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Centruroides gracilis
General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid , Antivenoms
Centruroides gracilis (Colombian female, Honduran male)  [ Original photo copyright © Eric Ythier ]
Family: Buthidae
Genus: Centruroides
Species: gracilis
Common Names
Slender brown scorpion , Florida bark scorpion
North America + Central America + South America
Colombia, Cuba, Guatemala, Honduras, Mexico, Panama, United States of America, Venezuela
Taxonomy and Biology
Adult Length ( mm ): 75 mm
Colouration is variable over the range including : Entire body dark brown to blackish with reddish black pedipalp hands and grey pectines. Most common : Carapace, tergites and metasomal segments I to IV are pale to medium brown or reddish brown with metasomal segment V and telson darker, with or without a yellowish median stripe on tergites. Pedipalps are pale to medium brown or reddish brown with fingers darker brown or darker reddish brown when compared to manus. Ventral surface and sternites are pale yellowish brown or pale brown. Legs are yellowish brown, brown or reddish brown and usually paler than body.
General: Venom Neurotoxins
Excitatory neurotoxins; sodium & potassium channel toxins.
General: Venom Myotoxins
Not present
General: Venom Procoagulants
Not present
General: Venom Anticoagulants
Not present
General: Venom Haemorrhagins
Not present
General: Venom Nephrotoxins
Not present
General: Venom Cardiotoxins
Excitatory toxins release catecholamines, causing adrenergic cardiac effects.
General: Venom Necrotoxins
Not present
General: Venom Other
Clinical Effects
General: Dangerousness
Severe envenoming possible, potentially lethal
General: Rate of Envenoming: Unknown but likely to be low
General: Untreated Lethality Rate: 1-10%
General: Local Effects
Local pain, redness, pruritis, sensory change, swelling
General: Local Necrosis
Does not occur, based on current clinical evidence
General: General Systemic Effects
Not always present, but may include nausea, vomiting, sweating, piloerection, diarrhoea, difficulty breathing, tachy- or bradycardia, fever, hyperexcitability, hypertension, shock, convulsions, coma.
General: Myotoxicity
Does not occur, based on current clinical evidence
General: Coagulopathy & Haemorrhages
Does not occur, based on current clinical evidence
General: Renal Damage
Does not occur, based on current clinical evidence
General: Cardiotoxicity
Cardiac effects are those associated with catecholamine release and can include cardiac arrhythmias, heart failure, pulmonary oedema, tachycardia or bradycardia, hyper- or hypotension.
General: Other
Massive fluid loss from sweating and from the gut (vomiting & diarrhoea) may cause circulatory shock.
First Aid
Description: First aid for scorpion stings (in areas where potentially dangerous species may be found)
1. After ensuring the patient and onlookers are not at risk of further scorpion stings, the victim should be reassured and persuaded to lie down and remain still. Some may be terrified, fearing sudden death and, in this mood, they may behave irrationally or even hysterically, a situation made worse by the intense pain often suffered. The basis for reassurance is the fact that most scorpion stings prove non-lethal and the effectiveness of modern medical treatment.
2. The sting 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. Though unproven, there is anecdotal evidence suggesting the application of a cold pack to the sting area may reduce pain. At least in Mexico, there is also anecdotal evidence suggesting local suction may be beneficial.
3. All rings or other jewellery on the bitten limb, especially on fingers, should be removed, as they may act as tourniquets if swelling 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 scorpion has been killed it should be brought with the patient for identification.
9. The scorpion sting 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, 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. The role of suction by mouth, vacuum pump or syringe, combined incision and suction ("venom-ex" apparatus) is uncertain.

Treatment Summary
Stings by at least some Centruroides scorpions can cause severe, even lethal envenoming. All cases require urgent assessment and if envenoming is severe, consideration of early IV antivenom (where available - particularly in Mexico; not readily available in the US). Supportive care may also be indicated.
Key Diagnostic Features
Immediate local pain, redness, only mild swelling, but local hyperaesthesia or parasthesia, pruritis. Systemic features of catecholamine storm; sweating, abdominal pain, vomiting, diarrhoea, pulmonary oedema.
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.
Antivenom Therapy
Antivenoms only available for a few Centruroides species, but may be effective (not proven) across all members of Genus. Antivenom, if given early IV, is important in treatment, especially in children.
1. Antivenom Code: IAmIBM01
Antivenom Name: Suero Antialacran : Alacramyn
Manufacturer: Instituto Bioclon
Phone: ++56-65-41-11
Address: Calzada de Tlalpan No. 4687
Toriello Guerra
C.P. 14050
Mexico, D.F.,
Country: Mexico
Centruroides gracilis (Colombian female, Honduran male) [ Original photo copyright © Eric Ythier ]
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Centruroides gracilis female (Colombia) [ Original photo copyright © Eric Ythier ]
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Centruroides gracilis [ Original photo copyright © Dr Wolfgang Wuster ]
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Centruroides gracilis [ Original photo copyright © Jan Ove Rein]
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Centruroides gracilis (Colombian female, Honduran male) [ Original photo copyright © Eric Ythier ]
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