Hematophagy 2177545 223842282 2008-07-06T02:44:58Z Anxietycello 7181612 /* See also */ {{feeding}} {{redirect|Bloodsucker}} [[Image:Anopheles stephensi.jpeg|thumb|250px|right|An ''[[Anopheles|Anopheles stephensi]]'' mosquito obtaining a blood meal from a human host through its pointed proboscis. Note the droplet of blood being expelled from the abdomen after having engorged itself on its host’s blood. This mosquito is a known malarial vector with a distribution that ranges from Egypt all the way to China.]] '''Hematophagy''' (sometimes spelled '''haematophagy''' or '''hematophagia''') is the habit of certain [[animal]]s of [[feeding]] on [[blood]] (from the [[Greek language|Greek]] words, ''haima'' "blood" and ''phagein'' "to eat"). Since blood is a fluid tissue rich in nutritious [[protein]]s and [[lipid]]s that can be taken without enormous effort, hematophagy has evolved as a preferred form of feeding in many small animals such as [[worm]]s and [[arthropod]]s. Some intestinal [[parasitic worm|nematodes]], such as Ancylostomids, feed on blood extracted from the capillaries of the gut and about 75% of all species of [[leech]]es (e.g. ''Hirudo medicinalis''){{Fact|date=June 2007}}, a free-living worm, are hematophagous. Some [[fish]], such as [[lamprey]]s, and [[mammal]]s, especially the [[vampire bat]]s, also practice hematophagy. ==Mechanism and evolution of hematophagy== These hematophagous animals have evolved different specialized [[mouth]] parts and chemical agents for penetrating vascular structures in the [[skin]] of [[host (biology)|hosts]], mostly of mammals, [[bird]]s and [[fish]]. This type of feeding is known as phlebotomy (from the Greek words, ''phleps'' "vein" and ''tomos'' "cutting"). Once phlebotomy is performed (in most insects by a specialized fine hollow "needle" called [[proboscis]] which perforates skin and [[capillary|capillaries]]; in bats by sharp [[incisor|incisor teeth]] that act as a razor to cut the skin), blood is acquired either by sucking action directly from the vases, or from a pool of escaped blood, or by lapping (again, in bats). In order to overcome natural [[hemostasis]] (blood coagulation), [[vasoconstriction]], [[inflammation]] and [[pain]] sensation in the host, biochemical solutions in the [[saliva]] for instance, for pre-injection, [[anesthesia]] and capillary dilation have evolved in different hematophagous species. In fact, new [[anticoagulant]] medicines have been developed on the basis of substances found in the saliva of several hematophagous species, such as leeches ([[hirudin]]). Hematophagy can be classified into '''obligatory''' and '''optional''' practice. Obligatory hematophagous animals do not have any other type of food besides blood; one such species is ''Rhodnius prolixus'' (an [[assassin bug]] from South America). Contrast that with optional hematophages, like the many [[mosquito]]es species, such as ''[[Aedes aegypti]]'', which may also feed on [[pollen]], [[fruit]] juice and other biological fluids besides blood. Sometimes, only the female of the species is a hematophage (this is essential for [[ovum|egg]] production and reproduction). Coyotes, wolves, and other canids may lick blood. Hematophagy has apparently evolved independently in many disparate arthropod, [[annelid]], [[nematode]] and mammalian taxa. For example [[Diptera]] (insects with two [[wing]]s, such as [[fly|flies]]) have eleven families with hematophagous habits (more than half of the 19 hematophagous arthropod taxa). About 14,000 species of arthropods are hematophagous, even including some genera that were not previously thought to be, such as [[moth]]s of the genus ''[[Calyptra (genus)|Calyptra]]''. Several complementary [[biological adaptation]]s for locating the hosts (usually in the dark, as most hematophagous species are [[nocturnal]] and silent, in order to avoid detection and destruction by the host) have also evolved, such as special physical or chemical detectors (for [[sweat]] components, [[carbon dioxide|CO<sub>2</sub>]], [[heat]], [[light]], movement, etc.). ==Medical importance== The phlebotomic action opens a channel for contamination of the host species with [[bacteria]], [[viruses]] and blood-borne [[parasite]]s contained in the hematophagous organism. Thus, many animal and human [[infectious disease]]s are transmitted by hematophagous species, such as the [[bubonic plague]], [[Chagas disease]], [[dengue fever]], [[filariasis]], [[leishmaniasis]], [[Lyme disease]], [[malaria]], [[rabies]], [[sleeping sickness]], [[St. Louis encephalitis]], [[tularemia]], [[typhus]], [[Rocky Mountain spotted fever]], [[West Nile fever]] and many others. Among the hematophagous insects of medical importance are the [[sandfly]], [[blackfly]], [[tsetse fly]], [[bedbug]], [[assassin bug]], [[mosquito]], [[tick]], [[louse]], [[mite]], [[midge (insect)|midge]], [[chigger]]<!-- Though the [[Harvest mite]] is not an insect and it's article says it is not hematophagus, they can cause disease problems. Maybe the [[Chigoe flea]] was meant, which is an insect and could be hematophagus?-->, and [[flea]]. Recently, hematophagous organisms have been used by physicians for beneficial purposes ([[hirudotherapy]]). Some doctors now use leeches to prevent the clotting of blood on some wounds following surgery or trauma.{{Fact|date=June 2008}} The anticoagulants in the laboratory-raised leeches' [[saliva]] keeps fresh blood flowing to the site of an injury, actually preventing infection and increasing chances of full recovery. In a recent study, a genetically engineered drug called [[desmoteplase]] based on the saliva of ''Desmodus rotundus'' (the vampire bat) was shown to improve [[stroke]] patients ==Human hematophagy== Drinking blood and manufacturing foodstuffs and delicacies with animal blood is also a feeding behavior in many societies. For instance, cow blood mixed with [[milk]] is a mainstay food in the African [[Maasai]]. Some sources say that [[Mongols]] would drink blood from one of their horses if it became a necessity. [[Black Pudding]] is eaten in many places around the world. Some societies, such as the [[Moche]], had ritual hematophagy, as well as the [[Scythia]]ns, a nomadic people of [[Russia]], who had the habit of drinking the blood of the first enemy they would kill in [[war|battle]]. Some religious rituals underline the importance of metaphorical hematophagy, such as in the [[transubstantiation]] of wine as the blood of [[Jesus Christ]] during [[Catholic]] [[eucharist]]. Psychiatric cases of patients performing hematophagy also exist. Sucking one's own blood from a wound is also a behaviour commonly seen in humans, and in small enough quantities is not considered taboo. Finally, human [[vampirism]] has been a persistent object of literary and media attention. Judaism, Islam, and Christianity forbid drinking of blood. There are references in the Old and New Testaments clearly prohibiting this practice (see, for instance, Genesis 9:4; Leviticus 3:17, 7:26, 17:12, 17:14, 19:26; Deuteronomy 12:16, 12:23, 15:23; 1 Samuel 14:33-34; Ezekiel 33:25; Acts 15:20, 15:29, 21:25). ==See also== * [[Hirudotherapy]] * [[Natural reservoir]] * [[Tick-borne disease]] * [[Transmission (medicine)]] * [[Zoonosis]] * [[Vampire]] * [[Mosquito]] * [[Reduviidae|Assassin bug]] {{feeding}} ==References== * Scharfetter C, Hagenbuchner K. Blutdurst als Symptom. Ein seltsamer Fall von Bluttrinken. ''Psychiatr Neurol'' (Basel). 1967;154(5):288-310.' * Ciprandi, A; Horn, F; Termignoni, C. Saliva of hematophagous animals: source of new anticoagulants. ''Rev. Bras. Hematol. Hemoter.'', 2003, vol.25, no.4, p.250-262 [http://www.scielo.br/scielo.php?pid=S1516-84842003000400012&script=sci_pdf&tlng=pt PDF full text] * Markwardt F. Hirudin as alternative anticoagulant -- a historical review. ''Semin Thromb Hemost.'' 2002 Oct;28(5):405-14. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12420235&query_hl=2 Medline abstract] * Ribeiro JM. Blood-feeding arthropods: live syringes or invertebrate pharmacologists? ''Infect Agents Dis.'' 1995 Sep;4(3):143-52. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8548192&query_hl=6 Medline abstract] ==External links== {{wiktionarypar|bloodsucker}} * Schutt, W. [http://www.darkbanquet.com A website dedicated to the study of blood feeding creatures] * Galun, R. [http://www.bgu.ac.il/desert_ecology/ecology/Ziv%202003.htm#Galun Evolution of Hematophagy] * Beaty, LC. [http://www.colostate.edu/Depts/Entomology/courses/en507/papers_1997/beaty.html Host-Seeking Behavior in Hematophagous Mosquitoes] * [http://www.leechesturkey.com Supplier of Medicinal Leeches] [[Category:Eating behaviors]] [[Category:Ecology]] [[de:Hämatophagie]] [[es:Hematofagia]] [[fr:Hématophage]] [[is:Blóðæta]] [[it:Ematofagia]] [[ja:吸血動物]] [[pl:Hematofag]] [[simple:Hematophagy]]