:''Common names: Osage copperhead, central copperhead.Gloyd HK, Conant R. 1990. Snakes of the Agkistrodon Complex: A Monographic Review. Society for the Study of Amphibians and Reptiles. 614 pp. 52 plates. LCCN 89-50342. .'' ''Agkistrodon contortrix phaeogaster'' was formerly a

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

pit viper subspecies found in the central region of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. However, recent taxonomic changes do not recognizes the Osage copperhead (''A. c. phaeogaster'') as a valid taxon.

New Taxonomy

The Osage copperhead (''Agkistrodon contortrix phaeogaster'') was once classified as a subspecies of the copperhead (''

Agkistrodon contortrix The eastern copperhead (''Agkistrodon contortrix''), also known as the copperhead, is a species of venomous snake, a pit viper, endemic to eastern North America; it is a member of the subfamily Crotalinae in the family Viperidae. The eastern co ...

''). However, DNA based studies published in 2008 and 2015, revealed no significant genetic difference between the Osage copperhead (''Agkistrodon contortrix phaeogaster''), the southern copperhead, (''Agkistrodon contortrix contortrix''), and the northern copperhead (''Agkistrodon contortrix mokasen''). The three subspecies were synonymized and elevated to one species, with the oldest published name, ''Agkistrodon contortrix'', having priority. The resulting taxonomy does not recognizes the Osage copperhead (''Agkistrodon contortrix phaeogaster'') as a valid taxon.Guiher TJ, Burbrink FT (2008). ''Demographic and phylogeographic histories of two venomous North American snakes of the genus Agkistrodon.'' Molecular Phylogenetics and Evolution, 48: 543–553.Burbrink, Frank T. and Timothy J. Guiher. 2014. ''Considering gene flow when using coalescent methods to delimit lineages of North American pitvipers of the genus Agkistrodon.'
Zoological Journal of the Linnean Society, 173: 505–526
Several subsequent reviews and species accounts have followed and supported the revised taxonomy.Crother, B. I. ( editor). 2017. ''Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding, 8th. edition.'' SSAR Herpetological Circular 43, 1–102 pp. (page 59) Powell, Robert, Roger Conant, and Joseph T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, 4th ed. Houghton Mifflin Harcourt Publishing Co. New York. 494 pp. Uetz P, Freed P, Aguilar R, Hošek J (editors) (2021). The Reptile Database
Agkistrodon contortrix
(accessed 30 August 2021) Information on this snake can be found in the ''

'' article.

Description

Gloyd and Conant (1990) gives maximum total lengths of 990 to 723 mm for males and females, respectively, while mentioning that other sources give a maximum total length for this subspecies of 1,016 mm regardless of sex. The color pattern is similar to that of '' A. c. mokasen'', except that the dark bands are in sharper contrast to the lighter ground color, and with no smaller dark spots between them.Conant R. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Second Edition. First published in 1958. Houghton Mifflin Company Boston. 429 pp. 48 plates. (hc), (pb).

Geographic range

Found in the

in eastern

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to th ...

, extreme southeastern

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the sout ...

and a large part of

Missouri Missouri is a state in the Midwestern region of the United States. Ranking 21st in land area, it is bordered by eight states (tied for the most with Tennessee): Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas t ...

. The type locality given is "10 miles south of McLouth, Jefferson County, Kansas."

Venom

The venom of Agkistrodon contortrix phaeogaster is similar to the venoms produced by other species of the Agkistrodon genus. The exact ratio of toxins to each other varies among species and gender, as does the overall potency of the venom (the ratio of active toxins to other constituents of the venom). The venom is most potent between the late-spring and mid-summer months, this rise in toxicity commences 2–3 weeks prior to reaching peak toxicity. While the initial reduction of potency occurs over approximately one month, the snake's venom remains slightly more toxic throughout the late-summer months until beginning a slow descent to reach its original toxicity by mid-fall.

Danger to humans

The bite of the Osage copperhead is considered a medical emergency and the victim should be brought to a hospital immediately for the best prognosis (an ambulance should be called if the victim is alone, as driving is highly dangerous after an envenomation). The effects of the toxic venom present with a predictable course of symptoms until treatment is received. Immediate and severe pain, oozing of blood from the fang punctures, considerable edema,

epistaxis A nosebleed, also known as epistaxis, is bleeding from the nose. Blood can flow down into the stomach, and cause nausea and vomiting. In more severe cases, blood may come out of both nostrils. Rarely, bleeding may be so significant that low bl ...

, bleeding of the gums, marked

hematuria Hematuria or haematuria is defined as the presence of blood or red blood cells in the urine. “Gross hematuria” occurs when urine appears red, brown, or tea-colored due to the presence of blood. Hematuria may also be subtle and only detectable w ...

, general petechiae,

shock Shock may refer to: Common uses Collective noun *Shock, a historic commercial term for a group of 60, see English numerals#Special names * Stook, or shock of grain, stacked sheaves Healthcare * Shock (circulatory), circulatory medical emergen ...

renal failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

, and local necrosis. These effects are attributed to the various

haemotoxin Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells, disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term ''hemotoxin'' is to some degree a misnomer since toxins that damage ...

s and necrotoxins contained in the venom. Many other toxins are present in the venom in small quantities and are not clinically significant due to their extremely low concentrations.

Treatment

CroFab antivenin has been used successfully to treat Osage copperhead bites, although a lack of complete cross-tolerance requires careful administration and close supervision during the full course of treatment to ensure that the lowest effective dose is administered (a lower dose would not fully treat the envenomation, and a higher dose may be particularly dangerous to children, the elderly, and infirm adults). Not uncommonly, opiate/opioid narcotic

analgesics An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

(ex.

morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. T ...

fentanyl Fentanyl, also spelled fentanil, is a very potent synthetic opioid used as a pain medication. Together with other drugs, fentanyl is used for anesthesia. It is also used illicitly as a recreational drug, sometimes mixed with heroin, cocain ...

), muscle relaxerss (ex.

diazepam Diazepam, first marketed as Valium, is a medicine of the benzodiazepine family that acts as an anxiolytic. It is commonly used to treat a range of conditions, including anxiety, seizures, alcohol withdrawal syndrome, muscle spasms, insomnia, ...

tizanidine Tizanidine, sold under the brand name Zanaflex among others, is a medication that is used to treat muscle spasticity due to spinal cord injury or multiple sclerosis as well as spastic cerebral palsy. Effectiveness appears similar to baclofen ...

, orphenadrine), and

broad-spectrum antibiotic A broad-spectrum antibiotic is an antibiotic that acts on the two major bacterial groups, Gram-positive and Gram-negative, or any antibiotic that acts against a wide range of disease-causing bacteria. These medications are used when a bacterial ...

s are administered. A few days' supply of weaker analgesics and muscle relaxers may be prescribed for the patient to control pain after he or she returns home as the pain resolves completely within one to three days. Patients also receive a prescription for an intensive antibiotic therapy, which much be taken until the supplies are depleted, giving the drug enough time to fully treat any opportunistic infections resulting from the bite wounds or other transmission methods which the victim's weakened immune system cannot defend against. Failing to take the antibiotics until the prescription is depleted can cause the bacteria to "rebound" in a new form, possessing a greater resistance to antibiotics (

MRSA Methicillin-resistant ''Staphylococcus aureus'' (MRSA) is a group of Gram-positive bacteria that are genetically distinct from other strains of ''Staphylococcus aureus''. MRSA is responsible for several difficult-to-treat infections in humans. ...

developed through this process).

Antivenin availability

CroFab antivenin is effective in treating ''A. c. phaeogaster'' bites, but it may cause severe anaphylactic shock and should not be used in any individuals allergic to anything contained within the formula, unless the allergy is limited to nonlethal grievances such as rashes and itching. One other exception to this occurs when the envenomation is so severe that the victims' doctors determine this risk of death from envenomation outweighs the risk of inducing anaphylaxis in a critically ill patient. A major shortage of CroFab existed in the U.S., and the vials which are available are exorbitantly priced, leading many doctors to negate the use of the antivenin in many patients whose bite resulted in extreme suffering, but does not present any life-threatening symptoms (in these situations, palliative care and symptomatic/supportive treatment approaches are used, instead).

References

External links

* {{Taxonbar, from=Q4692715 contortrix phaeogaster Fauna of the Plains-Midwest (United States)