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Atropoides mexicanus
General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid , Antivenoms
Atropoides mexicanus ( Jumping Pit Viper )  [ Original photo copyright © Dr Julian White ]
Family: Viperidae
Subfamily: Crotalinae
Genus: Atropoides
Species: mexicanus
Common Names
Jumping Pit Viper , Mexican Jumping Pit Viper , Central American Jumping Pitviper
Local Names
Bajequilla , Bolpach , Brazo de Piedra , Cabeza de Sapo , Chehpat , Chinchintor , Dormilon , Dormilona , Jumping Tommygoff , Mano de Metate , Mano de Piedra , Mococh , Najak Tzajin , Nauyaca , Ochcan , Otooy , Patoca , Pawangu Tsany , Saltadora , Sok Sok , Tamaga , Tamagas , Timbo , Toboba , Toboba Chinga , Tunco , Xalpate
Central America
Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama
Taxonomy and Biology
Adult Length: 0.50 m
General Shape
Small in length, rugose appearance, very stout bodied snake with a short tail that terminates with a moderately long tail spine. Can grow to a maximum of about 0.98 metres. Head is broad and triangular when viewed from above and distinct from neck. Eyes are moderately small in size with vertically elliptical pupils. Snout is rounded when viewed from above and not elevated when viewed laterally. Dorsal scales have prominent high keeling, particularly on the vertebral and paravertebral scale rows.
Elevations up to about 1600 metres in tropical rainforest, subtropical wet forest and lower montane cloud forest.
Terrestrial and mainly a diurnal snake in upland populations but active by day and night in lowland populations.
Juveniles feed mainly on skinks and large insects ( mainly crickets and grasshoppers. Adults feed mainly on small mammals ( mostly rodents ) and lizards.
Species Map
Small (Approx 20k) version
General: Venom Neurotoxins
Probably not present
General: Venom Myotoxins
Possibly present but not clinically significant
General: Venom Procoagulants
Possibly present
General: Venom Anticoagulants
Probably not present
General: Venom Haemorrhagins
Possibly present but not clinically significant
General: Venom Nephrotoxins
Probably not present
General: Venom Cardiotoxins
Probably not present
General: Venom Necrotoxins
Probably not present
General: Venom Other
Clinical Effects
General: Dangerousness
Unknown, but potentially lethal envenoming, though unlikely, cannot be excluded.
General: Rate of Envenoming: Unknown but likely to be moderate
General: Untreated Lethality Rate: Unknown but may cause major envenoming
General: Local Effects
Insufficient clinical reports to know, but possibly mild to moderate local effects; pain, swelling, bruising, blistering, possibly necrosis
General: Local Necrosis
Potentially may occur, but uncommon to rare
General: General Systemic Effects
Insufficient clinical reports to know, but might develop systemic symptoms in severe cases; headache, nausea, vomiting, abdominal pain, collapse
General: Neurotoxic Paralysis
Insufficient clinical reports to know, but unlikely to occur
General: Myotoxicity
Insufficient clinical reports to know, but unlikely to occur
General: Coagulopathy & Haemorrhages
Insufficient clinical reports to know, but potentially may occur in moderate to severe cases
General: Renal Damage
Insufficient clinical reports to know, but unlikely to occur
General: Cardiotoxicity
Insufficient clinical reports to know, but unlikely to occur
General: Other
Insufficient clinical reports to know
First Aid
Description: First aid for bites by Viperid snakes likely to cause significant local injury at the bite site (see listing in Comments section).
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.
Treatment Summary
The minor pit vipers of South & Central America are poorly defined clinically. They appear likely to cause mostly mild to moderate local effects only, but potentially might cause more severe local effects and systemic effects, most likely coagulopathy & bleeding. There are no specific antivenoms, but most are covered by one or more regional pit viper antivenoms, which should be used for moderate to severe envenoming. In less severe cases treatment is symptomatic.
Key Diagnostic Features
Local pain, swelling ± coagulopathy & haemorrhage in severe cases
General Approach to Management
It is possible that most cases will be minor, but some cases may be more severe, requiring admission and treatment, so assess carefully before discharge.
Antivenom Therapy
Only antivenoms available are for related species, but should be used for significant envenoming
1. Antivenom Code: SAmICP01
Antivenom Name: Polyvalent Antivenom
Manufacturer: Instituto Clodomiro Picado
Phone: ++506-2511-7888
Address: Contiguo a la plaza de deportes,
Dulce Nombre de Coronado.
San José
Costa Rica
Country: Costa Rica
2. Antivenom Code: SAmIBB03
Antivenom Name: Soro antibotropico-laquetico
Manufacturer: Instituto Butantan
Phone: +55-11-3726-7222
Address: Av. Vital Brasil, 1500 Butanta
Sao Paulo - SP
Country: Brazil
3. Antivenom Code: SAmIBB05
Antivenom Name: Soro botropico
Manufacturer: Instituto Butantan
Phone: +55-11-3726-7222
Address: Av. Vital Brasil, 1500 Butanta
Sao Paulo - SP
Country: Brazil
4. Antivenom Code: SAmIBB07
Antivenom Name: Soro antibotropico-crotalico
Manufacturer: Instituto Butantan
Phone: +55-11-3726-7222
Address: Av. Vital Brasil, 1500 Butanta
Sao Paulo - SP
Country: Brazil
5. Antivenom Code: SAmIBM06
Antivenom Name: Antivipmyn
Manufacturer: Instituto Bioclon
Phone: ++56-65-41-11
Address: Calzada de Tlalpan No. 4687
Toriello Guerra
C.P. 14050
Mexico, D.F.,
Country: Mexico
Atropoides mexicanus ( Jumping Pit Viper ) [ Original photo copyright © Dr Julian White ]
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