths reported since antivenom has been available

Prior death rate was approximately 10% and cause of death was respiratory and cardiovascular failure

Coral snakes, cont.

Eat snakes, skinks and other lizards Adults can reach 24 - 36 inches with the

record being 47 3/4’s inches Lay eggs “Red on yellow kill a fellow, red on black

venom lack”

Coral Snake

Milk snake

Coral snake

Would you pick up this snake ?

Morbidity Rates

American Association of Poison Control Centers documented 7,000 reptile bites/year in North American in 1999

85% of the victims were treated in health care facilities

Up to 50% of bites can be “dry bites An average of 5.5 deaths occur per year as a

result of a snake bite - most are due to rattlesnake bites.

Snakebite statistics

Other sources report about 45,000 snake bites/year in USA, of those 7,000 are by poisonous snakes with 5-10 deaths/year from snakebite

66% are by rattlesnakes, 25% by copperheads, 10% are by water moccasins and 1% by coral snakes

Est. 30,000 to 110,000 deaths worldwide


No reported deaths from an Agkistradon bite in US since 1983

No reported deaths from Coral snakes since antivenom has become available

Snakebite is most common in school age children, 5-19 year old males

Snakebites occur most frequently in the Southern US

The majority of snakebite occur between 9 a.m. and 9 p.m.


58% of victims were bitten on lower extremities, 38% on upper extremities

Most people are bitten on the right side of the body

Number one spot to be bitten is in your own yard

Most snake bites occur between April and October


Geographic distribution of snakebites in the US• number 1 state - North Carolina• number 2 state - Arkansas• number 3 state - Texas

100% of patients bitten by a poisonous snake had one or more fang marks at the bite site


The second most consistent sign of snake bite was edema, third was weakness and fourth was pain (pain is almost always present with crotalid bites)

Animal bites

1-3 million animal bites in this country - 85% are from dogs, 10% from cats , 5% from rodents

1% of DBW and 6% CBW require hospitalization

Dog attacks account for 10,000 hospitalizations annually, 10-20 reported deaths annually and most of these are young children

Animal bites

Cost in medical care estimated at $5-30 million/yr.

Dog and cat bites have a high risk of infection

Women more frequently bitten by cats and men by dogs

Peak incidence of dog bites is children 5-14 years of age

Snake venom

How envenomation occurs - the bite What organ makes venom - modified

saliva from the parotid salivary gland Is all venom equal? NO You are dealing with multiple

poisonings, multiple systems are affected

Snake venom

Properties of crotalid snake venom• 70% water by weight, dry weight is 90%

proteins• main function is immobilization, death and

predigestion of the prey• Immobilization is achieved by causing

hypovolemic shock• digestion is achieved by numerous

proteolvtic enzymes

Snake venom

Venom’s polypeptides damage endothelial cells and allow plasma to exude and blood to extravasate into the surrounding tissues - causing hypovolemic shock

Circulation of the venom throughout the body speeds the digestive process

Mojave rattler is an exception - they immobilize prey by neuromuscular blockade

To determine how serious a bite is:

age and size of the patient depth, location and number of bites duration of the bite how much clothing was the victim wearing maturity, type and size of the snake condition of the fangs and venom sack how angry or fearful was the snake at the time

of the bite

Signs and Symptoms of a pit viper bite:

Immediate and severe burning pain and swelling around the fang marks

Purplish discoloration around the bite Numbness and blistering around the bite Nausea and vomiting Tachycardia, hypotension, syncope,

generalized paresis and diaphoresis Fever and chills, dimmed vision, headache Muscular twitching and convulsions

Snake venom

Properties of Elapidae venom:• contains a complex mixture of polypeptides,

cholinesterase• Binds postsynaptically at the neuromuscular

junction producing a nondepolarizing blockade of cholinergic receptors

• very little to no enzymatic action• onset of signs and symptoms may be

delayed up to several hours

Snake venom

Coral snake envenomations can occur without visible fang marks (may appear as scratch marks)

Effects are primarily neurotoxic in nature and produce very few local tissue toxic effects

Very toxic snakes, a large coral snake may store up to 5 lethal doses of venom in its venom glands

Signs and Symptoms of a coral snake bite:

mild local swelling paresthesias nausea and vomiting generalized paresis dizziness, diplopia dyspnea and diaphoresis dysphagia and hypersalivation ptosis, blurry vision, dysarthria respiratory failure is the cause of death

Snakebite victim

Treatment of Snake Bite

Basics:• Maintain life support - airway, breathing

and circulation• Limit the spread of the venom• Transport the victim without delay

There is no statistical difference in the clinical course between patients who did and did not receive first aid prior to coming to the hospital for treatment


Number one rule of treatment:“Primum non nocere”

First, do no harm


Move the patient away from the snake Have the patient lie down and stay quiet Cut and suck methods are essentially

useless (you can get at best 6-10% of the venom and most patients do more harm than good)

Keep bitten extremity below heart level Remove all rings, bracelets or other jewelry


Clean the wound gently with alcohol, soap and water or hydrogen peroxide

DO NOT apply ice - causes further vasoconstriction and ischemia in marginally perfused tissues

Apply a sling and wrap the limb with a ace bandage or stretch type of gauze (Kling®) - immobilize the limb

The application of a constricting band is controversial - if use - adjust repeatedly


Do Nots:• Do not incise the fang marks• Do not use oral suction• Do not apply ice• Do not give alcohol or NSAID’s• Do not apply a tourniquet• Do not use electric shock gun


Most effective treatment is the administration of antivenom

Available from Wyeth Labs (1-610-688-4400), derived from horse serum

For exotic snakes contact 1-718-430-6494 Anaphylaxis (type I hypersensitivity) and

serum sickness (type III) is a real concern

Venomous snakes

What snake is the most venomous? Can snakes bite you underwater? What snake has the longest fangs? How do you avoid being bitten? Pictures of various poisonous snakes

The Taipan

Black Mamba

Green Mamba

Mojave Rattlesnake

Mojave rattlesnake

Gaboon viper, the

longestfangs

The heaviest snake,Anaconda

The longest snake

Reticulated python

Non Venomous Snakes

Of Texas

Eastern Coachwhip snake

Eastern Hognose snake

Texas rat snake

Speckled King Snake

Desert Kingsnake

Texas Bull Snake

Spiders

Black Widow Spider

red hour glass on the abdomen only the female is dangerous venom “target lesion” treatment

Black Widow Spider

Approximately 2500 widow spider bites were reported to the AAPCC in 1999, although this figure is probably conservative because of underreporting.

In the U.S., an average of 4 deaths per year are reported to occur as a result of spider bites. However, no deaths caused by widow spider envenomation have been reported to the AAPCC since its first annual report in 1983

Black Widow Spider

The female is about ½-inch long, shiny black and usually has a red

hourglass mark on the underside of the abdomen. In some varieties the hourglass mark may be reduced to two separate spots.

•Spiderlings and male spiders are smaller than the females and have several red dots on the abdomen’s upper side.

•Widow spiders belong to the cobweb spider family and spin loosely organized trap webs. The webs are usually found under objects such as rocks and ground trash or under an overhanging embankment.

Black widow spiders are not as common in homes as the brown recluse. When found in homes, they are usually under appliances or heavy furniture and not out in the open like other cobweb spiders.

Black widow spiders are timid, however, and will only bite in response to being injured. People are usually bitten when they reach under furniture or lift objects under which a spider is hiding.

•Black widow venom is a nerve toxin and its effects are rapid. Clinically see

• Painful rigidity of the abdomen • Tightness of the chest. • Increased Blood pressure• Increased body temperature• sweating•localized swelling• nausea •In about 5% of the bite cases, the victim may go into convulsions in 14 to 32 hours and die if not given medical attention.

•First aid for black widow spider bites involves cleaning the wound and applying ice packs to slow absorption of venom. Victims should seek medical attention promptly. Most black widow spider envenomizations respond to intravenous administrations of calcium gluconate or calcium salts. An antivenin is also available for severe cases.

Black widow

Brown recluse spider

to identify the spider• 3 pairs of eyes verses 4 pair• “fiddle back spider”

“bulls eye” appearance lesion clinical signs treatment

•The brown recluse is about the size of a black widow but it is not so readily distinguished from many other spiders. It ranges from a dark cream color to dark brown. The abdomen is darker than the rest of the body. It has a violin- shaped, dark mark in top of the leg-bearing section of the body and therefore is sometimes called the “fiddler or violin” spider. •Brown recluse spiders also have three pairs of eyes rather than four pairs for most other spiders.

The brown recluse roams at night seeking its prey. During the day, It hides in dark niches and corners, where it may spin a poorly organized web. It is shy and will try to run from a threatening situation but will bite if cornered.

People are sometimes bitten while they are asleep because they roll onto a brown recluse while it is hunting in the bed. More often the victim is bitten while putting on a shoe or piece of clothing which a spider has selected for its daytime hiding place.

•The bite of the brown recluse is usually painless until three to eight hours later when it may become red, swollen, and tender (bull’s eye lesion). Later, the red area around the bite may develop into an ulcerous sore from one half to ten inches in diameter. Healing often requires a month or longer, and the victim may be left with a deep scar.

Prompt medical attention can reduce the extent of ulceration and alleviate other complications that may develop. In rare cases, the bite can produce a severe systematic reaction resulting in death.

•Persons bitten by a spider which they think is a brown recluse should try to collect the specimen and bring it to a qualified individual for identification.

•Positive identification by an expert will help the physician decide on the appropriate course oftreatment.

Brown recluse spider

Control:

Eliminating an infestation of brown recluse or black widow spiders involves two basic principles:

(1) altering the environment in and around a building to make it less attractive to spiders; and

(2) finding and destroying as many spiders as possible.

•The following measures can be used to control all spiders:

•Routine, thorough house cleaning is the best way to eliminate spiders and discourage their return. A vacuum cleaner or broom effectively removes spiders, webs, and egg sacs. •Spiders prefer quiet, undisturbed areas such as closets, garages, basements, and attics. Reducing clutter in these areas makes them less attractive to spiders.•Install tight-fitting window screens and door sweeps to exclude spiders and other insects. Inspect and clean behind outdoor window shutters.

Large numbers of spiders often congregate outdoors around the perimeter of structures. Migration indoors can be reduced by moving firewood, building materials, and debris away from the foundation. Shrubs, vines and tree limbs should be clipped back from the side of the building.

Consider installing yellow or sodium vapor light bulbs at outside entrances. These lights are less attractive than incandescent bulbs to night-flying insects which, in turn, attract spiders.

To further reduce spider entry from outside, insecticides can be applied as a "barrier treatment" around the base of the foundation.

Scorpions

Centruroides sp.• blocks neuromuscular transmission• causes hypertension• venom is a neurotoxin• no specific treatment• toxic species not in Texas

Texas scorpions produce a bite that is painful, red and swollen

Scorpions

In the US: In 1999, a total of 13,642 scorpion envenomations were reported to the AAPCC. However, because of underreporting, this is probably an underestimation of the true number of stings.

Scorpions

The highest reported mortality rate is recorded in data from Mexico, with estimates as high as 1000 deaths/year.

In the United States, 4 deaths were reported in an 11-year period according to one source (Langley, 1997). However, no deaths were reported to the AAPCC from 1983 to 1999. Only one death from the Arizona bark scorpion (C exilicauda) has been reported since 1964.

The Bark scorpion

Bark scorpion

“spiders and snakes and things that slither in the grass”

Documents

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majority of snakes

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