Why did God make snakes? l The majority of snakes eat rodents l Rats and mice carry disease and destroy millions of dollars worth of crops and grains each year. l One Texas Rat Snake will eat 40+ rats and mice per year. l More ecologically sound that using pesticides.
Venomous snakes of Texas Rattlesnakes Water moccasins Copperheads Coral snakes
Venomous snakes of Texas l 2 Families l Viperidae - Vipers Rattlesnakes Water moccasins Copperheads l Elapidae coral snakes
Venomous Snakes of Texas l 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
Rattlesnakes l Crotaline l Account for the majority of all poisonous snake bites l 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 l These are dangerous and strong snakes - DO NOT HANDLE
Rattlesnakes, cont. l 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
Agkistradon sp. l Copperheads are responsible for approximately 25% of venomous snake bites l Water Moccasins are responsible for approximately 10% of venomous snake bites l AAPCC has reported no deaths since 1983.
Agkistradon sp. l 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. l 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
Agkistradon sp., cont. l 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
Elapidae l Proteroglyphs - rigid front fangs, less than 1/8th inch in length l Coral snake l Same family as the cobras and most of the venomous snakes of Africa and Australia l Most active in the early morning and the late afternoon, found under piles of leaves or rocks
Coral Snakes l Probably less than 20 bites per year (61 bites reported to the AAPCC in 1998) l No deaths reported since antivenom has been available l Prior death rate was approximately 10% and cause of death was respiratory and cardiovascular failure
Coral snakes, cont. l Eat snakes, skinks and other lizards l Adults can reach 24 - 36 inches with the record being 47 3/4’s inches l Lay eggs l “Red on yellow kill a fellow, red on black venom lack”
Morbidity Rates l American Association of Poison Control Centers documented 7,000 reptile bites/year in North American in 1999 l 85% of the victims were treated in health care facilities l Up to 50% of bites can be “dry bites l An average of 5.5 deaths occur per year as a result of a snake bite - most are due to rattlesnake bites.
Snakebite statistics l 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 l 66% are by rattlesnakes, 25% by copperheads, 10% are by water moccasins and 1% by coral snakes l Est. 30,000 to 110,000 deaths worldwide
Snakebite statistics l No reported deaths from an Agkistradon bite in US since 1983 l No reported deaths from Coral snakes since antivenom has become available l Snakebite is most common in school age children, 5-19 year old males l Snakebites occur most frequently in the Southern US l The majority of snakebite occur between 9 a.m. and 9 p.m.
Snakebite statistics l 58% of victims were bitten on lower extremities, 38% on upper extremities l Most people are bitten on the right side of the body l Number one spot to be bitten is in your own yard l Most snake bites occur between April and October
Snakebite statistics l Geographic distribution of snakebites in the US number 1 state - North Carolina number 2 state - Arkansas number 3 state - Texas l 100% of patients bitten by a poisonous snake had one or more fang marks at the bite site
Snakebite statistics l 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 l 1-3 million animal bites in this country - 85% are from dogs, 10% from cats, 5% from rodents l 1% of DBW and 6% CBW require hospitalization l Dog attacks account for 10,000 hospitalizations annually, 10-20 reported deaths annually and most of these are young children
Animal bites l Cost in medical care estimated at $5-30 million/yr. l Dog and cat bites have a high risk of infection l Women more frequently bitten by cats and men by dogs l Peak incidence of dog bites is children 5-14 years of age
Snake venom l How envenomation occurs - the bite l What organ makes venom - modified saliva from the parotid salivary gland l Is all venom equal? NO l You are dealing with multiple poisonings, multiple systems are affected
Snake venom l 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 l Venom’s polypeptides damage endothelial cells and allow plasma to exude and blood to extravasate into the surrounding tissues - causing hypovolemic shock l Circulation of the venom throughout the body speeds the digestive process l Mojave rattler is an exception - they immobilize prey by neuromuscular blockade
To determine how serious a bite is: l age and size of the patient l depth, location and number of bites l duration of the bite l how much clothing was the victim wearing l maturity, type and size of the snake l condition of the fangs and venom sack l how angry or fearful was the snake at the time of the bite
Signs and Symptoms of a pit viper bite: l Immediate and severe burning pain and swelling around the fang marks l Purplish discoloration around the bite l Numbness and blistering around the bite l Nausea and vomiting l Tachycardia, hypotension, syncope, generalized paresis and diaphoresis l Fever and chills, dimmed vision, headache l Muscular twitching and convulsions
Snake venom l 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 l Coral snake envenomations can occur without visible fang marks (may appear as scratch marks) l Effects are primarily neurotoxic in nature and produce very few local tissue toxic effects l 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: l mild local swelling l paresthesias l nausea and vomiting l generalized paresis l dizziness, diplopia l dyspnea and diaphoresis l dysphagia and hypersalivation l ptosis, blurry vision, dysarthria l respiratory failure is the cause of death
Treatment of Snake Bite l Basics: Maintain life support - airway, breathing and circulation Limit the spread of the venom Transport the victim without delay l 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
Treatment of Snake Bite l Number one rule of treatment: “Primum non nocere” First, do no harm
Treatment of Snake Bite l Move the patient away from the snake l Have the patient lie down and stay quiet l 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) l Keep bitten extremity below heart level l Remove all rings, bracelets or other jewelry
Treatment of Snake Bite l Clean the wound gently with alcohol, soap and water or hydrogen peroxide l DO NOT apply ice - causes further vasoconstriction and ischemia in marginally perfused tissues l Apply a sling and wrap the limb with a ace bandage or stretch type of gauze (Kling®) - immobilize the limb l The application of a constricting band is controversial - if use - adjust repeatedly
Treatment of Snake Bite l 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
Treatment of Snake Bite l Most effective treatment is the administration of antivenom l Available from Wyeth Labs (1-610-688- 4400), derived from horse serum l For exotic snakes contact 1-718-430-6494 l Anaphylaxis (type I hypersensitivity) and serum sickness (type III) is a real concern
Venomous snakes l What snake is the most venomous? l Can snakes bite you underwater? l What snake has the longest fangs? l How do you avoid being bitten? l Pictures of various poisonous snakes
Black Widow Spider l red hour glass on the abdomen l only the female is dangerous l venom l “target lesion” l 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. l 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 l The female is about ½-inch long, l 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.
l 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. l 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.
Brown recluse spider l to identify the spider 3 pairs of eyes verses 4 pair “fiddle back spider” l “bulls eye” appearance lesion l clinical signs l 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 of treatment.
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.
l 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. l 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. l To further reduce spider entry from outside, insecticides can be applied as a "barrier treatment" around the base of the foundation.
Scorpions l Centruroides sp. blocks neuromuscular transmission causes hypertension venom is a neurotoxin no specific treatment toxic species not in Texas l 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 l The highest reported mortality rate is recorded in data from Mexico, with estimates as high as 1000 deaths/year. l 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.