Haemotoxins, hemotoxins or hematotoxins are

toxin A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived ...

s that destroy

red blood cell Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...

s, disrupt

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

clotting, and/or cause

organ Organ and organs may refer to: Biology * Organ (biology), a group of tissues organized to serve a common function * Organ system, a collection of organs that function together to carry out specific functions within the body. Musical instruments ...

degeneration and generalized tissue damage. The term ''haemotoxin'' is to some degree a

misnomer A misnomer is a name that is incorrectly or unsuitably applied. Misnomers often arise because something was named long before its correct nature was known, or because an earlier form of something has been replaced by a later form to which the nam ...

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

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 ...

animals, including snakes (

viper Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous and have long (relative to non-vipe ...

s and

pit viper The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . or pit adders, are a subfamily (biology), subfamily of Viperidae, vipers found in Asia and the ...

s) and spiders ( brown recluse). Animal venoms contain

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s and other

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

s that are haemotoxic or

neurotoxic Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifical ...

or occasionally both (as in the Mojave rattlesnake, the Japanese mamushi, 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 Neurotoxins are toxins that are destructive to nervous tissue, nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insult (medical), insultsSpencer 2000 that can adversely affect function ...

. Snakes which envenomate a prey animal may have to track the prey as it flees. Typically, a

mammalian A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

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

diagnostic Diagnosis (: diagnoses) is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in a lot of different academic discipline, disciplines, with variations in the use of logic, analytics, and experience, to determine " ...

studies of the

coagulation Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a thrombus, blood clot. It results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The process of co ...

system.

Lupus anticoagulant Lupus anticoagulant is an immunoglobulin that binds to phospholipids and proteins associated with the cell membrane. Its name is a partial misnomer, as it is actually a prothrombotic antibody ''in vivo''. The name derives from their properties ''i ...

is detected by changes in the dilute Russell's viper venom time, which is a

laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as schools ...

assay based on—as its name indicates—venom of the

Russell's viper Russell's viper (''Daboia russelii)'' is a species of highly venomous snake in the Family (biology), family Viperidae. The species is native to South Asia. It was Species description, described in 1797 by George Shaw (biologist), George Shaw and ...

References

External links

Introduction to the special edition of ''Journal of Toxicology - Toxin Reviews'', 21(1 & 2)
{{Toxins Toxins by organ system affected Hematology