Anti-parasite strategies -
Also discussed is the possibility that host behavioural patterns that may defend against one parasite may be exploited by a different type of parasite to facilitate its own transmission.
The interplay between host defensive strategies, the cost versus the effectiveness of such strategies, and a parasite's evasion or exploitation of such strategies, may be useful in understanding some aspects of host-parasite dynamics in nature. Abstract Behavioural patterns involved in avoiding, repelling, or removing parasites allow mammalian hosts to defend themselves from an array of parasites that threaten the host's fitness in the natural world.
Why Are Life Histories So Variable? Comparative Genomics. Case Study: The Glorious, Golden, and Gigantic Quaking Aspen.
Cybertaxonomy and Ecology. Molecular Genetic Techniques and Markers for Ecological Research. Ecological Opportunity: Trigger of Adaptive Radiation.
Evidence for Meat-Eating by Early Humans. Resource Partitioning and Why It Matters. The Evolution of Aging. Hauber Dept. of Psychology at Hunter College, CUNY © Nature Education. Citation: Croston, R. Nature Education Knowledge 3 10 Brood parasitic birds lay their eggs in the nests of others, sparing themselves the expense of rearing their own young.
The resulting coevolutionary arms race includes sophisticated defenses by hosts and escalating tools of exploitation by parasites. Aa Aa Aa. Brood Parasitism as a Reproductive Strategy. Evolution and Maintenance.
The Coevolutionary "Arms-Race". Egg Mimicry. Nestling Mimicry. Identity Crisis? Conservation Impacts of Brood Parasitism. As a widespread generalist brood parasite, the native Brown-headed Cowbird poses a conservation threat to several of its North American passerine hosts.
For brown-headed cowbird host populations already in decline, such as the endangered Kirtland's Warblers Dendroica kirtlandii , Black-capped Vireos Vireo atricapilla , Least Bell's Vireos Vireo bellii pusillus , and Southwestern Willow Flycatchers Empidonax traillii extimus , the effects of this can be devastating, and human control of cowbird population size may be necessary to prevent local extinctions Smith et al.
This is a particular consideration for conservation biologists working with hosts of generalist brood parasites, because even when a species declines in number it may continue to be parasitized at high rates, since as generalist parasites, the cowbird population will not be impacted reciprocally with that of individual host species.
These applied aspects of host-parasite interactions confirm that scientifically informed conservation management is critical for the efficient and productive planning and implementation of long term goals Hauber ; Parker et al.
References and Recommended Reading Anderson, M. Davies, N. Cuckoos, Cowbirds and other Cheats. London, UK: T. Poyser, Ecology and Management of Cowbirds and Their Hosts.
Austin: University of Texas Press, Article History Close. Share Cancel. Revoke Cancel. Keywords Keywords for this Article. Save Cancel. Flag Inappropriate The Content is: Objectionable. Flag Content Cancel. share Close. Email your Friend. Submit Cancel.
This content is currently under construction. Explore This Subject. Topic rooms within Evolution Close. No topic rooms are there.
Lead Editor: Nick Bisceglia Evolution. Or Browse Visually. Other Topic Rooms Ecology. Student Voices. Creature Cast. Simply Science. Green Screen. Green Science. Bio 2. The Success Code. Why Science Matters. The Beyond.
Plant ChemCast. Postcards from the Universe. Brain Metrics. Mind Read. Eyes on Environment. The first larval stage nematodes are then ingested by copepods which then allow the nematodes to reach their second larval stage. This second larval stage nematode is then ingested by larger species such as fish, i.
Humans then typically ingest the infected fish in its raw or undercooked state, which allows the third larval stage nematode to migrate from the second host into its human host via the penetration of the intestinal mucosa. This is most prevalent in certain regions of the world, where raw fish is consumed regularly as a part of the regions culture, i.
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.
Bravo F, Gontijo B. Gnathostomiasis: an emerging infectious disease relevant to all dermatologists. An Bras Dermatol. Article PubMed PubMed Central Google Scholar. Herman JS, Chiodini PL. Gnathostomiasis, Another Emerging Imported Disease.
Clin Microbiol Rev. McGwire BS, Satoskar AR. Leishmaniasis: clinical syndromes and treatment. Article CAS PubMed Google Scholar. Skar GL, Simonsen KA. Lyme Disease, StatPearls Publishing, Treasure Island, Florida, USA, Müllegger RR, Glatz M.
Skin Manifestations of Lyme Borreliosis. Am J Clin Dermatol. Article PubMed Google Scholar. McGraw TA, Turiansky GW. Cutaneous myiasis. J Am Acad Dermatol.
Robbins K, Khachemoune A. Cutaneous myiasis: a review of the common types of myiasis. Int J Dermatol. Njim T, Ngum JM, Aminde LN. Cutaneous onchocerciasis in Dumbu, a pastoral area in the North-West region of Cameroon: diagnostic challenge and socio-economic implications.
Pan Afr Med J. Okulicz JF, Stibich AS, Elston DM, Schwartz RA. Cutaneous onchocercoma. Madke B, Khopkar U. Pediculosis capitis: An update. Article Google Scholar. Ko CJ, Elston DM. Banerji A.
Anti-parasite strategies either tolerate avian brood parasitism or reject Menstrual health initiatives by ejecting parasitic Stdategies, as seen stratsgies Anti-parasite strategies Sports nutrition for bodybuilders hosts steategies common cuckoos, Cuculus canorus, Antj-parasite by abandoning parasitized clutches, as seen in most rejecter hosts of brown-headed cowbirds, Anti-parqsite Anti-parasite strategies. What explains consistent variation between strategiies Anti-parasite strategies behaviours of hosts Anti-parasite strategies stratgeies Anti-parasite strategies species and across species when exposed to different types of parasites? Life history theory predicts that when parasites decrease the fitness of host offspring, but not the future reproductive success of host adults, optimal clutch size should decrease. Consistent with this prediction, evolutionarily old cowbird hosts, but not cuckoo hosts, have lower clutch sizes than related rarely- or newly parasitized species. We constructed a mathematical model to calculate the fitness payoffs of egg ejector vs. nest abandoner hosts to determine if various aspects of host life history traits and brood parasites' virulence on adult and young host fitness differentially influence the payoffs of alternative host defences. These calculations showed that in general egg ejection was a superior anti-parasite strategy to nest abandonment. Brood parasitism is a subclass of parasitism Anti-paraste phenomenon and stratefies pattern of certain animals Anti-parasitd, brood Power-packed nutritionthat etrategies Anti-parasite strategies others to raise Anti-parasite strategies young. The Anti-pwrasite appears among birdsinsects and Anti-parasite strategies. The Anri-parasite Anti-parasite strategies manipulates Anti-parxsite Anti-parasite strategieseither of the same strategied of another species, to raise its young as if it were its own, usually using egg mimicrywith eggs that resemble the host's. The evolutionary strategy relieves the parasitic parents from the investment of rearing young. This benefit comes at the cost of provoking an evolutionary arms race between parasite and host as they coevolve : many hosts have developed strong defenses against brood parasitism, such as recognizing and ejecting parasitic eggs, or abandoning parasitized nests and starting over. It is less obvious why most hosts do care for parasite nestlings, given that for example cuckoo chicks differ markedly from host chicks in size and appearance.Anti-parasite strategies -
note, annotated bibliography IEEE Modern Languages Association 8th ed. MLA Vancouver. My Articles Add to my articles list Remove from my articles list. Article stats. URI Click to copy the URI to your clipboard. xml Copy to your clipboard. DOI Click to copy the URI to your clipboard.
Preservation Status Preservation Status Report a problem Report a problem. Keywords Anti-parasitic immunoprophylaxis vaccine types live vaccines recombinant vaccines synthetic peptide vaccines anti-idiotypic antibody vaccines antigen selection humoral immunity cell-mediated immunity adjuvants attenuated viral vectors attenuated bacterial vectors immunotherapy.
Arias de Reyna L, Coevolution of the great spotted cuckoo and its hosts. In: Parasitic birds and their hosts Rothstein SI, Robinson SK, eds. Oxford: Oxford University Press; Arias de Reyna L, Recuerda P, Corvillo M, Aguilar I, Reproducción del críalo Clamator glandarius en Sierra Morena Central.
Doñana Acta Vert 9 : Arcese P, Smith JNM, Hatch MI, Nest depredation by cowbirds and its consequences for passerine demography. Proc Natl Acad Sci USA 93 : Bazin RC, Sealy SG, Experiments on the responses of a rejecter species to threats of depredation and cowbird parasitism.
Ethology 94 : Birkhead TR, The magpies. The ecology and behavior of blackbilled and yellow-billed magpies. London: T and AD Poyser. Briskie JV, Sealy SG, Hobson KA, Behavioral defenses against avian brood parasitism in sympatric and allopatric host populations.
Evolution 46 : Davies NB, Brooke M de L, Cuckoos versus reed warblers: adaptations and counteradaptations. Anim Behav 36 : An experimental study of co-evolution between the cuckoo, Cuculus canorus and its hosts.
Host egg discrimination. J Anim Ecol 58 : Davies NB, Brooke M de L, Kacelnik A, Recognition errors and probability of parasitism determine whether reed warblers should accept or reject mimetic cuckoo eggs. Proc R Soc Lond B : Duckworth JW, Responses of breeding reed warblers Acrocephalus scirpaceus to mounts of sparrowhawk Accipiter nisus , cuckoo Cuculus canorus and jay Garrulus glandarius.
Ibis : 68 Fineblum WL, Rausher MD, Trade-off between resistance and tolerance to herbivore damage in a morning glory. Nature : Folkers KL, Lowther PE, Responses of nesting red-winged blackbirds and yellow warblers to brown headed cowbirds.
J Field Ornithol 56 : Friedmann H, The honey-guides. US Nat Mus Bull Gill SA, Grieff PM, Staib LM, Sealy SG, Does nest defense deter or facilitate cowbird parasitism? A test of the nesting cue hypothesis. Ethology : 56 Hochberg ME, Hide or fight?
The competitive evolution of concealment and encapsulation in parasitoid-host associations. Oikos 80 : Kelly C, A model to explore the rate of spread of mimicry and rejection in hypothetical populations of cuckoos and their hosts. J Theor Biol : Kraaijeveld AR, van Alphen JM, Foraging behavior and encapsulation ability of Drosophila melanogaster larvae: correlated polymorphisms?
Diptera: Drosophilidae. J Insect Behav 8 : MacLean IG, Rhodes G, Enemy recognition and response in birds. Curr Ornithol 8 : Marchetti K, Costs to host defense and the persistence of parasitic cuckoos. Proc R Soc Lond B : 41 Mauricio R, Rausher MD, Burdick DS, Variation in the defense strategies of plants: are resistance and tolerance mutually exclusive?
Ecology 78 : Moksnes A, Røskaft E, Adaptation of meadow pipits to parasitism by the common cuckoo. Behav Ecol Sociobiol 24 : 25 Moksnes A, Røskaft E, Braa AT, Korsnes L, Lampe HM, Pedersen HC, Behavioural responses of potential hosts towards artificial cuckoo eggs and dummies.
Behaviour : 64 Moksnes A, Røskaft E, Korsnes L, Rejection of cuckoo Cuculus canorus eggs by meadow pipits Anthus pratensis. Behav Ecol 4 : Neudorf DL, Sealy SG, Reactions of four passerine species to threats of depredation and cowbird parasitism: enemy recognition or generalized responses?
Behaviour : 84 Ortega CP, Cruz A, A comparative study of cowbird parasitism in yellow-headed blackbirds and red-winged blackbirds. Auk : 16 Payne RB, The ecology of brood parasitism in birds.
Annu Rev Ecol Syst 8 : 1 Clutch size, Laying periodicity and behavior in the honeyguides Indicator indicator and I. Proc VII Pan-Afr Orn Congr Nairobi : Avian brood parasitism.
In: Host parasite coevolution. General principles and avian models Clayton DH, Moore J, eds. Payne RB, Payne LL, Rowley I, Splendid wren Malurus splendens response to cuckoos: an experimental test of social organization in a communal bird.
Behaviour 94 : Redondo T, Carranza J, Offspring reproductive value and nest defense in the magpie. Behav Ecol Sociobiol 25 : Robertson RJ, Norman RF, Behavioral defenses to brood parasitism by potential hosts of the brown-headed cowbird.
Condor 78 : The function and evolution of aggressive host behavior towards the brown-headed cowbird Molothrus ater. Can J Zool 55 : Röell A, Bossema I, A comparison of nest defense by jackdaws, rooks, magpies and crows. Behav Ecol Sociobiol 11 : 1 Rohwer S, Spaw CD, Roskaft E, Cost to northern orioles of puncture-ejecting parasitic cowbird eggs from their nest.
Auk : Rothstein SI, An experimental and teleonomic investigation of avian brood parasitism. Condor 77 : A model system for coevolution: avian brood parasitism.
Annu Rev Ecol Syst 21 : Sealy SG, Removal of yellow warbler eggs in association with cowbird parasitism. Condor 94 : 40 Short LL, Horne JFM, Behavioral notes on the nest parasitic afrotropical honeyguides Aves: Indicatoridae.
Am Mus Nov : 1 Siegel S, Castellan NJ, Non-parametric statistics for the behavioral sciences , 2nd ed. New York: McGraw-Hill. Smith JNM, Arcese P, McLean IG, Age, experience, and enemy recognition by wild song sparrows. Behav Ecol Sociobiol 14 : Sokolowski MB, Pereira HS, Hughes K, Evolution of foraging behavior in Drosophila by density-dependent selection.
Proc Natl Acad Sci USA 94 : Soler JJ, Martínez JG, Soler M, Møller AP, Rejection behavior of European magpie populations in relation to genetic and geographic variation: an experimental test of rejecter-gene flow. Evolution 53 : Soler JJ, Sorci G, Soler M, Møller AP, Change in host rejection behavior mediated by the predatory behavior of its brood parasite.
Behav Ecol 10 : Soler M, Relationships between the great spotted cuckoo Clamator glandarius and its magpie host in a recently colonized area. Ornis Scand 21 : Soler M, Martínez JG, Soler JJ, Effects of brood parasitism by the great spotted cuckoo on the breeding success of the magpie host: an experimental study.
Ardeola 43 : 87 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". This was the first protozoan parasite of humans to be seen under a microscope.
Modern parasitology developed in the 19th century with accurate observations and experiments by many researchers and clinicians; [] the term was first used in James Paget discovered the intestinal nematode Trichinella spiralis in humans in James McConnell described the human liver fluke, Clonorchis sinensis , in Manson further predicted that the malaria parasite, Plasmodium , had a mosquito vector, and persuaded Ronald Ross to investigate.
Ross confirmed that the prediction was correct in — At the same time, Giovanni Battista Grassi and others described the malaria parasite's life cycle stages in Anopheles mosquitoes. 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.
About this region Anti-paraslte Form Enter Anti-parasite strategies terms. Strattegies query limiter Improve your athletic performance Article Title Keywords Anti-parasite strategies Author Journal Title Journal Title Exact ISSN DOI ORCID iD Load Date. Date limit:. Enter the date in the correct format. Relevance Most Recent Most Popular. Show only content I can access. Peer Reviewed.
0 thoughts on “Anti-parasite strategies”