{{Short description|Toxins that destroy red blood cells}} {{Medref|date=November 2021}} '''Haemotoxins''', '''hemotoxins''' or '''hematotoxins''' are [[toxin]]s that destroy [[red blood cell]]s, disrupt [[blood]] [[thrombus|clotting]], and/or cause [[Organ (anatomy)|organ]] degeneration and generalized [[Biological tissue|tissue]] damage. The term ''haemotoxin'' is to some degree a [[misnomer]] since toxins that damage the blood also damage other tissues. Injury from a haemotoxic agent is often very painful and can cause permanent damage and in severe cases death. Loss of an affected limb is possible even with prompt treatment.
Haemotoxins are frequently employed by [[venom (poison)|venomous]] animals, including snakes ([[Viperidae|viper]]s and [[Crotalinae|pit viper]]s) and spiders ([[brown recluse]]). Animal venoms contain [[enzyme]]s and other [[protein]]s that are haemotoxic or [[neurotoxin|neurotoxic]] or occasionally both (as in the [[Crotalus scutulatus|Mojave rattlesnake]], the [[Gloydius blomhoffii|Japanese mamushi]],<ref name=igari>{{cite journal|pmid=20297733 |script-title=ja:症例報告 マムシ咬傷により複視・眼瞼下垂をきたした1例 |trans-title=Binocular diplopia and ptosis due to snakebite (Agkistrodon blomhoffi "mamushi")--a case report |language=Japanese |url=http://medicalfinder.jp/ejournal/openUrl.do?issn=18816096&genre=article&volume=62&issue=3&spage=273 |archive-url=https://archive.today/20130905193530/http://medicalfinder.jp/ejournal/openUrl.do?issn=18816096&genre=article&volume=62&issue=3&spage=273 |url-status=dead |archive-date=2013-09-05 |year=2010 |last1=Igari |first1=R |last2=Iseki |first2=K |last3=Abe |first3=S |last4=Syoji |first4=M |last5=Sato |first5=M |last6=Shimomura |first6=K |last7=Hayashida |first7=A |last8=Sugiura |first8=A |last9=Iwashita |first9=Y |last10=Midorikawa |first10=S |volume=62 |issue=3 |pages=273–7 |journal=Brain and Nerve }}</ref> and similar species). In addition to killing the prey, part of the function of a haemotoxic venom for some animals is to aid digestion. The venom breaks down protein in the region of the bite, making prey easier to digest.
The process by which a haemotoxin causes death is much slower than that of a [[neurotoxin]]. Snakes which envenomate a prey animal may have to track the prey as it flees. Typically, a [[Mammal|mammalian]] prey will stop fleeing not because of death, but due to shock caused by the venomous bite. Symptoms are dependent upon species, size, location of bite and the amount of venom injected. In humans, symptoms include nausea, disorientation, and headache; these may be delayed for several hours.
Haemotoxins are used in [[medical diagnosis|diagnostic]] studies of the [[coagulation]] system. [[Antiphospholipid syndrome|Lupus anticoagulant]] is detected by changes in the [[dilute Russell's viper venom time]], which is a [[laboratory]] assay based on—as its name indicates—venom of the [[Daboia|Russell's viper]].
==References== {{reflist}}
== External links == {{Wiktionary|hemotoxin}} * [https://web.archive.org/web/20070927203155/http://www.unco.edu/nhs/biology/faculty_staff/mackessy/toxinology.pdf Introduction to the special edition of ''Journal of Toxicology - Toxin Reviews'', 21(1 & 2)]
{{Toxins}}
[[Category:Toxins by organ system affected]] [[Category:Hematology]]