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![Sistrurus miliarius ( Southeastern Pygmy Rattlesnake ) subsp. barbouri [ Original photo copyright © Dr Julian White ]](images/snakes/SNP03421.jpg)
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Family: Viperidae
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Subfamily: Crotalinae
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Genus: Sistrurus
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Species: miliarius
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Subspecies: barbouri
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Common Names
( subsp. barbouri ) Southeastern Pygmy Rattlesnake , Dusky Pygmy Rattlesnake
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Region
North America
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Countries
United States of America
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Taxonomy and Biology
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Adult Length: 0.45 m
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General Shape
Small in length, tapered and cylindrical bodied snake with a moderately long and slender tail terminating in a tiny, segmented rattle. Can grow to a maximum of about 0.79 metres. Head is broad and distinct from narrow neck. Canthus rostralis is sharp. Eyes are small to medium in size with vertically elliptical pupils. Dorsal scales are keeled.
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Habitat
Found mainly in swamp, marsh and wooded floodplains.
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Habits
Diurnal and terrestrial snake.
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Prey
Feeds mainly on small rodents, frogs, large insects and spiders.
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Venom
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General: Venom Neurotoxins
Not present
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General: Venom Myotoxins
Unknown
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General: Venom Procoagulants
Unknown
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General: Venom Anticoagulants
Unknown
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General: Venom Haemorrhagins
Present but not defined
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General: Venom Nephrotoxins
Not present
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General: Venom Cardiotoxins
Not present
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General: Venom Necrotoxins
Unknown
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General: Venom Other
May include; Lectins; Nerve growth factors; Phospholipase inhibitors; Proteinase inhibitors; Complement inactivators; Biogenic amines; Carbohydrates; Lipids; Nucleosides & nucleotides
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Clinical Effects
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General: Dangerousness
Mild envenoming only, not likely to prove lethal
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General: Rate of Envenoming: Unknown but likely to be low
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General: Untreated Lethality Rate: Unlikely to prove lethal
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General: Local Effects
Local pain & swelling
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General: Local Necrosis
Potentially may occur
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General: General Systemic Effects
General systemic effects unlikely
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General: Neurotoxic Paralysis
Unlikely to occur
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General: Myotoxicity
Not likely to occur
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General: Coagulopathy & Haemorrhages
Some evidence of coagulopathy; some bleeding possible due to haemorrhagins.
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General: Renal Damage
Does not occur, based on current clinical evidence
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General: Cardiotoxicity
Does not occur, based on current clinical evidence
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General: Other
Not likely to occur
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First Aid
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Description: First aid for bites by Viperid snakes likely to cause significant local injury at the bite site (see listing in Comments section).
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Details
1. After ensuring the patient and onlookers have moved out of range of further strikes by the snake, the bitten person should be reassured and persuaded to lie down and remain still. Many will be terrified, fearing sudden death and, in this mood, they may behave irrationally or even hysterically. The basis for reassurance is the fact that many venomous bites do not result in envenoming, the relatively slow progression to severe envenoming (hours following elapid bites, days following viper bites) and the effectiveness of modern medical treatment.
2. The bite wound should not be tampered with in any way. Wiping it once with a damp cloth to remove surface venom is unlikely to do much harm (or good) but the wound must not be massaged.
3. All rings or other jewellery on the bitten limb, especially on fingers, should be removed, as they may act as tourniquets if oedema develops.
4. The bitten limb should be immobilised as effectively as possible using an extemporised splint or sling; if available, crepe bandaging of the splinted limb is an effective form of immobilisation.
5. If there is any impairment of vital functions, such as problems with respiration, airway, circulation, heart function, these must be supported as a priority. In particular, for bites causing flaccid paralysis, including respiratory paralysis, both airway and respiration may be impaired, requiring urgent and prolonged treatment, which may include the mouth to mask (mouth to mouth) technique of expired air transfer. Seek urgent medical attention.
6. Do not use Tourniquets, cut, suck or scarify the wound or apply chemicals or electric shock.
7. Avoid peroral intake, absolutely no alcohol. No sedatives outside hospital. If there will be considerable delay before reaching medical aid, measured in several hours to days, then give clear fluids by mouth to prevent dehydration.
8. If the offending snake has been killed it should be brought with the patient for identification (only relevant in areas where there are more than one naturally occurring venomous snake species), but be careful to avoid touching the head, as even a dead snake can envenom. No attempt should be made to pursue the snake into the undergrowth as this will risk further bites.
9. The snakebite victim should be transported as quickly and as passively as possible to the nearest place where they can be seen by a medically-trained person (health station, dispensary, clinic or hospital). The bitten limb must not be exercised as muscular contraction will promote systemic absorption of venom. If no motor vehicle or boat is available, the patient can be carried on a stretcher or hurdle, on the pillion or crossbar of a bicycle or on someone's back.
10. Most traditional, and many of the more recently fashionable, first aid measures are useless and potentially dangerous. These include local cauterization, incision, excision, amputation, suction by mouth, vacuum pump or syringe, combined incision and suction ("venom-ex" apparatus), injection or instillation of compounds such as potassium permanganate, phenol (carbolic soap) and trypsin, application of electric shocks or ice (cryotherapy), use of traditional herbal, folk and other remedies including the ingestion of emetic plant products and parts of the snake, multiple incisions, tattooing and so on.
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Treatment
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Treatment Summary
Bites may cause mild to moderate, rarely severe local effects, non-specific general effects. Admit & observe all cases. Only more severe cases require antivenom. Good wound care important; avoid fasciotomies unless absolutely indicated. Look for shock secondary to fluid shifts into bitten limb & manage appropriately.
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Key Diagnostic Features
Local pain, swelling, blistering, rarely necrosis
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General Approach to Management
All cases should be treated as urgent & potentially lethal. Rapid assessment & commencement of treatment including appropriate antivenom (if indicated & available) is mandatory. Admit all cases.
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Antivenom Therapy
Antivenom is the key treatment for systemic envenoming. Multiple doses may be required.
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| 1. Antivenom Code: SAmPRO01
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Antivenom Name: Polyvalent crotalid antivenom ( CroFab ), Ovine, Fab
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Manufacturer: Protherics Inc. (US)
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Phone: ++1-615-327-1027
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Address: 5214 Maryland Way
Suite 405
Brentwood
Tennessee 37027
USA
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Country: U.S.A.
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| 2. Antivenom Code: SAmIBM06
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Antivenom Name: Antivipmyn
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Manufacturer: Instituto Bioclon
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Phone: ++56-65-41-11
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Address: Calzada de Tlalpan No. 4687
Toriello Guerra
C.P. 14050
Mexico, D.F.,
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Country: Mexico
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