Human parasites include various

protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

and

worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wor ...

s. 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 in

feces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a rela ...

, 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. Although there are a number of ways in which humans can contract parasitic infections, observing basic hygiene and cleanliness tips can reduce its probability. The most accurate diagnosis is by qPcr DNA antigen assay, not generally available by primary care physicians in the USA: most labs offer research only service.

History

Archaeological evidence

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 other fossilized material. The earliest known parasite in a human was eggs of the lung fluke found in fossilized feces in northern

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

and is estimated to be from around 5900 BC. There are also claims of

hookworm Hookworms are intestinal, blood-feeding, parasitic roundworms that cause types of infection known as helminthiases. Hookworm infection is found in many parts of the world, and is common in areas with poor access to adequate water, sanitation, ...

eggs from around 5000 BC in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

and large roundworm eggs from around 2330 BC in Peru.

Tapeworm Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cesto ...

eggs have also been found present in Egyptian

mummies A mummy is a dead human or an animal whose soft tissues and organs have been preserved by either intentional or accidental exposure to chemicals, extreme cold, very low humidity, or lack of air, so that the recovered body does not decay furt ...

dating from around 2000 BC, 1250 BC, and 1000 BC along with a well preserved and calcified female worm inside of a mummy.Cox, Francis E. G. "History of human parasitic diseases." ''Infectious Disease Clinics of North America'' June 2004

Written evidence

The first written records of parasites date from 3000 to 400 BC in Egyptian

papyrus Papyrus ( ) is a material similar to thick paper that was used in ancient times as a writing surface. It was made from the pith of the papyrus plant, '' Cyperus papyrus'', a wetland sedge. ''Papyrus'' (plural: ''papyri'') can also refer to ...

records. They identify parasites such as roundworms,

Guinea worm ''Dracunculus medinensis'', or Guinea worm, is a nematode that causes dracunculiasis, also known as guinea worm disease. The disease is caused by the female which, at up to in length, is among the longest nematodes infecting humans. In contr ...

s, threadworms, and some tapeworms of unknown varieties. In ancient

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders wi ...

Hippocrates Hippocrates of Kos (; grc-gre, Ἱπποκράτης ὁ Κῷος, Hippokrátēs ho Kôios; ), also known as Hippocrates II, was a Greek physician of the classical period who is considered one of the most outstanding figures in the history o ...

and

Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of ...

documented 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. The bladder worm is well documented in its presence in pigs along with the larval stages of a tapeworm ('' Taenia solium''). These tapeworms were mentioned in a play by

Aristophanes Aristophanes (; grc, Ἀριστοφάνης, ; c. 446 – c. 386 BC), son of Philippus, of the deme Kydathenaion ( la, Cydathenaeum), was a comic playwright or comedy-writer of ancient Athens and a poet of Old Attic Comedy. Eleven of his ...

as "hailstones" with Aristotle in the section about pig diseases in his book ''

History of Animals ''History of Animals'' ( grc-gre, Τῶν περὶ τὰ ζῷα ἱστοριῶν, ''Ton peri ta zoia historion'', "Inquiries on Animals"; la, Historia Animalium, "History of Animals") is one of the major Aristotle's biology, texts on biolo ...

''. The cysts of the ''

Echinococcus granulosus ''Echinococcus granulosus,'' also called the hydatid worm, hyper tape-worm or dog tapeworm, is a cyclophyllid cestode that dwells in the small intestine of canids as an adult, but which has important intermediate hosts such as livestock and hu ...

'' tapeworm were also well known in ancient cultures mainly because of their presence in slaughtered and sacrificed animals. The major parasitic disease that has been documented in early records is

dracunculiasis Dracunculiasis, also called Guinea-worm disease, is a parasitic infection by the Guinea worm, ''Dracunculus medinensis''. A person becomes infected by drinking water containing water fleas infected with guinea worm larvae. The worms penetrate t ...

. 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.

Greece and Rome

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 the

larval A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

stages 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." Another worm that was commonly written about in ancient Greek texts was the tapeworm ''Echinococccus granulosus''. This worm was distinguished by the presence of "massive cysts" in the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it i ...

of animals. This condition was documented so well mainly because of its presence in slaughtered and sacrificed animals. It was documented by several different cultures of the time other than the Greeks including the

Arabs The Arabs (singular: Arab; singular ar, عَرَبِيٌّ, DIN 31635: , , plural ar, عَرَب, DIN 31635: , Arabic pronunciation: ), also known as the Arab people, are an ethnic group mainly inhabiting the Arab world in Western Asia, ...

Romans Roman or Romans most often refers to: *Rome, the capital city of Italy * Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a lette ...

, and

Babylonians Babylonia (; Akkadian: , ''māt Akkadī'') was an ancient Akkadian-speaking state and cultural area based in the city of Babylon in central-southern Mesopotamia (present-day Iraq and parts of Syria). It emerged as an Amorite-ruled state c. 1 ...

. 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 the flu, the

common cold The common cold or the cold is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear fewer than two days after expos ...

, and

dysentery Dysentery (UK pronunciation: , US: ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications ...

. However, several diseases such as

Dracunculiasis Dracunculiasis, also called Guinea-worm disease, is a parasitic infection by the Guinea worm, ''Dracunculus medinensis''. A person becomes infected by drinking water containing water fleas infected with guinea worm larvae. The worms penetrate t ...

(Guinea worm disease), Hookworm,

Elephantiasis Elephantiasis is the enlargement and hardening of limbs or body parts due to tissue swelling. It is characterised by edema, hypertrophy, and fibrosis of skin and subcutaneous tissues, due to obstruction of lymphatic vessels. It may affect the genit ...

Schistosomiasis Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, blo ...

Malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. ...

, and

Amebiasis Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba ''Entamoeba histolytica''. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic u ...

cause 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 the

Bible The Bible (from Koine Greek , , 'the books') is a collection of religious texts or scriptures that are held to be sacred in Christianity Christianity is an Abrahamic monotheistic religion based on the life and teachings of Jesus ...

. This disease was mentioned by Hippocrates in Greece along with

Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic ' ...

Galen Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be o ...

Aetius of Amida Aetius, Aëtius, or Aetios (Ἀέτιος) may refer to: People * Aetius (philosopher), 1st- or 2nd-century doxographer and Eclectic philosopher * Aëtius of Antioch, 4th-century Anomean theologian * Flavius Aetius, Western Roman commander in ch ...

, and

Paulus Aegineta Paul of Aegina or Paulus Aegineta ( el, Παῦλος Αἰγινήτης; Aegina, ) was a 7th-century Byzantine Greek physician best known for writing the medical encyclopedia ''Medical Compendium in Seven Books.'' He is considered the “Fathe ...

of Alexandria in Rome. Strangely, this disease was never present in Greece even though it was documented.

Northern Africa, the Middle East, and Mesopotamia

The medieval Persian doctor

Avicenna Ibn Sina ( fa, ابن سینا; 980 – June 1037 CE), commonly known in the West as Avicenna (), was a Persian polymath who is regarded as one of the most significant physicians, astronomers, philosophers, and writers of the Islamic ...

records the presence of several

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage ...

s and in his

patient A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other heal ...

s including

, threadworms,

tapeworms Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of ...

, and the Ascaris worm. This followed a tradition of

Arab The Arabs (singular: Arab; singular ar, عَرَبِيٌّ, DIN 31635: , , plural ar, عَرَب, DIN 31635: , Arabic pronunciation: ), also known as the Arab people, are an ethnic group mainly inhabiting the Arab world in Western Asia, ...

medical writings spanning over 1000 years in the area near the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...

. However, the

never made the connection between

and the

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

s they caused. As with

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

and

Roman Roman or Romans most often refers to: * Rome, the capital city of Italy * Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a lett ...

texts, the

is very well documented in

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...

ern medical texts. Several

Assyria Assyria ( Neo-Assyrian cuneiform: , romanized: ''māt Aššur''; syc, ܐܬܘܪ, ʾāthor) was a major ancient Mesopotamian civilization which existed as a city-state at times controlling regional territories in the indigenous lands of the A ...

document A document is a written, drawn, presented, or memorialized representation of thought, often the manifestation of non-fictional, as well as fictional, content. The word originates from the Latin ''Documentum'', which denotes a "teaching" o ...

s in the

library A library is a collection of materials, books or media that are accessible for use and not just for display purposes. A library provides physical (hard copies) or digital access (soft copies) materials, and may be a physical location or a vi ...

of King

Ashurbanipal Ashurbanipal ( Neo-Assyrian cuneiform: , meaning " Ashur is the creator of the heir") was the king of the Neo-Assyrian Empire from 669 BCE to his death in 631. He is generally remembered as the last great king of Assyria. Inheriting the throne a ...

refer to an affliction that has been interpreted as

Guinea worm disease Dracunculiasis, also called Guinea-worm disease, is a parasitic infection by the Guinea worm, ''Dracunculus medinensis''. A person becomes infected by drinking water containing water fleas infected with guinea worm larvae. The worms penetrate t ...

. In

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a List of transcontinental countries, transcontinental country spanning the North Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via a land bridg ...

, the Ebers Papyrus contains one of the few references to

in ancient texts. This disease does not have very specific

symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...

s and was vaguely mentioned. However vague the reference, it is one of the few that connect the disease to the hookworm

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...

. Another documented disease is elephantiasis. Symptoms of this disease are highly visible, since it causes extreme swelling in the limbs, breasts, and

genitals A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...

. A number of surviving

statue A statue is a free-standing sculpture in which the realistic, full-length figures of persons or animals are carved or cast in a durable material such as wood, metal or stone. Typical statues are life-sized or close to life-size; a sculpture t ...

s indicate that

Pharaoh Pharaoh (, ; Egyptian: '' pr ꜥꜣ''; cop, , Pǝrro; Biblical Hebrew: ''Parʿō'') is the vernacular term often used by modern authors for the kings of ancient Egypt who ruled as monarchs from the First Dynasty (c. 3150 BC) until th ...

Mentuhotep II Mentuhotep II ( egy, Mn- ṯw- ḥtp, meaning " Mentu is satisfied"), also known under his prenomen Nebhepetre ( egy, Nb- ḥpt- Rˁ, meaning "The Lord of the rudder is Ra"), was an ancient Egyptian pharaoh, the sixth ruler of the Eleventh ...

is likely to have suffered from elephantiasis. This disease was well known to

physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...

s and

, who noted specific differences between elephantiasis and

leprosy Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria '' Mycobacterium leprae'' or '' Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve d ...

China

The Chinese mostly 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. 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

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

, the

Charaka Samhita The ''Charaka Samhita'' (, “Compendium of '' Charaka''”) is a Sanskrit text on Ayurveda (Indian traditional medicine). Along with the '' Sushruta Samhita'', it is one of the two foundational texts of this field that have survived from anci ...

and

Sushruta Samhita The ''Sushruta Samhita'' (सुश्रुतसंहिता, IAST: ''Suśrutasaṃhitā'', literally "Suśruta's Compendium") is an ancient Sanskrit text on medicine and surgery, and one of the most important such treatises on this subje ...

document malaria. These documents list the main symptoms as fever and enlarged spleens. The

Bhrigu Samhita The ''Bhrigu Saṃhitā'' is a Sanskrit astrological (Jyotisha) treatise attributed in its introduction to Bhrigu, one of the " Saptarishis" ("seven sages") of the Vedic period. Its introductory chapter states that it was compiled by the sapt ...

from 1000 BCE makes the earliest reference to Amebiasis. The symptoms were given as bloody and mucosal diarrhea.

Most common parasites

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

Commonly documented parasites

Endoparasites

Protozoa

* ''

Plasmodium ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a blood-feeding insect host which then injects parasites into a ve ...

'' spp.: causes

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. ...

* ''

Entamoeba ''Entamoeba'' is a genus of Amoebozoa found as internal parasites or commensals of animals. In 1875, Fedor Lösch described the first proven case of amoebic dysentery in St. Petersburg, Russia. He referred to the amoeba he observed microsco ...

'': causes

amoebiasis Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba '' Entamoeba histolytica''. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ...

* ''

Giardia ''Giardia'' ( or ) is a genus of anaerobic flagellated protozoan parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and ...

'': causes giardiasis * ''

Trypanosoma brucei ''Trypanosoma brucei'' is a species of parasitic kinetoplastid belonging to the genus '' Trypanosoma'' that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is exclusively extrace ...

'': causes

African trypanosomiasis African trypanosomiasis, also known as African sleeping sickness or simply sleeping sickness, is an insect-borne parasitic infection of humans and other animals. It is caused by the species '' Trypanosoma brucei''. Humans are infected by two t ...

* '' Toxoplasma gondii'': causes

toxoplasmosis Toxoplasmosis is a parasitic disease caused by '' Toxoplasma gondii'', an apicomplexan. Infections with toxoplasmosis are associated with a variety of neuropsychiatric and behavioral conditions. Occasionally, people may have a few weeks or mont ...

* ''

Acanthamoeba ''Acanthamoeba'' is a genus of amoebae that are commonly recovered from soil, fresh water, and other habitats. ''Acanthamoeba'' has two evolutive forms, the metabolically active trophozoite and a dormant, stress-resistant cyst. Trophozoites are ...

'': causes

acanthamoeba keratitis ''Acanthamoeba'' keratitis (AK) is a rare disease in which amoebae of the genus ''Acanthamoeba'' invade the clear portion of the front (cornea) of the eye. It affects roughly 100 people in the United States each year. ''Acanthamoeba'' are proto ...

* ''

Leishmania ''Leishmania'' is a parasitic protozoan, a single-celled organism of the genus '' Leishmania'' that are responsible for the disease leishmaniasis. They are spread by sandflies of the genus ''Phlebotomus'' in the Old World, and of the genus ' ...

'': causes

leishmaniasis Leishmaniasis is a wide array of clinical manifestations caused by parasites of the trypanosome genus '' Leishmania''. It is generally spread through the bite of phlebotomine sandflies, ''Phlebotomus'' and ''Lutzomyia'', and occurs most freq ...

* ''

Babesia ''Babesia'', also called ''Nuttallia'', is an apicomplexan parasite that infects red blood cells and is transmitted by ticks. Originally discovered by the Romanian bacteriologist Victor Babeș in 1888, over 100 species of ''Babesia'' have since ...

'': causes

babesiosis Babesiosis or piroplasmosis is a malaria-like parasitic disease caused by infection with a eukaryotic parasite in the order Piroplasmida, typically a ''Babesia'' or ''Theileria'', in the phylum Apicomplexa. Human babesiosis transmission via tic ...

* ''

Balamuthia mandrillaris ''Balamuthia mandrillaris'' is a free-living amoeba that causes the rare but deadly neurological condition granulomatous amoebic encephalitis (GAE). ''B. mandrillaris'' is a soil-dwelling amoeba and was first discovered in 1986 in the brain of a ...

'': causes granulomatous amoebic encephalitis * ''

Cryptosporidium ''Cryptosporidium'', sometimes informally called crypto, is a genus of apicomplexan parasitic alveolates that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea (intestinal crypt ...

'': causes

cryptosporidiosis Cryptosporidiosis, sometimes informally called crypto, is a parasitic disease caused by '' Cryptosporidium'', a genus of protozoan parasites in the phylum Apicomplexa. It affects the distal small intestine and can affect the respiratory tra ...

* ''

Cyclospora ''Cyclospora'' is a genus of apicomplexan parasites. It includes the species ''Cyclospora cayetanensis'', the causative agent of cyclosporiasis. Members of ''Cyclospora'' are characterized as having oocysts with two sporocysts, each containing ...

'': causes cyclosporiasis * ''

Naegleria fowleri ''Naegleria fowleri'', colloquially known as a "brain-eating amoeba", is a species of the genus ''Naegleria'', belonging to the phylum Percolozoa, which is technically not classified as true amoeba, but a shapeshifting amoeboflagellate excava ...

'': causes primary amoebic meningoencephalitis

Parasitic worms (helminths)

* ''

Ascaris lumbricoides ''Ascaris lumbricoides'' is a large parasitic worm that causes ascariasis in humans. A roundworm of genus ''Ascaris'', it is the most common parasitic worm in humans. An estimated one-sixth of the human population is at some point infected by ...

'': causes

ascariasis Ascariasis is a disease caused by the parasitic roundworm ''Ascaris lumbricoides''. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present and may i ...

* Pinworm: causes enterobiasis * '' Strongyloides stercoralis'': causes trongyloidiasis * '' Toxocara'': causes

toxocariasis Toxocariasis is an illness of humans caused by the dog roundworm (''Toxocara canis'') and, less frequently, the cat roundworm ('' Toxocara cati'').https://academic.oup.com/ajcp/article/142/suppl_1/A104/1771175 Eosinophilic Pseudoleukemia Due to T ...

: causes

.Greenaway, C. "Dracunculiasis". ''Canadian Medical Association Journal'' (Feb 2004) *

Hookworm Hookworms are intestinal, blood-feeding, parasitic roundworms that cause types of infection known as helminthiases. Hookworm infection is found in many parts of the world, and is common in areas with poor access to adequate water, sanitation, ...

: causes

helminthiasis Helminthiasis, also known as worm infection, is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms, known as helminths. There are numerous species of these parasites, which are ...

(''Eucestoda''): causes

cysticercosis Cysticercosis is a tissue infection caused by the young form of the pork tapeworm. People may have few or no symptoms for years. In some cases, particularly in Asia, solid lumps of between one and two centimetres may develop under the skin. Aft ...

echinococcosis Echinococcosis is a parasitic disease of tapeworms of the ''Echinococcus'' type. The two main types of the disease are ''cystic echinococcosis'' and '' alveolar echinococcosis''. Less common forms include ''polycystic echinococcosis'' and ''u ...

, hymenolepiasis,

diphyllobothriasis Diphyllobothriasis is the infection caused by tapeworms of the genus ''Diphyllobothrium'' (commonly '' D. latum'' and ''D. nihonkaiense''). Diphyllobothriasis mostly occurs in regions where raw fish is regularly consumed; those who consume raw fi ...

and

sparganosis Sparganosis is a parasitic infection caused by the plerocercoid larvae of the genus '' Spirometra'' including ''S. mansoni'', ''S. ranarum'', ''S. mansonoides'' and ''S. erinacei''.John, D.T. and Petri, W.A. Markell and Voge's Medical Parasitol ...

* Whipworm (''Trichuris trichiura''): causes

trichuriasis Trichuriasis, also known as whipworm infection, is an infection by the parasitic worm '' Trichuris trichiura'' (whipworm). If infection is only with a few worms, there are often no symptoms. In those who are infected with many worms, there may ...

Parasitic flukes

* ''

Schistosoma ''Schistosoma'' is a genus of trematodes, commonly known as blood flukes. They are parasitic flatworms responsible for a highly significant group of infections in humans termed '' schistosomiasis'', which is considered by the World Health Org ...

'': causes

schistosomiasis Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, blo ...

* ''

Gnathostoma ''Gnathostoma'' is a genus of parasitic nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelw ...

'': causes gnathostomiasis * '' Paragonimus'': causes paragonimiasis * '' Fasciola hepatica'': causes

fascioliasis Fasciolosis is a parasitic worm infection caused by the common liver fluke '' Fasciola hepatica'' as well as by '' Fasciola gigantica''. The disease is a plant-borne trematode zoonosis, and is classified as a neglected tropical disease (NTD). ...

* ''

Trichobilharzia regenti ''Trichobilharzia regenti'' is a neuropathogenic parasitic flatworm of birds which also causes cercarial dermatitis in humans. The species was originally described in 1998 in the Czech Republic and afterwards it was detected also in other Europe ...

'': causes

cercarial dermatitis Swimmer's itch, cercarial dermatitis or schistosome dermatitis is a short-term allergic contact dermatitis occurring in the skin of humans that have been infected by water-borne schistosomes, a type of flatworm. It is common in freshwater, brackis ...

Other organisms

* New World screwworm (''Cochliomyia''): causes myiasis

Ectoparasites

Head louse The head louse (''Pediculus humanus capitis'') is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feeding exclusively on human blood. Humans are the only known hosts of ...

(''Pediculus humanus capitis'') causes

pediculosis Pediculosis is an infestation of lice from the sub-order Anoplura, family Pediculidae. Accordingly, the infestation with head lice is named pediculosis capitis, while this with body lice, pediculosis corporis. Although ''pediculosis'' in humans ma ...

* Body louse (''Pediculus humanus humanus''): causes pediculosis *

Crab louse The crab louse or pubic louse (''Pthirus pubis'') is an insect that is an obligate ectoparasite of humans, feeding exclusively on blood. The crab louse usually is found in the person's pubic hair. Although the louse cannot jump, it can also liv ...

(''Pthirus pubis):'' causes

phthiriasis Pediculosis pubis (also known as "crabs" and "pubic lice") is an infestation by the pubic louse, ''Pthirus pubis'', a wingless insect which feeds on blood and lays its eggs (nits) on mainly pubic hair. Less commonly, hair near the anus, armpit ...

* Human botfly maggot (''Dermatobia hominis''): causes

myiasis Myiasis is the parasitic infestation of the body of a live animal by fly larvae (maggots) which grow inside the host while feeding on its tissue. Although flies are most commonly attracted to open wounds and urine- or feces-soaked fur, some spe ...

Flea Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, ...

(Siphonaptera): causes papular urticaria * Chigoe flea (''Tunga penetrans''): causes tungiasis *

Mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...

(Culicidae): causes papular urticaria *Bed bug (''

Cimex lectularius ''Cimex lectularius'' is a species of Cimicidae (bed bugs). Its primary hosts are humans, and it is one of the world's major "nuisance pests". Although bed bugs can be infected with at least 28 human pathogens, no studies have found that the i ...

''): causes papular urticaria *

Tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living ...

( Ixodoidea): causes

papular urticaria Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-last ...

* Chiggers (Trombiculidae): causes trombiculosis * Scabies mite (''Sarcoptes scabiei)'': causes

scabies Scabies (; also sometimes known as the seven-year itch) is a contagious skin infestation by the mite ''Sarcoptes scabiei''. The most common symptoms are severe itchiness and a pimple-like rash. Occasionally, tiny burrows may appear on the ski ...

Red mite ''Dermanyssus gallinae'' (also known as the red mite) is a haematophagous ectoparasite of poultry. It has been implicated as a vector of several major pathogenic diseases. Despite its common names, it has a wide range of hosts including sever ...

(''Dermanyssus gallinae''): causes gamasoidosis * Tropical fowl mite (''Ornithonyssus bursa''): causes gamasoidosis * Northern fowl mite (''Ornithonyssus sylviarum''): causes gamasoidosis *Tropical rat mite (''

Ornithonyssus bacoti ''Ornithonyssus bacoti'' (also known as the tropical rat mite) is a hematophagous parasite. It feeds on blood and serum from many hosts. ''O. bacoti'' can be found and cause disease on rats and wild rodents most commonly, but also small mammals ...

''): causes rodent mite dermatitis *Spiny rat mite ('' Laelaps echidnina''): causes rodent mite dermatitis *House mouse mite (''

Liponyssoides sanguineus ''Liponyssoides sanguineus'' is a species of mite that infests the house mouse (''Mus musculus''). It can transmit human disease, is associated with causing rodent mite dermatitis in humans and is noted for carrying '' Rickettsia akari'', which c ...

''): causes rodent mite dermatitis *

Demodex mite ''Demodex'' is a genus of tiny mites that live in or near hair follicles of mammals. Around 65 species of ''Demodex'' are known. Two species live on humans: ''Demodex folliculorum'' and ''Demodex brevis'', both frequently referred to as eyelash ...

: associated with

acne vulgaris Acne, also known as ''acne vulgaris'', is a long-term skin condition that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and po ...

and

rosacea Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often, the nose, cheeks, forehead, and chin are most involved. A red, enlarg ...

References

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