Human parasite

Last updated

Human parasites include various protozoa and worms.

Contents

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, 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

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 and is estimated to be from around 5900 BC. There are also claims of hookworm eggs from around 5000 BC in Brazil and large roundworm eggs from around 2330 BC in Peru. Tapeworm eggs have also been found present in Egyptian mummies dating 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

The first written records of parasites date from 3000 to 400 BC in Egyptian papyrus records. They identify parasites such as roundworms, Guinea worms, threadworms, and some tapeworms of unknown varieties. In ancient Greece, Hippocrates and Aristotle 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 as "hailstones" with Aristotle in the section about pig diseases in his book History of Animals . The cysts of the Echinococcus granulosus tapeworm 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 is dracunculiasis. 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

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 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." [3] :173 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 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, Romans, and Babylonians. [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 the flu, the common cold, and dysentery. However, several diseases such as Dracunculiasis (Guinea worm disease), Hookworm, Elephantiasis, Schistosomiasis, Malaria, and Amebiasis 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. [4] This disease was mentioned by Hippocrates in Greece along with Pliny the Elder, Galen, Aetius of Amida, and Paulus Aegineta of 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

The medieval Persian doctor Avicenna records the presence of several parasites in animals and in his patients including Guinea worm, threadworms, tapeworms, and the Ascaris worm. This followed a tradition of Arab medical writings spanning over 1000 years in the area near the Red Sea. However, the Arabs never made the connection between parasites and the diseases they caused. [3] :174 As with Greek and Roman texts, the Guinea worm is very well documented in Middle Eastern medical texts. Several Assyrian documents in the library of King Ashurbanipal refer to an affliction that has been interpreted as Guinea worm disease. [3] :174 In Egypt, the Ebers Papyrus contains one of the few references to hookworm disease in ancient texts. This disease does not have very specific symptoms and was vaguely mentioned. However vague the reference, it is one of the few that connect the disease to the hookworm parasite. [3] :174 Another documented disease is elephantiasis. Symptoms of this disease are highly visible, since it causes extreme swelling in the limbs, breasts, and genitals. A number of surviving statues indicate that Pharaoh Mentuhotep II is likely to have suffered from elephantiasis. This disease was well known to Arab physicians and Avicenna, who noted specific differences between elephantiasis and leprosy. [3] :175

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. [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

In India, the Charaka Samhita and Sushruta Samhita document malaria. These documents list the main symptoms as fever and enlarged spleens. [3] [ failed verification ] The Bhrigu Samhita from 1000 BCE makes the earliest reference to Amebiasis. The symptoms were given as bloody and mucosal diarrhea. [3]

Most common parasites

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

Parasitic DiseaseGlobal 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 Infections1,000,700

Commonly documented parasites

Endoparasites

Protozoa

Parasitic worms (helminths)

Guinea worm (Dracunculus) wrapped around a match stick Dracunculus medinensis.jpg
Guinea worm ( Dracunculus ) wrapped around a match stick

Parasitic flukes

Other organisms

Ectoparasites

Related Research Articles

<span class="mw-page-title-main">Intestinal parasite infection</span> Condition in which a parasite infects the gastro-intestinal tract of humans and other animals

An intestinal parasite infection is a condition in which a parasite infects the gastro-intestinal tract of humans and other animals. Such parasites can live anywhere in the body, but most prefer the intestinal wall.

<span class="mw-page-title-main">Filariasis</span> Parasitic disease caused by a family of nematode worms

Filariasis, is a filarial infection caused by parasitic nematodes (roundworms) spread by different vectors. They are included in the list of neglected tropical diseases.

<span class="mw-page-title-main">Parasitology</span> Study of parasites, their hosts, and the relationship between them

Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life. This means it forms a synthesis of other disciplines, and draws on techniques from fields such as cell biology, bioinformatics, biochemistry, molecular biology, immunology, genetics, evolution and ecology.

<span class="mw-page-title-main">Helminthiasis</span> Any macroparasitic disease caused by helminths

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 broadly classified into tapeworms, flukes, and roundworms. They often live in the gastrointestinal tract of their hosts, but they may also burrow into other organs, where they induce physiological damage.

<span class="mw-page-title-main">Dracunculiasis</span> Infection by the Guinea worm

Dracunculiasis, also called Guinea-worm disease, is a parasitic infection by the Guinea worm, Dracunculus medinensis. A person becomes infected by drinking water contaminated with Guinea-worm larvae that reside inside copepods. Stomach acid digests the copepod and releases the Guinea worm, which penetrates the digestive tract and escapes into the body. Around a year later, the adult female migrates to an exit site – usually the lower leg – and induces an intensely painful blister on the skin. Eventually, the blister bursts, creating a painful wound from which the worm gradually emerges over several weeks. The wound remains painful throughout the worm's emergence, disabling the affected person for the three to ten weeks it takes the worm to emerge.

<span class="mw-page-title-main">Helminthic therapy</span> Deliberate infestation with parasitic worms

Helminthic therapy, an experimental type of immunotherapy, is the treatment of autoimmune diseases and immune disorders by means of deliberate infestation with a helminth or with the eggs of a helminth. Helminths are parasitic worms such as hookworms, whipworms, and threadworms that have evolved to live within a host organism on which they rely for nutrients. These worms are members of two phyla: nematodes, which are primarily used in human helminthic therapy, and flat worms (trematodes).

Acariasis is an infestation with mites.

<span class="mw-page-title-main">Lymphatic filariasis</span> Medical condition

Lymphatic filariasis is a human disease caused by parasitic worms known as filarial worms. Usually acquired in childhood, it is a leading cause of permanent disability worldwide, impacting over a hundred million people and manifesting itself in a variety of severe clinical pathologies While most cases have no symptoms, some people develop a syndrome called elephantiasis, which is marked by severe swelling in the arms, legs, breasts, or genitals. The skin may become thicker as well, and the condition may become painful. Affected people are often unable to work and are often shunned or rejected by others because of their disfigurement and disability.

<i>Dermanyssus gallinae</i> Species of mite

Dermanyssus gallinae 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 several species of wild birds and mammals, including humans, where the condition it causes is called gamasoidosis. In both size and appearance, it resembles the northern fowl mite, Ornithonyssus sylviarum.

<span class="mw-page-title-main">Ancylostomiasis</span> Medical condition

Ancylostomiasis is a hookworm disease caused by infection with Ancylostoma hookworms. The name is derived from Greek ancylos αγκύλος "crooked, bent" and stoma στόμα "mouth".

Parasitic worm, also known as helminth, is large macroparasite.

<span class="mw-page-title-main">Hookworm vaccine</span>

Hookworm vaccine is a vaccine against hookworm. No effective vaccine for the disease in humans has yet been developed. Hookworms, parasitic nematodes transmitted in soil, infect approximately 700 million humans, particularly in tropical regions of the world where endemic hookworms include Ancylostoma duodenale and Necator americanus. Hookworms feed on blood and those infected with hookworms may develop chronic anaemia and malnutrition. Helminth infection can be effectively treated with benzimidazole drugs, and efforts led by the World Health Organization have focused on one to three yearly de-worming doses in schools because hookworm infections with the heaviest intensities are most common in school-age children. However, these drugs only eliminate existing adult parasites and re-infection can occur soon after treatment. School-based de-worming efforts do not treat adults or pre-school children and concerns exist about drug resistance developing in hookworms against the commonly used treatments, thus a vaccine against hookworm disease is sought to provide more permanent resistance to infection.

<span class="mw-page-title-main">Gamasoidosis</span> Dermatitis caused by avian mites

Gamasoidosis, also known as dermanyssosis, is a frequently unrecognized form of dermatitis, following human infestation with avian mites of the genera Dermanyssus or Ornithonyssus. It is characterized by pruritic erythematous papules, macules and urticaria, with itching and irritation resulting from the saliva the mites secrete while feeding. These bites are commonly found around the neck and areas covered by clothing, but can be found elsewhere on the body. The avian mite Dermanyssus gallinae can also infest various body parts, including the ear canal and scalp.

Bertielliasis is the infection of Bertiella, a cestode tapeworm parasite that primarily infects nonhuman primates, rodents and Australian marsupials. Occasionally, human infections have been documented by one of two species: Bertiella studeri, or Bertiella mucronata. Of 29 different Bertiella species, only these two can infect humans.

<i>Ornithonyssus bacoti</i> Species of mite

Ornithonyssus bacoti 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 and humans when other hosts are scarce. Outbreaks tend to occur in older, less maintained buildings. The mite, however, can travel several hundred feet on its own if necessary to find a host and can survive for extended periods of time without a host. This, along with the nonspecific dermatitis it causes, can prevent accurate and fast diagnosis of rat mite dermatitis. The scarcity of reports, due in part to misdiagnosis and also the mildness of its symptoms, makes the disease seem less common than it is. The tropical rat mite can be found in both temperate and tropical regions or rather all continents except the Arctic and Antarctic.

<span class="mw-page-title-main">Mites of domestic animals</span> Type of parasite of domestic animals

Mites that infest and parasitize domestic animals cause disease and loss of production. Mites are small invertebrates, most of which are free living but some are parasitic. Mites are similar to ticks and both comprise the order Acari in the phylum Arthropoda. Mites are highly varied and their classification is complex; a simple grouping is used in this introductory article. Vernacular terms to describe diseases caused by mites include scab, mange, and scabies. Mites and ticks have substantially different biology from, and are classed separately from, insects. Mites of domestic animals cause important types of skin disease, and some mites infest other organs. Diagnosis of mite infestations can be difficult because of the small size of most mites, but understanding how mites are adapted to feed within the structure of the skin is useful.

Rodent mite dermatitis is an often unrecognized ectoparasitosis occurring after human contact with haematophagous mesostigmatid mites that infest rodents, such as house mice, rats and hamsters. The condition is associated with the tropical rat mite, spiny rat mite and house mouse mite which opportunistically feed on humans. Rodent mites are capable of surviving for long periods without feeding and travelling long distances when seeking hosts. Cases have been reported in homes, libraries, hospitals and care homes. A similar condition, known as gamasoidosis, is caused by avian mites.

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, and hygiene. In humans, infections are caused by two main species of roundworm, belonging to the genera Ancylostoma and Necator. In other animals the main parasites are species of Ancylostoma. Hookworm is closely associated with poverty because it is most often found in impoverished areas, and its symptoms promote poverty through the educational and health effects it has on children. It is the leading cause of anemia and undernutrition in developing countries, while being one of the most commonly occurring diseases among poor people. Hookworm thrives in areas where rainfall is sufficient and keeps the soil from drying out, and where temperatures are higher, making rural, coastal areas prime conditions for the parasite to breed.

Wolves may suffer from various pathogens, both viral and bacterial, and parasite, both external and internal. Parasitic infection in wolves is of particular concern to people. Wolves can spread them to dogs, which in turn can carry the parasites to humans. In areas where wolves inhabit pastoral areas, the parasites can be spread to livestock.

<span class="mw-page-title-main">Cat worm infections</span> Worm infections in cats

Cat worm infections, the infection of cats (Felidae) with parasitic worms, occur frequently. Most worm species occur worldwide in both domestic and other cats, but there are regional, species and lifestyle differences in the frequency of infestation. According to the classification of the corresponding parasites in the zoological system, infections can be divided into those caused by nematode and flatworms - in the case of the latter, mainly cestoda and trematoda - while other strains are of no veterinary significance. While threadworms usually do not require an intermediate host for their reproduction, the development cycle of flatworms always proceeds via alternate hosts.

References

  1. "Krumhardt, Barbera, PhD. Human Parasites. 8 October 2008". Archived from the original on 16 December 2008. Retrieved 17 December 2008.
  2. "Parasites – How they enter our body and ten precautions to avoid an infection".
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 Cox, Francis E. G. "History of human parasitic diseases." Infectious Disease Clinics of North America June 2004
  4. Kuchenmeister, F. Animal and vegetableparasites. London: The Sydenham Society, 1857
  5. "One Million Deaths by Parasites | Speaking of Medicine". 16 January 2015. Retrieved 18 September 2016.
  6. Greenaway, C. "Dracunculiasis". Canadian Medical Association Journal (Feb 2004)