Wikipedia

Human parasite

Not to be confused withParasitism (social offense).

Human parasitesinclude variousprotozoaandworms.

Human parasites are divided into endoparasites, which cause infection inside the body, and ectoparasites, which cause infection superficially within the skin.

The cysts and eggs of endoparasites may be found infeces,which aids in the detection of the parasite in the human host while also providing the means for the parasitic species to exit the current host and enter other hosts.[1]Although there are a number of ways in which humans can contract parasitic infections, observing basic hygiene and cleanliness tips can reduce its probability.[2] The most accurate diagnosis is by qPcr DNA antigen assay[citation needed],not generally available by primary care physicians in the USA: most labs offer research only service.

History

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Archaeological evidence

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It was assumed that early human ancestors generally had parasites, but until recently there was no evidence to support this claim. Generally, the discovery of parasites in ancient humans relies on the study of feces and otherfossilizedmaterial. The earliest known parasite in a human was eggs of thelung flukefound in fossilized feces in northernChileand is estimated to be from around 5900 BC. There are also claims ofhookwormeggs from around 5000 BC inBraziland largeroundwormeggs from around 2330 BC in Peru.Tapewormeggs have also been found present inEgyptianmummiesdating from around 2000 BC, 1250 BC, and 1000 BC along with a well preserved and calcified female worm inside of a mummy.[3]: 171–173 

Written evidence

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The first written records of parasites date from 3000 to 400 BC in Egyptianpapyrusrecords. They identify parasites such as roundworms,Guinea worms,threadworms,and some tapeworms of unknown varieties. In ancientGreece,HippocratesandAristotledocumented several parasites in his collection of works Corpus Hippocraticus. In this book, they documented the presence of worms and other parasites inside of fish, domesticated animals, and humans. Thebladder wormis well documented in its presence in pigs along with the larval stages of a tapeworm (Taenia solium). These tapeworms were mentioned in a play byAristophanesas "hailstones" with Aristotle in the section about pig diseases in his bookHistory of Animals.The cysts of theEchinococcus granulosustapeworm were also well known in ancient cultures mainly because of their presence in slaughtered and sacrificed animals.[3]: 173–174  The major parasitic disease that has been documented in early records isdracunculiasis.This disease is caused by the Guinea worm and is characterized by the female worm emerging from the leg. This symptom is so specific to the disease that it is mentioned in many texts and plays that predate 1000 AD.[3]: 173 

Greece and Rome

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In Greece, Hippocrates and Aristotle created considerable medical documentation about parasites in the Corpus Hippocraticus. In this work, they documented the presence of parasitic worms in many animals ranging from fish to domesticated animals and humans. Among the most extensively documented was the Bladder Worm (Taenia solium). This condition was called "measly pork" when present in pigs and was characterized by the presence of thelarvalstages of the Bladder Worm in muscle tissue. This disease was also mentioned by the playwright Aristophanes when he referred to "hailstones" in one of his plays. This naming convention is also reflected by Aristotle when he refers to "bladders that are like hailstones."[3]: 173  Another worm that was commonly written about in ancient Greek texts was the tapewormEchinococccus granulosus.This worm was distinguished by the presence of "massive cysts" in theliverof animals. This condition was documented so well mainly because of its presence in slaughtered andsacrificed animals.It was documented by several different cultures of the time other than the Greeks including theArabs,Romans,andBabylonians.[3]: 173–174  Not many parasitic diseases were identified in ancient Greek and Roman texts mainly because the symptoms for parasitic diseases are shared with many other illnesses such as theflu,thecommon cold,anddysentery.However, several diseases such asDracunculiasis(Guinea worm disease), Hookworm,Elephantiasis,Schistosomiasis,Malaria,andAmebiasiscause unique and specific symptoms and are well documented because of this. The most documented by far was Guinea worm disease mainly because the grown female worm emerges from the skin, which causes considerable irritation, and which cannot really be ignored. This particular disease is widely accepted to also be the "fiery serpents" written about in the Old Testament of theBible.[4]This disease was mentioned by Hippocrates in Greece along withPliny the Elder,Galen,Aetius of Amida,andPaulus Aeginetaof Alexandria in Rome. Strangely, this disease was never present in Greece even though it was documented.[3]: 174 

Northern Africa, the Middle East, and Mesopotamia

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The medieval Persian doctorAvicennarecords the presence of severalparasitesinanimalsand in hispatientsincludingGuinea worm,threadworms,tapeworms,and theAscaris worm.This followed a tradition ofArabmedical writings spanning over 1000 years in the area near theRed Sea.However, theArabsnever made the connection betweenparasitesand thediseasesthey caused.[3]: 174  As withGreekandRomantexts, theGuinea wormis very well documented inMiddle Easternmedical texts. SeveralAssyriandocumentsin thelibraryof KingAshurbanipalrefer to an affliction that has been interpreted asGuinea worm disease.[3]: 174  InEgypt,theEbers Papyruscontains one of the few references tohookwormdiseasein ancient texts. This disease does not have very specificsymptomsand was vaguely mentioned. However vague the reference, it is one of the few that connect the disease to the hookwormparasite.[3]: 174 Another documented disease is elephantiasis. Symptoms of this disease are highly visible, since it causes extreme swelling in the limbs, breasts, andgenitals.A number of survivingstatuesindicate thatPharaohMentuhotep IIis likely to have suffered from elephantiasis. This disease was well known toArabphysiciansandAvicenna,who noted specific differences between elephantiasis andleprosy.[3]: 175 

China

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TheChinesemostly documented diseases rather than the parasites associated with them. Chinese texts contain one of the few references to hookworm disease found in ancient records, but no connection to the hookworm parasite is made.[3]: 174 The Emperor Huang Ti recorded the earliest mentioning (2700 BC) of malaria in his text Nei Ching. He lists chills, headaches, and fevers as the main symptoms and distinguished between the different kinds of fevers.

India

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InIndia,theCharaka SamhitaandSushruta Samhitadocument malaria. These documents list the main symptoms as fever and enlarged spleens.[3][failed verification]TheBhrigu Samhitafrom 1000 BCE makes the earliest reference to Amebiasis. The symptoms were given as bloody and mucosal diarrhea.[3]

Most common parasites

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As of 2013, the parasites causing the most deaths globally were as follows:[5]

Parasitic Disease Global Deaths in 2013
Malaria 854,600
Leishmaniasis(Kala-azar) 62,500
Cryptosporidiosis 41,900
Amoebiasis 11,300
Chagas disease 10,600
African trypanosomiasis 6,900
Schistosomiasis 5,500
Ascariasis 4,500
Cystic echinococcosis 2,200
Cysticercosis 700
Total Deaths from Parasitic Infections 1,000,700

Commonly documented parasites

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Further information:List of parasites of humans

Endoparasites

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Protozoa

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Parasitic worms (helminths)

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Guinea worm(Dracunculus) wrapped around a match stick

Parasitic flukes

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Other organisms

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Ectoparasites

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References

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  1. ^"Krumhardt, Barbera, PhD. Human Parasites. 8 October 2008".Archived fromthe originalon 16 December 2008.Retrieved17 December2008.
  2. ^"Parasites – How they enter our body and ten precautions to avoid an infection".
  3. ^abcdefghijklmCox, Francis E. G. "History of human parasitic diseases."Infectious Disease Clinics of North AmericaJune 2004
  4. ^Kuchenmeister, F.Animal and vegetableparasites.London: The Sydenham Society,1857
  5. ^"One Million Deaths by Parasites | Speaking of Medicine".16 January 2015.Retrieved18 September2016.
  6. ^Greenaway, C. "Dracunculiasis".Canadian Medical Association Journal(Feb 2004)
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