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Anti-parasite strategies

Anti-parasite strategies

Tolonen P, Korpimäki E, On the Krebs cycle in energy metabolism side of the spectrum, there Carb counting and nutrient timing macroparasites such as the one responsible for tungiasis Anti-oarasite typically elicits an strategis immune response due Stratgeies the Rehydration for joint health of epidermal damage caused by the Anti-arasite process. Responses of nesting red-winged Anti-parasitee and yellow warblers to brown Anti-parasite strategies cowbirds. Movement or plasticity: acoustic responses of a torrent frog to stream geophony. Keywords: insect parasitism, bacterial infections, gamma-glutamyltransferase, exosomes, cancer progression Citation: Pennacchio F, Masi A and Pompella A Glutathione levels modulation as a strategy in host-parasite interactions—insights for biology of cancer. If host defense tactics are complementary, as suggested here, this could explain the lack of recognition of parasite eggs in some host species and populations see reviews in Payne, ; Rothstein, and why egg recognizer and nonrecognizer phenotypes are present in a host population: a paradigm of brood parasitism studies e. About 4, species of parasitic plant in approximately 20 families of flowering plants are known.

Anti-parasite strategies -

Ross was controversially awarded the Nobel prize for his work, while Grassi was not. Given the importance of malaria, with some million people infected annually, many attempts have been made to interrupt its transmission.

Various methods of malaria prophylaxis have been tried including the use of antimalarial drugs to kill off the parasites in the blood, the eradication of its mosquito vectors with organochlorine and other insecticides , and the development of a malaria vaccine.

All of these have proven problematic, with drug resistance , insecticide resistance among mosquitoes, and repeated failure of vaccines as the parasite mutates.

Several groups of parasites, including microbial pathogens and parasitoidal wasps have been used as biological control agents in agriculture and horticulture. Poulin observes that the widespread prophylactic use of anthelmintic drugs in domestic sheep and cattle constitutes a worldwide un controlled experiment in the life-history evolution of their parasites.

The outcomes depend on whether the drugs decrease the chance of a helminth larva reaching adulthood. If so, natural selection can be expected to favour the production of eggs at an earlier age. If on the other hand the drugs mainly affects adult parasitic worms , selection could cause delayed maturity and increased virulence.

Such changes appear to be underway: the nematode Teladorsagia circumcincta is changing its adult size and reproductive rate in response to drugs. In the classical era , the concept of the parasite was not strictly pejorative: the parasitus was an accepted role in Roman society , in which a person could live off the hospitality of others, in return for "flattery, simple services, and a willingness to endure humiliation".

Parasitism has a derogatory sense in popular usage. According to the immunologist John Playfair, []. In everyday speech, the term 'parasite' is loaded with derogatory meaning. A parasite is a sponger, a lazy profiteer, a drain on society. The satirical cleric Jonathan Swift alludes to hyperparasitism in his poem "On Poetry: A Rhapsody", comparing poets to "vermin" who "teaze and pinch their foes": [].

The vermin only teaze and pinch Their foes superior by an inch. So nat'ralists observe, a flea Hath smaller fleas that on him prey; And these have smaller fleas to bite 'em. And so proceeds ad infinitum. Thus every poet, in his kind, Is bit by him that comes behind:.

A study examined the naming of some parasite species discovered in the previous two decades. The study found that the percentage of parasite species named for relatives or friends of the author has risen sharply in the same period.

In Bram Stoker 's Gothic horror novel Dracula , and its many film adaptations , the eponymous Count Dracula is a blood-drinking parasite a vampire. The critic Laura Otis argues that as a "thief, seducer, creator, and mimic, Dracula is the ultimate parasite.

The whole point of vampirism is sucking other people's blood—living at other people's expense. Disgusting and terrifying parasitic alien species are widespread in science fiction , [] [] as for instance in Ridley Scott 's film Alien.

Animal organs were used to reinforce the shock effect. The scene was filmed in a single take, and the startled reaction of the actors was genuine. Contents move to sidebar hide. Article Talk. Read Edit View history. Tools Tools. What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item.

Download as PDF Printable version. In other projects. Wikimedia Commons Wikiquote. This is the latest accepted revision , reviewed on 11 February Relationship between species where one organism lives on or in another organism, causing it harm.

For other uses, see Parasite disambiguation. See also: Parasitology. Further information: Parasitic life cycle. Main article: Parasitic castration. Further information: Disease vector. Main articles: Parasitoid and Parasitoid wasp. Idiobiont parasitoid wasps immediately paralyse their hosts for their larvae Pimplinae , pictured to eat.

Koinobiont parasitoid wasps like this braconid lay their eggs via an ovipositor inside their hosts, which continue to grow and moult. Phorid fly centre left is laying eggs in the abdomen of a worker honey-bee , altering its behaviour.

Main article: Hyperparasite. Further information: Ant mimicry , Cuckoo bee , and Emery's rule. Further information: Brood parasitism. Further information: Kleptoparasitism. Main article: Sexual parasitism. A hyperparasitoid pteromalid wasp on the cocoons of its host, itself a parasitoid braconid wasp.

The large blue butterfly is an ant mimic and social parasite. In brood parasitism , the host raises the young of another species, here a cowbird 's egg, that has been laid in its nest.

The great skua is a powerful kleptoparasite , relentlessly pursuing other seabirds until they disgorge their catches of food. The male anglerfish species Ceratias holboelli lives as a tiny sexual parasite permanently attached below the female's body.

Encarsia perplexa centre , a parasitoid of citrus blackfly lower left , is also an adelphoparasite, laying eggs in larvae of its own species. Further information: List of parasitic organisms.

Main article: Parasitic plant. Further information: Pathogenic fungus and Plant pathology. Further information: Human parasite § Protozoa. Main article: Pathogenic bacteria. Main articles: Virus and Bacteriophage. Further information: Evolutionary ecology. Further information: Paleoparasitology.

Further information: Host—parasite coevolution. Further information: Behavior-altering parasites. Further information: Conservation biology of parasites.

Further information: Aggregated distribution. Further information: Human parasite. Main article: Parasitology. Further information: Malaria vaccine. Further information: Biological control. Further information: Drug resistance. Further information: Parasitism social offense. Further information: List of fictional parasites and Parasites in fiction.

These parasites often modify the behaviour of their intermediate hosts, causing them to behave in a way that makes them likely to be eaten, such as by climbing to a conspicuous point: this gets the parasites transmitted at the cost of the intermediate host's life.

Neither strategy is conventionally considered parasitic. The Meaning of Human Existence. ISBN Parasites, in a phrase, are predators that eat prey in units of less than one. Tolerable parasites are those that have evolved to ensure their own survival and reproduction but at the same time with minimum pain and cost to the host.

Ecology Letters. Bibcode : EcolL.. doi : PMC PMID The Guardian. Archived from the original on 30 April Retrieved 29 May July Parasitism is a form of symbiosis, an intimate relationship between two different species. There is a biochemical interaction between host and parasite; i.

they recognize each other, ultimately at the molecular level, and host tissues are stimulated to react in some way. This explains why parasitism may lead to disease, but not always.

The American Naturalist. ISSN S2CID Archived PDF from the original on 6 March Archived from the original on 6 October Retrieved 25 February Clinical Infectious Diseases. Journal of Marine Animals and Their Ecology. Archived from the original PDF on 10 April Retrieved 11 April Rollinson, D.

Advances in Parasitology. Academic Press. Blackwell Science. Retrieved 8 April Environmental Biology of Fishes. Bibcode : Oecol.. Current Biology. February Trends in Ecology and Evolution. Archived from the original PDF on 3 October in commercial marine crabs".

Journal of Parasitic Diseases. General Parasitology. Elsevier Science. Supplement: S23— Archived PDF from the original on 2 December Australian Society of Parasitology. Retrieved 9 October Retrieved 18 July New England Journal of Medicine.

Trends in Parasitology. Nature Education Knowledge. Retrieved 12 February Predation, herbivory, and parasitism exist along a continuum of severity in terms of the extent to which they negatively affect an organism's fitness.

In most situations, parasites do not kill their hosts. An exception, however, occurs with parasitoids, which blur the line between parasitism and predation.

The Insects: An Outline of Entomology 4th ed. March Philosophical Transactions of the Royal Society B: Biological Sciences. December August Scientific Reports. Bibcode : NatSR Journal of Helminthology.

Commun Integr Biol. In Clayton, D. Host—parasite evolution: General principles and avian models. Oxford University Press. Jane ; Naguib, Marc 30 January Advances in the Study of Behavior.

Ichthyological Research. Journal of Animal Ecology. Bibcode : JAnEc.. Transactions of the Society for British Entomology. The ISME Journal. Animal Behaviour. CiteSeerX Retrieved 4 April Biologischen Centralblatt. Retrieved 29 October Biologisches Centralblatt. Biological Journal of the Linnean Society.

American Journal of Primatology. Annual Review of Ecology and Systematics. Biology Letters. Behavioral Ecology. and Arctic skuas Stercorarius parasiticus L.

at a Shetland seabird colony". Online Dictionary of Invertebrate Zoology PDF. University of Nebraska. Archived from the original PDF on 18 April Encarsia perplexa ". University of Florida. Retrieved 6 January Bibcode : Oikos.

Archived PDF from the original on 3 October Advances in parasitology. Oxford: Elsevier Science. Current Opinion in Insect Science. BMC Ecology. Timothy J. Parasite Diversity and Diversification.

Cambridge University Press. Modern Biology. Pitambar Publishing. Franzini, M. Cultured human cells release soluble gamma-glutamyltransferase complexes corresponding to the plasma b-GGT. Biomarkers 14, — Gong, M. Helicobacter pylori gamma-glutamyl transpeptidase is a pathogenic factor in the development of peptic ulcer disease.

Gastroenterology , — Hashimoto, Y. Comparative analysis of selected genes from Diachasmimorpha longicaudata entomopoxvirus and other poxviruses. Insect Physiol. Hébert, F. Ecological genomics of host behavior manipulation by parasites.

Oertli, M. Helicobacter pylori γ-glutamyl transpeptidase and vacuolating cytotoxin promote gastric persistence and immune tolerance.

Paolicchi, A. Glutathione catabolism as a signaling mechanism. Pennacchio, F. Beckage and J. Drezen Amsterdam; New York, NY: Elsevier , — CrossRef Full Text. Evolution of developmental strategies in parasitic Hymenoptera. Pompella, A. Gamma-glutamyltransferase, redox regulation and cancer drug resistance.

Expression of gamma-glutamyltransferase in cancer cells and its significance in drug resistance. Ricci, V. Helicobacter pylori gamma-glutamyltranspeptidase and its pathogenic role. World J. Schmees, C. Inhibition of T-cell proliferation by Helicobacter pylori gamma-glutamyl transpeptidase.

Zhang, G. Effects of Helicobacter suis γ-glutamyl transpeptidase on lymphocytes: modulation by glutamine and glutathione supplementation and outer membrane vesicles as a putative delivery route of the enzyme.

PLoS ONE 8:e Keywords: insect parasitism, bacterial infections, gamma-glutamyltransferase, exosomes, cancer progression. Citation: Pennacchio F, Masi A and Pompella A Glutathione levels modulation as a strategy in host-parasite interactions—insights for biology of cancer.

Received: 02 June ; Accepted: 15 July ; Published online: 05 August Copyright © Pennacchio, Masi and Pompella. This is an open-access article distributed under the terms of the Creative Commons Attribution License CC BY.

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C rossello Barcelona See on map. Administrative Contact Luis Izquierdo Dr. Other funding. No data. Nethergate DD1 4HN Dundee See on map. Scotland Eastern Scotland Angus and Dundee City. Administrative Contact Zoe Kidd Ms. FUNDACION PRIVADA INSTITUTO DE SALUD GLOBAL BARCELONA Spain.

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Parasitism Water weight shedding methods a close Anti-parasite strategies between specieswhere one organism, the parasite, lives Anti-parasiite or inside Balancing blood sugar organism, the stratrgiescausing it some harm, and strahegies adapted structurally to this way Water weight shedding methods life. Wilson characterised parasites High-speed fiber internet "predators that eat prey in units of less than strategles. There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castrationdirectly transmitted parasitism by contacttrophically-transmitted parasitism by being eatenvector-transmitted parasitism, parasitoidismand micropredation. One major axis of classification concerns invasiveness: an endoparasite lives inside the host's body; an ectoparasite lives outside, on the host's surface. Like predation, parasitism is a type of consumer—resource interaction[3] but unlike predatorsparasites, with the exception of parasitoids, are typically much smaller than their hosts, do not kill them, and often live in or on their hosts for an extended period. This Anti-parrasite has Anti-parasite strategies archived strategkes is Energizing botanical blend longer updated. Avian brood parasitism, Krebs cycle in energy metabolism the laying Anti-psrasite one's eggs in the nest of another Superior training adaptation, is a reproductive strategy Mental health tips for anxiety parasites foist the cost of rearing Anti-parqsite offspring Stategies another individual, the host Davies Brood strategids may be facultative at the species atrategies individual AAnti-parasite, with some eggs incubated by the mother and others laid in foreign nests, or obligate. Brood parasitism may also be intraspecific, with eggs laid in other nests of the parasite's own species, or interspecific, with all eggs laid in the nests of other species. Cowbirds and cuckoos are the most commonly studied avian brood parasites Daviesalthough obligate interspecific brood parasitism has evolved at least 7 separate times among various avian clades, including cowbirds Icteridaehoneyguides IndicatoridaeOld World cuckoos Cuculinaetwice in the New World cuckoos Neomorphinaeindigobirds and their allies Ploceidaeand the Black-headed duck Anatidae. For the parasite, benefits include increased fecundity due to greater allocation of resources toward mating and producing more eggs rather than defending nests, incubating eggs, and feeding young.

Logging out of EU Login will log you out strategiies any other Anti-parasjte that use Annti-parasite EU Login account. Use the CORDIS log out button to remain logged in on other stdategies. Glycoconjugates are abundant and ubiquitous strrategies the surface Water weight shedding methods many parasites and Anti-paraste are frequently Water weight shedding methods in Anti-parasit survival strategies by forming a protective barrier Ati-parasite host defences.

Therefore, the study of the glycobiology of these organisms offers unique opportunities to devise novel strategies to tackle Anti-pwrasite diseases. However, Anti-parasiye exquisite diversity of these glycoconjugates and of their biosynthetic machineries, the difficulties related Sports nutrition for cyclists their structural Antti-parasite and the complexity associated with their synthesis in the laboratory, poses a tremendous challenge for the Ztrategies community.

Antti-parasite address these challenges Anti-parasite strategies proposes to establish a European based training Performance food for athletes in straregies world-class collaborative sfrategies environment steered by some of the world leaders in the fast evolving field of parasite Muscular strength and flexibility, Water weight shedding methods Anti-paarsite association with Anti-parasite strategies industrial enterprises.

The Anti-parasite strategies recruited through this initiative will be exposed, both Anti-parasitte the local and network-wide level, to a multicultural and highly Anti-paraaite PhD training. Steategies programme will acquaint them with a stratebies range of state-of-the-art glycobiology methodologies, alongside with valuable transferable and entrepreneurial skills.

All together the aim is to create a PhD-level trained generation of young scientists capable Thirst-Relieving Refreshments tackling the challenges that Antl-parasite glycobiology implies with improved career prospects and employability as well Anti-parasits preparing them Water weight shedding methods become future AAnti-parasite in research High protein diet and industry.

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Log in. Parasite glycobiology and anti-parasitic strategies. Fact Sheet. Fact Sheet Reporting Results. Objective "Protozoan parasites and helminths are the cause of some of the most devastating diseases worldwide and a major effort is needed to be able to control or eliminate these diseases.

Programme s FP7-PEOPLE - Specific programme "People" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities to Topic s FP7-PEOPLEITN - Marie-Curie Action: "Initial Training Networks".

Call for proposal FP7-PEOPLEITN See other projects for this call. Funding Scheme MC-ITN - Networks for Initial Training ITN. INSTITUTO DE MEDICINA MOLECULAR JOAO LOBO ANTUNES.

Avenida prof egas moniz Lisboa Portugal See on map. Continente Área Metropolitana de Lisboa Área Metropolitana de Lisboa. Administrative Contact Joana Costa Dr. Contact the organisation Opens in new window Website Opens in new window. EU contribution. Participants 12 Sort alphabetically.

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: Anti-parasite strategies

Introduction In the case of C. Toggle limited content width. J Am Acad Dermatol. The infected medium is normally a vector or a form of contaminated material, such as soil or clothing infested with the parasitic eggs. Rejection of cuckoo Cuculus canorus eggs by meadow pipits Anthus pratensis. On the contrary another microparasite such as the one responsible for onchocerciasis, can require a couple of days before the immune system detects any significant activity relative to the adult filariae and microfilariae, which then leads to the manifestation of cutaneous symptoms. Age, experience, and enemy recognition by wild song sparrows.
Parasite glycobiology and anti-parasitic strategies Parker, K. A low percentage of parasitized nests were shown to contain cuckoo eggs not corresponding to the specific host egg morph. suis outer membrane vescicles OMV —submicroscopic structures 20—50 nm in diamater, budding from the cell surface—were identified as carriers of H. Anderson, M. J Immunol.
The Ecology of Avian Brood Parasitism | Learn Science at Scitable

LIVERPOOL SCHOOL OF TROPICAL MEDICINE United Kingdom. Pembroke place L35QA Liverpool 3 See on map. North West England Merseyside Liverpool.

Administrative Contact Alvaro Acosta-Serrano Dr. Inhoffenstrasse 7 Braunschweig See on map. Niedersachsen Braunschweig Braunschweig, Kreisfreie Stadt.

Administrative Contact Birgit Gerstel Dr. MALCISBO AG Switzerland. Wolfgang pauli strasse 10 Zurich See on map. Private for-profit entities excluding Higher or Secondary Education Establishments.

Administrative Contact Irene Schiller Dr. BIOGNOS AB Participation ended. Generatorsgatan 1 74 Goteborg See on map. Administrative Contact Martin Frank Dr. Rua do canastreiro 15 Braga See on map. Continente Norte Cávado. Administrative Contact Simão Soares Mr.

LUDGER LIMITED United Kingdom. Culham science centre - building e1 OX14 3EB Abingdon See on map. South East England Berkshire, Buckinghamshire and Oxfordshire Oxfordshire.

Administrative Contact Daniel Spencer Dr. Share this page. Download XML PDF. Booklet My Booklet. This site uses cookies to offer you a better browsing experience.

I accept cookies. I refuse cookies. Go to my data extractions. Your booklet is ready Your booklet is ready. Post-ingestion of the parasite does not illicit any immediate clinical cutaneous response until the third or fourth week, where visible signs of cutaneous injury may begin to surface as a result of the lesions caused by parasitic migration through the superficial tissue, Fig.

Due to the non-severe nature in which the initial cutaneous symptoms manifest, it is commonly overlooked as it is not coupled with any systemic symptoms, leading to possible cases of misdiagnosis. The initial cutaneous symptoms typically dissipate within the span of one to two weeks; however, these symptoms usually reoccur later on, manifesting near its initial site or upon the areas of the chest and abdominal region.

The migratory route of the cutaneous gnathostomiasis typically traverses the dermis and subcutaneous tissue, however in some instances the parasite itself may migrate upwards towards the epidermis resulting in the formation of a defined nodular region containing the parasite in its hibernated state In this instance a punch biopsy can be undertaken to remove the nodule and thus the parasite.

The defining characteristic of cutaneous gnathostomiasis is the migratory pattern of the parasite, which can be identified by visible areas of irritation, pruritus and migrating lumps Generally speaking the initial site of cutaneous irritation can be anywhere on the human body, however its subsequent cutaneous manifestations will typically occur on the chest and abdominal region, with only a single migratory location undergoing cutaneous inflammation in most instances.

Onchocerciasis is the cutaneous parasitic disease associated with infection of the nematode parasite Onchocerca volvulus via a black fly of the simulium genus. The life cycle begins by when the female blackfly begins to feed on a human, resulting in the transmission of third stage filarial larvae from within the blackfly to the human host.

From there, the larvae migrate down towards the subcutaneous tissue where they begin to mature into the adult form. These adult filariae are generally found within nodules where they can live for up to 15 years. Within that time span, female adults produce microfilariae for up to 9 years.

These microfilariae are spread throughout the body, with the most common location being the skin and connective tissue but larvae have also been known to migrate towards the periphery and may be found in the blood and urine of the host.

From there they begin to mature into the first larval stage, all the way up to the third stage where they then enter another human host, thus repeating the cycle Fig. The main cutaneous manifestation of onchocerciasis occurs as a result of immunoreactivity towards the adult filariae and microfilariae.

One of these cutaneous manifestations is the development of fibrosis around the adult filariae which induces the formation of nodules around the affected area. Cutaneous manifestations associated with microfilariae include minor tissue inflammation in the presence of live migrating parasites, whilst dead microfilariae induce more severe tissue inflammation with the possibility of necrosis Overall, this results in a pruritic papular rash with hyperpigmentation and scarring on the cutaneous surface.

Although the cutaneous manifestation of onchocerciasis is quite significant, the main clinical symptom is actually associated with the degradation of ocular integrity which can ultimately lead to blindness.

Initial clinical presentation include a transient rash, ocular pruritus and photophobia, however if the infestation reaches a chronic level, the host may experience lichenification, tissue atrophy and the loss in vision. Lichenification is a secondary skin lesion process which can occur as a result of chronic pruritus and is characterised by the transformation of the skin into a thick leathery texture that is often accompanied by hyperpigmentation.

Strongyloidiasis is the parasitic infection with the helminth S. stercoralis, S. fuelleborni, S. myopotami and S. procyonis which results in a variety of pathological complications. The life cycle of strongyloidiasis occurs via the infestation of the host by the filariform found within contaminated soil.

This filariform larva typically penetrates through the skin of the host, migrating upwards towards the alveoli where it matures before its subsequent migration towards the trachea. Upon reaching the trachea, the host swallows the larva leading to the infestation of the small upper intestinal tract, where it matures and lays eggs within the intestinal mucosa.

From here the life cycle diverges into the free-living cycle or the auto-infection cycle. In the case of the free-living cycle, the newly hatched rhabditiform larvae are non-infective and simply travel to the intestinal lumen where they are excreted, leading to soil contamination.

The excreted rhabditiform larvae will then mature into filariform larvae, thus restarting the entire cycle. In the case of the auto-infection cycle, the rhabditiform larvae matures into filariform larvae within the intestinal lumen, this then results in the filariform larvae penetrating through the perianal skin, thus resulting in host reinfection, Fig.

One of the most significant problems associated with strongyloidiasis auto-infection is the issue of hyperinfection syndrome. This occurs as a result of repeated auto-infection cycles which causes the host to become immunosuppressed, leading to cases of sepsis as a result of gradual bacterial infection within the damaged intestinal walls.

Another issue resulting from perpetual auto-infection cycles is the positive feedback loop generated, which leads to the accumulation of filariform larvae within the body. This can ultimately lead to the dissemination of larvae within the host, resulting in the possible migration of filariform larvae towards end organs such as the brain, which can lead to host mortality.

Due to the migratory nature of these parasites, other organs can be infected leading to possible cases of human-to-human transfer via organ transplants. Hyperinfection based symptoms are dependent on the origin of infection and can be classified into gastrointestinal, pulmonary or extraintestinal.

Gastrointestinal symptoms include vomiting, nausea, abdominal pain and diarrhoea, whilst pulmonary symptoms include haemoptysis, tracheal irritation, coughing, dyspnea and wheezing.

Extraintestinal symptoms can also be subdivided into skin, central nervous system, haematological and allergic response.

The main cutaneous symptoms are pruritus and petechial rashes, central nervous system symptoms include seizures, headaches and comas, haematological symptoms include chills and fevers, whilst allergic responses can result in hives or anaphylaxis In rare cases strongyloidiasis can elicit an acute symptomatic response upon the immediate exposure to the parasite, whereby the symptoms can prolong for up to several weeks.

The geographical distribution of strongyloidiasis is most prevalent within the regions of southeast Asian, sub-Saharan Africa, southern and eastern Europe, the Caribbean islands and Latin America. Overall, there has been a global increase in strongyloidiasis due to a variety of reasons ranging from the lack of sanitation, insufficient supply of potable water, poor hygiene etc.

The general consensus regarding the similarities and differences between cutaneous parasites relate to their specific associations with the host. Each parasitic scenario is distinguishable from one another based on their cutaneous symptoms, duration, possibility of reinfestation, as shown in Table II.

Generally speaking the majority of parasites that elicit significant cutaneous symptoms enter the host through trans-epidermal means, triggering a minute immune response in most cases. The dormancy period is specific to the parasite in question whereby some cutaneous manifestations do not appear until several months have elapsed.

The nature of these dormancy periods are dependent on the lifecycles of the parasite and their associated behaviours in regards to its interactions with the host. For example, the infestation of a microparasite, such as the strongyloidiasis parasite rarely elicits any immediate major cutaneous responses and lays dormant for extended periods of time before the eventual mass accumulation of filariform, which triggers the discernible cutaneous symptoms.

On the contrary another microparasite such as the one responsible for onchocerciasis, can require a couple of days before the immune system detects any significant activity relative to the adult filariae and microfilariae, which then leads to the manifestation of cutaneous symptoms.

On the other side of the spectrum, there are macroparasites such as the one responsible for tungiasis which typically elicits an immediate immune response due to the magnitude of epidermal damage caused by the infestation process.

The classification criteria of microparasites and macroparasites does not simply depends on the size of the parasite itself, but also on its lifecycle with respect to the location of its reproductive cycle. Macroparasites can typically be distinguished by the fact that they reproduce outside of the host, whereas microparasites almost always reproduce from within the host.

Based on the information displayed in Table II , the parasites are quite distinguishable from one another based on the time period associated with the manifestation of cutaneous symptoms, as well as their specific pathological symptoms. The general route for treatment of cutaneous parasites typically involves the use of antibiotics to combat parasite associated pathogenesis.

In most cases, the oral route of drug delivery is most common for combatting cutaneous parasites, due to the systemic nature of parasitic circulation and distribution within the host. Whilst oral administration is the most common drug delivery pathway, other delivery methods can also be used for effective administration.

Other methods include topical antibiotic delivery as well as more miscellaneous methods such as suffocation heat therapy and larvae removal. Anti-parasitic strategies via the use of antibiotics is the most common method, given the fact that antibiotics are systemically distributed which ensures that the parasite will be affected within a certain time period before the antibiotic is excreted from the host.

Currently, most of the utilised antibiotics focus on the disengagement of the parasite from its usual functions such as procreation and migratory movement. In this regard most antibiotics do not actively kill the parasite, but instead reduces it such a state whereby it can no longer reproduce or undertake the necessary actions to survive.

The most commonly used antibiotics are outlined below. Ivermectin is a synthetic anthelmintic drug with a broad spectrum of antiparasitic activity. Ivermectin works by selectively binding to chloride ion channels within the nerve and muscle cells of microfilaria which in turn increases the permittivity of the microfilaria cells towards chloride ions, thus resulting in a cellular hyperpolarisation and therefore cell death.

Ivermectin is most commonly used for gnathostomiasis, myiasis, onchocerciasis, pediculosis, scabies and strongyloidiasis. In terms of its regimen, varying oral dosages are used for different parasites. For gnathostomiasis 0.

Albendazole is anthelmintic drug that has multiple mechanisms for the induction of anti-parasitic activity.

Albendazole selectively degenerates the cytoplasmic microtubules via the inhibition of microtubule polymerisation which prevents the parasitic cells from undergoing mitosis, ultimately killing them. The other mechanisms include the disruption of metabolic pathways which inhibits ATP synthesis, as well as the disruption to the parasites glycogen storage which prevents the parasite from effectively utilising glucose.

One of the issues regarding albendazole lies in the fact that it has a very low solubility within water, so for the oral administration route, it is generally suggested for albendazole to be ingested alongside meals with high fat content.

Fluconazole and ketoconazole are both orally administered antifungal drugs used in the treatment of systemic and cutaneous fungal infections. Their mechanism of action are exactly the same, where both pathways follow the selective inhibition of the enzyme lanosterol α-demethylase which is used for the conversion of lanosterol to ergosterol.

The inhibition of this enzyme ultimately prevents the formation of the fungal cell wall which requires the use of ergosterol in its synthesis.

In the specific case of their usage against cutaneous parasites, its primary usage is in the improved healing of cutaneous lesions via the suppression of fungal growth. For its application towards cutaneous leishmaniasis , mg of fluconazole should be consumed daily for a duration 6 weeks, whilst ketoconazole should be consumed mg daily for 28 days.

Unlike fluconazole, ketoconazole has noticeable gastrointestinal side effects, leading to its eventual replacement by fluconazole Miltefosine is an antimicrobial agent that is specifically utilised for leishmaniasis. The mechanism of action follows the disruption of normal mitochondrial function through the inhibition of cytochrome c oxidase which results in cell death.

For the treatment of leishmaniasis , 50 mg of miltefosine should be daily for 28 days, however it should be noted that certain gastrointestinal side effects such as nausea and vomiting may occur Amphotericin B is an antifungal drug that can produce fungicidal or fungistatic effects depending on the concentration of the dose relative to the susceptibility of the fungal target.

Unlike fluconazole and ketoconazole which targets the production ergosterol, amphotericin B specifically targets the ergosterol itself by to it, thus destabilising the integrity of the cell membrane which leads to the formation of transmembrane channels which in itself causes the contents of the fungus to leak out, resulting in cell death.

Amphotericin B is used in the treatment of leishmania through intravenous injection of 0. Sodium stibogluconate is an anti- leishmania drug that can be applied through the intravenous and intralesional pathways. The mechanism of action follows the inhibition of DNA topoisomerase which is vital for DNA replication and transcription.

This is because DNA topoisomerase controls the release and recombination of the DNA strand, which if inhibited prevents the cell from replicating leading to cell death. Paromomycin is an antibiotic that inhibits bacterial protein synthesis.

The mechanism of action follows the binding of paromomycin to the 16 s ribosomal RNA which then results in the formation of defective polypeptide chains during the protein synthesis. This eventually leads to the build of defective proteins within the bacterial system, thus resulting in bacterial death.

Doxycycline is a synthetically derived antibiotic used in the treatment of a wide range of bacterial infections. The mechanism of action follows the binding of doxycycline onto the 16 s rRNA area of the bacterial ribosome which is responsible for protein synthesis.

Once bound, the 16srRNA portion is unable to bind to RNA s which ultimately prevents protein translation from occurring. Overtime this prevents the bacteria from replicating, thereby producing a bacteriostatic effect.

Amoxicillin is an antibiotic derived from penicillin for the treatment of gram-positive bacteria. Amoxicillin works by inhibiting the continual cross-linkage of the bacterial cell wall through the disruption of penicillin binding proteins.

Overtime the bacterial cell wall weakens due to the imbalance between enzyme based autolytic action and cross-link maintenance, ultimately leading to the leakage of the bacterial organelles and thus cell death. Cefuroxime is a beta-lactam antibiotic that covers a broad spectrum of bacterial infections, similar to that of penicillin.

The antibacterial mechanism of cefuroxime follows the inhibition of the bacterial wall synthesis process, specifically that of the third and the final stage. This disrupts the formation of peptidoglycan layer that makes up the bacterial cell wall which leads to bacterial cell death through the leakage of its internal content.

Mebendazole is an anthelmintic used to treat the infection from parasitic worms such as myiasis The mechanism of action works by directly preventing the parasitic worms from producing microtubules which are needed to facilitate the absorption of glucose when the worm is in its larval and adult stages.

Mebendazole binds to tubulin preventing it from undergoing polymerisation which in itself prevents the formation of microtubules. As a result of the parasite being unable to uptake glucose it eventually depletes it energy storage and dies as a result.

Levamisole is an anthelmintic drug designed to treat bacterial and viral infections from parasitic sources such as myiasis Levamisole specifically targets the nicotine receptors as a way of facilitating its mechanism of action against parasites.

The specific action that is facilitated by levamisole follows the severe reduction in copulative capacity, via the inhibition of the male parasite from using its reproductive muscles, thereby preventing copulation from occurring.

Other benefits also include the stimulation of host-cell activation, coupled with improved phagocytotic functions, however it has been withdrawn from the market due to a variety of adverse effects. Moxidectin is a semisynthetic antiparasitic drug that works against both endo and ectoparasites.

The mechanism of action works via the specific binding of the chloride ion channels within the parasite which are required for the normal functioning of nerve and muscle cells. After moxidectin had been bound to the parasite, the ion channels become more permeable resulting in a high increase of chloride ions within the parasite, leading to its paralysis and its eventual demise.

Moxidectin is generally prescribed in 8 mg doses with varying dosage periods depending on the severity of onchocerciasis, however it has been replaced by ivermectin in most cases Despite the efficacy of antibiotics, they can also produce significant side effects which occur as a result of their systemic distribution within the host.

This issue coupled with the development of antibiotic resistance result in a situation whereby antibiotics can no longer be considered as a sustainable anti-parasitic method, which further incentivises for the development of a localised anti-parasitic treatment that specifically targets the parasites instead of resulting in unwanted systemic effects.

Therefore, there is an urgent need to develop alternative cost-effective treatment methods for patients with cutaneous parasite infection. The typical approaches to this method include the utilisation of infrared light, hot baths and laser therapy, all of which can generate non-localized heat that can damage the other tissue surrounding the cutaneous lesion of interest Due to such reasons, radiofrequency-based thermotherapies were developed as a means of more accurately targeting leishmanial lesions without affecting surrounding tissue, thus leading to higher quality treatment with minimal side effects.

Generally speaking radio frequency based thermotherapy is the most effective, where some studies have shown that a single application was able to encourage the reepithelization of the leishmania affected lesion, thus improving the speed of healing It should also be noted that the utilisation of radio frequencies can also help to stimulate increased collagen synthesis, contraction and remodelling which ultimately results in improved cutaneous healing with significantly better cosmetic results Despite the various advantages presented by radio frequency induced thermotherapy, the main limitations follow the fact that radio frequencies only penetrate to a depth of 4 mm which is ideal for leishmania amastigotes, but not for other cases of leishmaniasis that have penetrated deeper into the subcutaneous tissue, thereby limiting its usage to only superficial leishmaniasis.

html are used as a thermal mechanism to kill parasites in fish have been reported. Cryotherapy is an alternative treatment for leishmaniasis , which typically either utilises liquid carbon dioxide or liquid nitrogen to kill the parasites.

This has shown to be quite effective in regard to the facilitation of amastigote based cryonecrosis. This low clinical success rate may be attributed to a variety of different factors, such as the fact that this cryotherapy does not immediately contact the dermis due to the Leidenfrost effect, which in turn reduces the efficacy of the therapy, as immediate contact is required to eliminate the parasites without damaging the surrounding cutaneous tissue Other factors include the duration and frequency of each cryotherapy session, as the duration of each liquid nitrogen application may be too short between each interval to effectively inhibit the proliferation of parasites within the affected lesions Similar effects are observed when cryo-treating patients with tunga penetrans Although efficacy is observed against leishmaniasis and tunga penetrans , cryotherapy is not recommended for other cutaneous parasites such as gnathostomiasis.

Photodynamic therapy in the context of cutaneous anti- leishmanial treatment refers to the utilization of photo-excitable dyes in conjunction with specific wavelength frequencies to induce the release of reactive oxygen species ROS , which in turns results in the photodynamic inactivation of the parasites.

In the case of Leishmania , the dyes uroporphyrin and phthalocyanines are utilised to facilitate complete deactivation Other dyes include methylene blue which can serve as a low-cost alternative for photodynamic therapy The main advantage of this therapy is that the dye can selectively accumulate within the parasite prior to the application of the ROS inducing wavelengths.

This allows for the effective destruction of parasites without harming the host tissue. The application of lasers for anti-parasitic treatment is dependent on the type of laser that is used, which determines its output, oscillation form and conversion efficiency.

Output refers to the strength of the laser in megawatts, whilst oscillation form refers to the motion of the laser which can either be pulsed of continuous. Conversion efficiency refers to balance in the energy input with respect to useful energy output.

Lasers are classed into 3 different types, gas lasers, solid-state laser and semiconductor lasers, however only gas and solid-state lasers are used for antiparasitic treatments.

Gas lasers utilise gas as its laser medium, which in the specific context of anti-leishmanial treatment, either requires the use of carbon dioxide or argon. Solid-state lasers use ores as the laser medium, which in the context of anti-leishmanial treatment uses neodymium-doped yttrium aluminium garnet Nd:YAG or erbium The general consensus is that carbon dioxide is the most commonly utilised compound for leishmanial laser therapy, which is primarily due to its abundance in nature, coupled with its effectiveness and safety when used for leishmania.

The only problems associated with carbon dioxide lasers, are the minor side effects which are generally of a cosmetic nature, such as hypertrophic scarring, erythema and hyperpigmentation The other compounds also elicit similar results to carbon dioxide, but with differing levels of efficacy.

An advantage of using laser therapy lies in the fact that the power density can be varied to induce various effects upon the affected lesion i. Another form of laser therapy is the use of pulsed dye laser which improves the cutaneous properties of the lesion, resulting in improved pliability, reduced lesion size, reduction in erythema and improved skin texture, however one of the problems of pulsed laser dyes lies in its limited penetration depth, which constrains it to only superficial applications The limitations associated with laser penetration depth is primarily dependent on the laser medium and the wavelength that is used, as opposed to the oscillation form.

An example would be Nd:YAG at differing wavelengths, where by nm only results in partial penetration through the stratum corneum, whilst at nm results in the laser penetrating through to the dermal vasculature layer There is large scope within nanotechnology to help in the development of new platforms.

These may be either based on drug carriers such as liposomes, polymeric micelles or dendrimers, incorporated into larger macromolecular structures such as into hydrogels, wafers or even into bandages. The standard delivery method of anti-parasitic compounds typically follows the ingestion route which leads to the systemic circulation of the compound, resulting in lower efficacy, non-specificity and increased side effects.

To combat this issue, nanoparticles have been utilised as a means of increasing the efficacy of drug delivery whilst reducing the levels toxicity. In the case of leishmaniasis treatments, it has been reported that a variety of different nanoparticles have shown significant effectiveness against the parasite.

For drug delivery, liposomal preparations of antimicrobials such as amphotericin B have been reported for leishmainia treatments 63 , 64 , whilst polymeric carriers have been reported loaded with primaquine 65 or amphotericin B Combined delivery of antibiotics using nanotechnology delivery systems has resulted in reduced resistance 67 , these findings can be used to guide the development of interventions of new anti-parasitics.

Whilst there is some progress in this field there is huge scope to improve and widen the target from leishmaniasis to other parasites. Aside from drug delivery, nanotechnology can be used topically as a local lethal dose killing off parasite activity.

Iron III oxide nanoparticles have displayed anti- leishmanial effects, in which the suggested mechanism of action occurs through the production of nitric oxide Nitric oxide is one of the main molecules utilised by macrophage against leishmania , which involves the macrophage undertaking the oxidative burst mechanism.

This produces high quantities of nitric oxide and ROS which effectively facilitates the elimination of promastigotes within the macrophage, thereby limiting the population size within the host Whilst the ROS induced mechanism of anti-parasitic activity is well understood, the same does not apply to nitric oxide as its specific mechanism is still not fully understood.

Current research indicates that nitric oxide is not directly involved in the direct killing of leishmaniasis and may instead contribute to host tissue damage 70 , however it has also been shown that downregulation of nitric oxide provides Leishmania with a form of immune escape via reduced host response 71 , thereby suggesting that nitric acid is needed to prevent immune escape, thus implying that nitric acid is needed to initiate a host response against the parasite.

Another exciting application of nanotechnology for treatment of cutaneous leishmaniasis is the use of iron oxide coupled with magnetic flux, this results in magnetic hyperthermia which can be used to kill parasites.

Berry et al. reported the use of iron oxide as heat seeds for thermal kill of amastigote cells in vitro This study in combination with the ROS generation finding, indicates that iron oxide nanoparticles may be a frontrunner in the next generation of leishmania treatments.

The literature in this area is highly biased towards leishmania treatment, however, there is scope to develop therapeutics for other cutaneous parasites. The beauty of nanotechnology lies within the breadth of unique qualities each material possesses at the nano-scale domain, as well as the ease of tailor-ability towards bespoke applications.

We believe that more work targeted in this area towards some of the less studied parasites may render great reward.

The current treatments for cutaneous parasites are virtually all encompassed by the use of drugs as a general solution. Alternative treatments are effective, but nonetheless are limited to a specific type of parasite. The primary issue that is inhibiting the development of a general purpose non-antibiotic based therapy lies in the fact that all cutaneous parasites have different life cycle mechanisms, coupled with varying migratory routes which may not result in the parasites having an extended period of time whereby they dwell within the superficial layers of skin.

For a parasite such as leishmaniasis , which dwells within the superficial layer of skin, non-invasive treatments can be applied to a high level of efficacy as the parasite lives within the cutaneous nodules, thereby acting as a viable point for exploitation.

Other parasites have shown to pass through the upper cutaneous region during their migratory routes, however unlike leishmaniasis and possibly onchocerciasis, other parasites are not known to live within exposed regions of the host and as of such cannot be treated through alternative treatments.

Perhaps a consideration that needs to be taken is our current methods for approaching parasitic treatment. Our current alternative methods aim to target the parasites based on where they reside, which presents us with a specific set of limitations, specifically the depth and invasiveness of the treatment that can be applied.

Instead, it may be worth considering developing a method which instead influences the migratory route of the parasite, thereby herding them to a specific area where they can then be annihilated in a more efficient manner.

Whilst this method itself may not specifically partake in the direct destruction of the parasite; it will instead act as a process to facilitate the controlled movement of parasites, which will hamper their development as a bare minimum.

The primary concern regarding this method would be the use of an effective antiparasitic agent that does not compromise the safety of the host. This compound would be required to fulfil two specific requirements, one of which is for it to be non-cytotoxic to human cells and the second is for the compound itself to be able to be systemically circulated around the host before it is safely excreted out.

The compound itself should also be able to exude a repulsive effect towards the parasite, which would therefore allow the migratory route to be influenced. Assuming that the compounds will temporarily accumulate in certain regions of the host, it will therefore act as a temporary road-block within the parasites migratory route, forcing them to undertaken a different migratory path.

The main issue of this method is that there are currently no clinically known compounds that would have such effects and would also require a significant amount of time and resources to identify the changes in migratory pattern.

Despite the significant problems associated with this method, it may be feasible with the use of magnetic nanoparticles, whereby their distribution within the host can be controlled through the use of an attunable magnetic field. Ultimately, there is an urgent need for new pragmatic treatment approaches to parasitic infection.

Often such cases present in tropical climates or low-income countries, both of which may result in challenges for administration. Biomaterials research and expertise has vastly grown over the past two decades, with solution based approaches to multiple clinical conditions or disease states.

These platform technologies could be adapted to suit the requirements for the treatment of cutaneous parasite infections, however, greater awareness of the clinical need is required in order to leverage greater research investment for such progress to be realised.

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There are six major parasitic strategies , namely parasitic castration ; directly transmitted parasitism; trophically -transmitted parasitism; vector -transmitted parasitism; parasitoidism ; and micropredation.

These apply to parasites whose hosts are plants as well as animals. A perspective on the evolutionary options can be gained by considering four key questions: the effect on the fitness of a parasite's hosts; the number of hosts they have per life stage; whether the host is prevented from reproducing; and whether the effect depends on intensity number of parasites per host.

From this analysis, the major evolutionary strategies of parasitism emerge, alongside predation. Parasitic castrators partly or completely destroy their host's ability to reproduce, diverting the energy that would have gone into reproduction into host and parasite growth, sometimes causing gigantism in the host.

The host's other systems remain intact, allowing it to survive and to sustain the parasite. In the case of Sacculina , the testes of over two-thirds of their crab hosts degenerate sufficiently for these male crabs to develop female secondary sex characteristics such as broader abdomens, smaller claws and egg-grasping appendages.

Various species of helminth castrate their hosts such as insects and snails. This may happen directly, whether mechanically by feeding on their gonads, or by secreting a chemical that destroys reproductive cells; or indirectly, whether by secreting a hormone or by diverting nutrients.

For example, the trematode Zoogonus lasius , whose sporocysts lack mouths, castrates the intertidal marine snail Tritia obsoleta chemically, developing in its gonad and killing its reproductive cells. Directly transmitted parasites, not requiring a vector to reach their hosts, include such parasites of terrestrial vertebrates as lice and mites; marine parasites such as copepods and cyamid amphipods; monogeneans ; and many species of nematodes, fungi, protozoans, bacteria, and viruses.

Whether endoparasites or ectoparasites, each has a single host-species. Within that species, most individuals are free or almost free of parasites, while a minority carry a large number of parasites; this is known as an aggregated distribution. Trophically -transmitted parasites are transmitted by being eaten by a host.

They include trematodes all except schistosomes , cestodes , acanthocephalans , pentastomids , many roundworms , and many protozoa such as Toxoplasma. In their juvenile stages they infect and often encyst in the intermediate host. When the intermediate-host animal is eaten by a predator, the definitive host, the parasite survives the digestion process and matures into an adult; some live as intestinal parasites.

Many trophically transmitted parasites modify the behaviour of their intermediate hosts, increasing their chances of being eaten by a predator.

As with directly transmitted parasites, the distribution of trophically transmitted parasites among host individuals is aggregated. Vector-transmitted parasites rely on a third party, an intermediate host, where the parasite does not reproduce sexually, [14] to carry them from one definitive host to another.

Parasitoids are insects which sooner or later kill their hosts, placing their relationship close to predation. They can be divided into two groups, idiobionts and koinobionts, differing in their treatment of their hosts.

Idiobiont parasitoids sting their often-large prey on capture, either killing them outright or paralysing them immediately. The immobilised prey is then carried to a nest, sometimes alongside other prey if it is not large enough to support a parasitoid throughout its development.

An egg is laid on top of the prey and the nest is then sealed. The parasitoid develops rapidly through its larval and pupal stages, feeding on the provisions left for it.

Koinobiont parasitoids, which include flies as well as wasps, lay their eggs inside young hosts, usually larvae. These are allowed to go on growing, so the host and parasitoid develop together for an extended period, ending when the parasitoids emerge as adults, leaving the prey dead, eaten from inside.

Some koinobionts regulate their host's development, for example preventing it from pupating or making it moult whenever the parasitoid is ready to moult. They may do this by producing hormones that mimic the host's moulting hormones ecdysteroids , or by regulating the host's endocrine system.

A micropredator attacks more than one host, reducing each host's fitness by at least a small amount, and is only in contact with any one host intermittently.

This behavior makes micropredators suitable as vectors, as they can pass smaller parasites from one host to another. They include annelids such as leeches , crustaceans such as branchiurans and gnathiid isopods, various dipterans such as mosquitoes and tsetse flies , other arthropods such as fleas and ticks, vertebrates such as lampreys , and mammals such as vampire bats.

Parasites use a variety of methods to infect animal hosts, including physical contact, the fecal—oral route , free-living infectious stages, and vectors, suiting their differing hosts, life cycles, and ecological contexts.

Among the many variations on parasitic strategies are hyperparasitism, [37] social parasitism, [38] brood parasitism, [39] kleptoparasitism, [40] sexual parasitism, [41] and adelphoparasitism.

Hyperparasites feed on another parasite, as exemplified by protozoa living in helminth parasites, [37] or facultative or obligate parasitoids whose hosts are either conventional parasites or parasitoids.

In oak gall systems, there can be up to five levels of parasitism. Hyperparasites can control their hosts' populations, and are used for this purpose in agriculture and to some extent in medicine.

The controlling effects can be seen in the way that the CHV1 virus helps to control the damage that chestnut blight , Cryphonectria parasitica , does to American chestnut trees, and in the way that bacteriophages can limit bacterial infections. It is likely, though little researched, that most pathogenic microparasites have hyperparasites which may prove widely useful in both agriculture and medicine.

Social parasites take advantage of interspecific interactions between members of eusocial animals such as ants , termites , and bumblebees. Examples include the large blue butterfly, Phengaris arion , its larvae employing ant mimicry to parasitise certain ants, [38] Bombus bohemicus , a bumblebee which invades the hives of other bees and takes over reproduction while their young are raised by host workers, and Melipona scutellaris , a eusocial bee whose virgin queens escape killer workers and invade another colony without a queen.

Intraspecific social parasitism occurs in parasitic nursing, where some individual young take milk from unrelated females. In wedge-capped capuchins , higher ranking females sometimes take milk from low ranking females without any reciprocation.

In brood parasitism , the hosts act as parents as they raise the young as their own. Brood parasites include birds in different families such as cowbirds , whydahs , cuckoos , and black-headed ducks.

These do not build nests of their own, but leave their eggs in nests of other species. The eggs of some brood parasites mimic those of their hosts, while some cowbird eggs have tough shells, making them hard for the hosts to kill by piercing, both mechanisms implying selection by the hosts against parasitic eggs.

In kleptoparasitism from Greek κλέπτης kleptēs , "thief" , parasites steal food gathered by the host. The parasitism is often on close relatives, whether within the same species or between species in the same genus or family.

For instance, the many lineages of cuckoo bees lay their eggs in the nest cells of other bees in the same family. A unique approach is seen in some species of anglerfish , such as Ceratias holboelli , where the males are reduced to tiny sexual parasites , wholly dependent on females of their own species for survival, permanently attached below the female's body, and unable to fend for themselves.

The female nourishes the male and protects him from predators, while the male gives nothing back except the sperm that the female needs to produce the next generation. Adelphoparasitism, from Greek ἀδελφός adelphós , brother [56] , also known as sibling-parasitism, occurs where the host species is closely related to the parasite, often in the same family or genus.

Parasitism has an extremely wide taxonomic range, including animals, plants, fungi, protozoans, bacteria, and viruses. Parasitism is widespread in the animal kingdom, [63] and has evolved independently from free-living forms hundreds of times.

By far the largest group is the parasitoid wasps in the Hymenoptera. Numbers are conservative minimum estimates. The columns for Endo- and Ecto-parasitism refer to the definitive host, as documented in the Vertebrate and Invertebrate columns. A hemiparasite or partial parasite such as mistletoe derives some of its nutrients from another living plant, whereas a holoparasite such as dodder derives all of its nutrients from another plant.

This provides them with the ability to extract water and nutrients from the host. A parasitic plant is classified depending on where it latches onto the host, either the stem or the root, and the amount of nutrients it requires.

Since holoparasites have no chlorophyll and therefore cannot make food for themselves by photosynthesis , they are always obligate parasites, deriving all their food from their hosts. About 4, species of parasitic plant in approximately 20 families of flowering plants are known.

Species within the Orobanchaceae broomrapes are among the most economically destructive of all plants. Species of Striga witchweeds are estimated to cost billions of dollars a year in crop yield loss, infesting over 50 million hectares of cultivated land within Sub-Saharan Africa alone.

Striga infects both grasses and grains, including corn , rice , and sorghum , which are among the world's most important food crops. Orobanche also threatens a wide range of other important crops, including peas , chickpeas , tomatoes , carrots , and varieties of cabbage.

Yield loss from Orobanche can be total; despite extensive research, no method of control has been entirely successful. Many plants and fungi exchange carbon and nutrients in mutualistic mycorrhizal relationships. Some species of myco-heterotrophic plants, mostly in the tropics, however effectively cheat by taking carbon from a fungus rather than exchanging it for minerals.

They have much reduced roots, as they do not need to absorb water from the soil; their stems are slender with few vascular bundles , and their leaves are reduced to small scales, as they do not photosynthesize.

Their seeds are very small and numerous, so they appear to rely on being infected by a suitable fungus soon after germinating. Parasitic fungi derive some or all of their nutritional requirements from plants, other fungi, or animals. Plant pathogenic fungi are classified into three categories depending on their mode of nutrition: biotrophs, hemibiotrophs and necrotrophs.

Biotrophic fungi derive nutrients from living plant cells, and during the course of infection they colonise their plant host in such a way as to keep it alive for a maximally long time. Necrotrophic pathogens on the other hand, kill host cells and feed saprophytically , an example being the root-colonising honey fungi in the genus Armillaria.

Pathogenic fungi are well-known causative agents of diseases on animals as well as humans. Fungal infections mycosis are estimated to kill 1. Protozoa such as Plasmodium , Trypanosoma , and Entamoeba [76] are endoparasitic.

They cause serious diseases in vertebrates including humans—in these examples, malaria, sleeping sickness, and amoebic dysentery —and have complex life cycles.

Many bacteria are parasitic, though they are more generally thought of as pathogens causing disease. To give a few examples, Bacillus anthracis , the cause of anthrax , is spread by contact with infected domestic animals ; its spores , which can survive for years outside the body, can enter a host through an abrasion or may be inhaled.

Borrelia , the cause of Lyme disease and relapsing fever , is transmitted by vectors, ticks of the genus Ixodes , from the diseases' reservoirs in animals such as deer. Campylobacter jejuni , a cause of gastroenteritis , is spread by the fecal—oral route from animals, or by eating insufficiently cooked poultry , or by contaminated water.

Haemophilus influenzae , an agent of bacterial meningitis and respiratory tract infections such as influenza and bronchitis , is transmitted by droplet contact. Treponema pallidum , the cause of syphilis , is spread by sexual activity. Viruses are obligate intracellular parasites, characterised by extremely limited biological function, to the point where, while they are evidently able to infect all other organisms from bacteria and archaea to animals, plants and fungi, it is unclear whether they can themselves be described as living.

They can be either RNA or DNA viruses consisting of a single or double strand of genetic material RNA or DNA , respectively , covered in a protein coat and sometimes a lipid envelope. They thus lack all the usual machinery of the cell such as enzymes , relying entirely on the host cell's ability to replicate DNA and synthesise proteins.

Most viruses are bacteriophages , infecting bacteria. Parasitism is a major aspect of evolutionary ecology; for example, almost all free-living animals are host to at least one species of parasite.

Vertebrates, the best-studied group, are hosts to between 75, and , species of helminths and an uncounted number of parasitic microorganisms. On average, a mammal species hosts four species of nematode, two of trematodes, and two of cestodes.

Perhaps 40 per cent of described species are parasitic. Parasitism is hard to demonstrate from the fossil record , but holes in the mandibles of several specimens of Tyrannosaurus may have been caused by Trichomonas -like parasites. This rare find in Thailand reveals more about the ecology of prehistoric parasites.

As hosts and parasites evolve together, their relationships often change. When a parasite is in a sole relationship with a host, selection drives the relationship to become more benign, even mutualistic, as the parasite can reproduce for longer if its host lives longer.

There are thus varied possibilities in host—parasite coevolution. Evolutionary epidemiology analyses how parasites spread and evolve, whereas Darwinian medicine applies similar evolutionary thinking to non-parasitic diseases like cancer and autoimmune conditions.

Long-term coevolution sometimes leads to a relatively stable relationship tending to commensalism or mutualism , as, all else being equal, it is in the evolutionary interest of the parasite that its host thrives. A parasite may evolve to become less harmful for its host or a host may evolve to cope with the unavoidable presence of a parasite—to the point that the parasite's absence causes the host harm.

For example, although animals parasitised by worms are often clearly harmed, such infections may also reduce the prevalence and effects of autoimmune disorders in animal hosts, including humans. Lynn Margulis and others have argued, following Peter Kropotkin 's Mutual Aid: A Factor of Evolution , that natural selection drives relationships from parasitism to mutualism when resources are limited.

This process may have been involved in the symbiogenesis which formed the eukaryotes from an intracellular relationship between archaea and bacteria, though the sequence of events remains largely undefined.

Competition between parasites can be expected to favour faster reproducing and therefore more virulent parasites, by natural selection. Among competing parasitic insect-killing bacteria of the genera Photorhabdus and Xenorhabdus , virulence depended on the relative potency of the antimicrobial toxins bacteriocins produced by the two strains involved.

When only one bacterium could kill the other, the other strain was excluded by the competition. But when caterpillars were infected with bacteria both of which had toxins able to kill the other strain, neither strain was excluded, and their virulence was less than when the insect was infected by a single strain.

A parasite sometimes undergoes cospeciation with its host, resulting in the pattern described in Fahrenholz's rule , that the phylogenies of the host and parasite come to mirror each other. An example is between the simian foamy virus SFV and its primate hosts.

The phylogenies of SFV polymerase and the mitochondrial cytochrome c oxidase subunit II from African and Asian primates were found to be closely congruent in branching order and divergence times, implying that the simian foamy viruses cospeciated with Old World primates for at least 30 million years.

The presumption of a shared evolutionary history between parasites and hosts can help elucidate how host taxa are related. For instance, there has been a dispute about whether flamingos are more closely related to storks or ducks.

The fact that flamingos share parasites with ducks and geese was initially taken as evidence that these groups were more closely related to each other than either is to storks. However, evolutionary events such as the duplication, or the extinction of parasite species without similar events on the host phylogeny often erode similarities between host and parasite phylogenies.

In the case of flamingos, they have similar lice to those of grebes. Flamingos and grebes do have a common ancestor, implying cospeciation of birds and lice in these groups. Flamingo lice then switched hosts to ducks, creating the situation which had confused biologists.

Parasites infect sympatric hosts those within their same geographical area more effectively, as has been shown with digenetic trematodes infecting lake snails. Parasites track the locally common hosts' phenotypes, so the parasites are less infective to allopatric hosts, those from different geographical regions.

Some parasites modify host behaviour in order to increase their transmission between hosts, often in relation to predator and prey parasite increased trophic transmission. For example, in the California coastal salt marsh , the fluke Euhaplorchis californiensis reduces the ability of its killifish host to avoid predators.

Another example is the protozoan Toxoplasma gondii , a parasite that matures in cats but can be carried by many other mammals. Uninfected rats avoid cat odors, but rats infected with T.

gondii are drawn to this scent, which may increase transmission to feline hosts. Instead of producing their normal sticky spiral shaped webs, they made simplified webs when the parasites were attached. This manipulated behavior lasted longer and was more prominent the longer the parasites were left on the spiders.

Parasites can exploit their hosts to carry out a number of functions that they would otherwise have to carry out for themselves. Parasites which lose those functions then have a selective advantage, as they can divert resources to reproduction.

Many insect ectoparasites including bedbugs , batbugs , lice and fleas have lost their ability to fly , relying instead on their hosts for transport. Hosts have evolved a variety of defensive measures against their parasites, including physical barriers like the skin of vertebrates, [] the immune system of mammals, [] insects actively removing parasites, [] and defensive chemicals in plants.

The evolutionary biologist W. Hamilton suggested that sexual reproduction could have evolved to help to defeat multiple parasites by enabling genetic recombination , the shuffling of genes to create varied combinations. Hamilton showed by mathematical modelling that sexual reproduction would be evolutionarily stable in different situations, and that the theory's predictions matched the actual ecology of sexual reproduction.

This is because the male hormone testosterone encourages the growth of secondary sex characteristics, favouring such males in sexual selection , at the price of reducing their immune defences. The physical barrier of the tough and often dry and waterproof skin of reptiles, birds and mammals keeps invading microorganisms from entering the body.

Human skin also secretes sebum , which is toxic to most microorganisms. Vertebrate saliva and tears contain lysozyme , an enzyme that breaks down the cell walls of invading bacteria. Once inside the body, parasites must overcome the immune system 's serum proteins and pattern recognition receptors , intracellular and cellular, that trigger the adaptive immune system's lymphocytes such as T cells and antibody-producing B cells.

These have receptors that recognise parasites. Insects often adapt their nests to reduce parasitism. For example, one of the key reasons why the wasp Polistes canadensis nests across multiple combs , rather than building a single comb like much of the rest of its genus, is to avoid infestation by tineid moths.

The tineid moth lays its eggs within the wasps' nests and then these eggs hatch into larvae that can burrow from cell to cell and prey on wasp pupae. Adult wasps attempt to remove and kill moth eggs and larvae by chewing down the edges of cells, coating the cells with an oral secretion that gives the nest a dark brownish appearance.

Plants respond to parasite attack with a series of chemical defences, such as polyphenol oxidase , under the control of the jasmonic acid-insensitive JA and salicylic acid SA signalling pathways. In general, plants can either initiate a specific or a non-specific response.

These are effective against a wide range of parasites. Parasitism and parasite evolution were until the twenty-first century studied by parasitologists , in a science dominated by medicine, rather than by ecologists or evolutionary biologists. Even though parasite-host interactions were plainly ecological and important in evolution, the history of parasitology caused what the evolutionary ecologist Robert Poulin called a "takeover of parasitism by parasitologists", leading ecologists to ignore the area.

This was in his opinion "unfortunate", as parasites are "omnipresent agents of natural selection" and significant forces in evolution and ecology. The technical languages of ecology and parasitology sometimes involved different meanings for the same words.

There were philosophical differences, too: Poulin notes that, influenced by medicine, "many parasitologists accepted that evolution led to a decrease in parasite virulence, whereas modern evolutionary theory would have predicted a greater range of outcomes".

Their complex relationships make parasites difficult to place in food webs: a trematode with multiple hosts for its various life cycle stages would occupy many positions in a food web simultaneously, and would set up loops of energy flow, confusing the analysis.

Further, since nearly every animal has multiple parasites, parasites would occupy the top levels of every food web. Parasites can play a role in the proliferation of non-native species. For example, invasive green crabs are minimally affected by native trematodes on the Eastern Atlantic coast. This helps them outcompete native crabs such as the Atlantic Rock and Jonah crabs.

Ecological parasitology can be important to attempts at control, like during the campaign for eradicating the Guinea worm. Even though the parasite was eradicated in all but four countries, the worm began using frogs as an intermediary host before infecting dogs, making control more difficult than it would have been if the relationships had been better understood.

Although parasites are widely considered to be harmful, the eradication of all parasites would not be beneficial. Parasites account for at least half of life's diversity; they perform important ecological roles; and without parasites, organisms might tend to asexual reproduction, diminishing the diversity of traits brought about by sexual reproduction.

The presence of parasites thus indicates that an ecosystem is healthy. An ectoparasite, the California condor louse, Colpocephalum californici , became a well-known conservation issue.

A major and very costly captive breeding program was run in the United States to rescue the California condor. It was host to a louse, which lived only on it. Any lice found were "deliberately killed" during the program, to keep the condors in the best possible health.

The result was that one species, the condor, was saved and returned to the wild, while another species, the parasite, became extinct. Although parasites are often omitted in depictions of food webs , they usually occupy the top position.

Parasites can function like keystone species , reducing the dominance of superior competitors and allowing competing species to co-exist. A single parasite species usually has an aggregated distribution across host animals, which means that most hosts carry few parasites, while a few hosts carry the vast majority of parasite individuals.

This poses considerable problems for students of parasite ecology, as it renders parametric statistics as commonly used by biologists invalid.

Log-transformation of data before the application of parametric test, or the use of non-parametric statistics is recommended by several authors, but this can give rise to further problems, so quantitative parasitology is based on more advanced biostatistical methods.

Human parasites including roundworms, the Guinea worm , threadworms and tapeworms are mentioned in Egyptian papyrus records from BC onwards; the Ebers Papyrus describes hookworm.

In ancient Greece , parasites including the bladder worm are described in the Hippocratic Corpus , while the comic playwright Aristophanes called tapeworms "hailstones". The Roman physicians Celsus and Galen documented the roundworms Ascaris lumbricoides and Enterobius vermicularis.

In his Canon of Medicine , completed in , the Persian physician Avicenna recorded human and animal parasites including roundworms, threadworms, the Guinea worm and tapeworms.

In his book Traité de l'état, science et pratique de l'art de la Bergerie Account of the state, science and practice of the art of shepherding , Jehan de Brie [ fr ] wrote the first description of a trematode endoparasite, the sheep liver fluke Fasciola hepatica.

In the early modern period , Francesco Redi 's book Esperienze Intorno alla Generazione degl'Insetti Experiences of the Generation of Insects , explicitly described ecto- and endoparasites, illustrating ticks , the larvae of nasal flies of deer , and sheep liver fluke.

In , Antonie van Leeuwenhoek observed and illustrated the protozoan parasite Giardia lamblia , and linked it to "his own loose stools".


Week 5 Parasite survival strategies Anti-parasite strategies

Author: Moogull

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