Hematophagy(sometimes spelledhaematophagyorhematophagia) is the practice by certainanimalsoffeedingonblood(from theGreekwords αἷμαhaima"blood" and φαγεῖνphagein"to eat" ). Since blood is a fluid tissue rich in nutritiousproteinsandlipidsthat can be taken without great effort, hematophagy is a preferred form of feeding for many small animals, such aswormsandarthropods.Some intestinalnematodes,such asAncylostomatids,feed on blood extracted from the capillaries of the gut, and about 75 percent of all species ofleeches(e.g.,Hirudo medicinalis) are hematophagous. The spiderEvarcha culicivorafeeds indirectly on vertebrate blood by specializing on blood-filled female mosquitoes as their preferred prey.[1]Somefish,such aslampreysandcandirus;mammals,especiallyvampire bats;and birds, including thevampire finch,Hood mockingbird,Tristan thrush,andoxpeckers,also practise hematophagy.
Mechanism and evolution
editHematophagous animals havemouthparts and chemical agents for penetrating vascular structures in the skin ofhosts,mostly of mammals, birds, and fish. This type of feeding is known as phlebotomy (from the Greek words,phleps"vein" andtomos"cutting" ).
Once phlebotomy is performed (in most insects by a specialized fine hollow "needle", theproboscis,which perforates skin andcapillaries;in bats by sharpincisor teeththat act as a razor to cut the skin), blood is acquired either by sucking action directly from the veins or capillaries, from a pool of escaped blood, or by lapping (again, in bats). To overcome naturalhemostasis(blood coagulation),vasoconstriction,inflammation, and pain sensation in the host, hematophagous animals haveevolvedchemical solutions, in their saliva for instance, that they pre-inject—andanesthesiaand capillary dilation have evolved in some hematophagous species. Scientists have developedanticoagulantmedicines from studying substances in the saliva of several hematophagous species, such as leeches (hirudin).
Hematophagy is classified as eitherobligatoryorfacultative.Obligatory hematophagous animals cannot survive on any other food. Examples includeRhodnius prolixus,a South Americanassassin bug,andCimex lectularius,the human bed bug. Facultative hematophages, meanwhile, acquire at least some portion of their nutrition from non-blood sources in at least one of the sexually mature forms. Examples of this include many mosquito species, such asAedes aegypti,whose both males and females feed on pollen and fruit juice for survival, but the females require a blood meal to produce their eggs. Fly species such asLeptoconops torrenscan also be facultative hematophages. Inanautogenousspecies, the female can survive without blood but must consume blood in order to produce eggs (obligatory hematophages are by definition also anautogenous).
As a feeding practice, hematophagy has evolved independently in a number of arthropod,annelid,nematodeand mammalian taxa. For example,Diptera(insects with two wings, such asflies) 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 moths of the genusCalyptra.Hematophagy in insects, including mosquitoes, is thought to have arisen from phytophagous or entomophagous origins.[2][3][4][5]Several complementarybiological adaptationsfor locating the hosts (usually in the dark, as most hematophagous species are nocturnal and silent to avoid detection) have also evolved, such as special physical or chemical detectors forsweat components,CO2,heat, light, movement, etc.
In addition to these biological adaptations that have evolved to help blood-feeding arthropods locate hosts, there is evidence that RNA from host species may also be taken up and have regulatory consequences in blood feeding insects. A study on the yellow fever mosquitoAedes aegyptihas shown that human blood microRNA has-miR-21 are taken up during blood feeding and transported into the fat body tissues. Once in the fat body they target and regulate mosquito genes such asvitellogenin,which is a yolk protein used for egg production.[6]
Medical importance
editThe phlebotomic action opens a channel for contamination of the host species withbacteria,virusesand blood-borneparasitescontained in the hematophagous organism. Thus, many animal and humaninfectious diseasesare transmitted by hematophagous species, such as thebubonic plague,Chagas disease,dengue fever,eastern equine encephalitis,filariasis,leishmaniasis,Lyme disease,malaria,rabies,sleeping sickness,St. Louis encephalitis,tularemia,typhus,Rocky Mountain spotted fever,West Nile fever,Zika fever,and many others.
Insects andarachnidsof medical importance for being hematophagous, at least in some species, include thesandfly,blackfly,tsetse fly,bedbug,assassin bug,mosquito,tick,louse,mite,midge,andflea.
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.[citation needed]The anticoagulants in the laboratory-raised leeches'salivakeeps 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 calleddesmoteplasebased on the saliva ofDesmodus rotundus(a vampire bat) was shown to improve recovery instrokepatients.[7]
Human hematophagy
editMany human societies also drink blood or use it to manufacture foodstuffs and delicacies. Cow blood mixed withmilk,for example, is a mainstay food of the AfricanMaasai.Many places around the world eatblood sausage.Some societies, such as theMoche,had ritual hematophagy, as well as theScythians,a nomadic people ofEastern Europe,who drank the blood of the first enemy they killed inbattle.Psychiatric cases of patients performing hematophagy also exist. Sucking or licking one's own blood from a wound to clean it is also a common human behavior[dubious–discuss],and in small enough quantities is not considered taboo. Finally, humanvampirismhas been a persistent object of literary and cultural attention.[citation needed]
See also
editReferences
edit- ^Jackson, R. R.; Nelson, X. J. (2012)."Evarcha culicivora chooses blood-fed Anopheles mosquitoes but other East African jumping spiders do not".Medical and Veterinary Entomology.26(2): 233–235.doi:10.1111/j.1365-2915.2011.00986.x.hdl:10092/9753.PMID22032682.S2CID25520447.
- ^Lehane MJ (2005).The biology of blood-sucking in insects(2nd ed.). Cambridge: Cambridge University Press.ISBN0511115539.OCLC61354292.
- ^Mattingly PF (1965). Taylor AE (ed.)."The evolution of parasite-arthropod vector systems".Evolution of Parasites. Symposium of the British Society for Parasitology (3rd), London, November 6, 1964.Oxford: Blackwell Scientific Publications.: 29–45.
- ^Peach DA, Gries R, Zhai H, Young N, Gries G (March 2019)."Multimodal floral cues guide mosquitoes to tansy inflorescences".Scientific Reports.9(1): 3908.Bibcode:2019NatSR...9.3908P.doi:10.1038/s41598-019-39748-4.PMC6405845.PMID30846726.
- ^Peach DA, Gries G (2019)."Mosquito phytophagy – sources exploited, ecological function, and evolutionary transition to haematophagy".Entomologia Experimentalis et Applicata.168(2): 120–136.doi:10.1111/eea.12852.ISSN1570-7458.
- ^Perdomo, Hugo D.; Hussain, Mazhar; Parry, Rhys; Etebari, Kayvan; Hedges, Lauren M.; Zhang, Guangmei; et al. (2021)."Human blood microRNA hsa-miR-21-5p induces vitellogenin in the mosquito Aedes aegypti".Commun Biol.4(1): 856.doi:10.1038/s42003-021-02385-7.PMC8270986.PMID34244602.
- ^Furlan, Anthony J.; Eyding, Dirk; Albers, Gregory W.; Al-Rawi, Yasir; Lees, Kennedy R.; Rowley, Howard A.; Sachara, Christian; Soehngen, Mariola; Warach, Steven; Hacke, Werner; DEDAS Investigators (2006)."Dose Escalation of Desmoteplase for Acute Ischemic Stroke (DEDAS)".Stroke.37(5): 1227–1231.doi:10.1161/01.STR.0000217403.66996.6d.PMID16574922.S2CID2547258.
Further reading
edit- Scharfetter C, Hagenbuchner K (1967). "Blutdurst als Symptom. Ein seltsamer Fall von Bluttrinken".Psychiatr Neurol.154(5). Basel: 288–310.doi:10.1159/000126021.
- Ciprandi A, Horn F, Termignoni C (2003)."Saliva of hematophagous animals: source of new anticoagulants"(PDF).Rev. Bras. Hematol. Hemoter.25(4): 250–262.
- Markwardt F (October 2002). "Hirudin as alternative anticoagulant--a historical review".Seminars in Thrombosis and Hemostasis.28(5): 405–14.doi:10.1055/s-2002-35292.PMID12420235.S2CID23103375.
- Ribeiro JM (September 1995). "Blood-feeding arthropods: live syringes or invertebrate pharmacologists?".Infectious Agents and Disease.4(3): 143–52.PMID8548192.
