Editing Myiasis

{{short description|Infestation of parasitic maggots}}
{{use dmy dates |date=December 2024 }}
{{Infobox medical condition (new)
| name          = Myiasis
| synonyms      = Flystrike, blowfly strike, fly-blown
| pronounce     = {{IPAc-en|m|aɪ|ˈ|aɪ|.|ə|s|ə|s}}
| image         = Miasis human.jpg
| caption       = Cutaneous myiasis in the shoulder of a human
| field         = [[Infectious disease (medical specialty)|Infectious disease]]
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'''Myiasis''' ({{IPAc-en|m|aɪ|.|ˈ|aɪ|.|ə|.|s|ə|s}} {{Respelling|my|EYE|ə|səss}}<ref>{{Cite web |title=Definition of MYIASIS |url=https://www.merriam-webster.com/dictionary/myiasis |access-date=2023-05-19 |website=merriam-webster.com |language=en}}</ref>), also known as '''flystrike''' or '''fly strike''', is the [[parasitic]] infestation of the body of a live animal by [[fly]] [[larva]]e ([[maggot]]s) that grow inside the host while feeding on its [[Biological tissue|tissue]]. Although flies are most commonly attracted to [[open wound]]s and [[urine]]- or [[feces]]-soaked fur, some species (including the most common myiatic flies—the [[botfly]], [[Calliphoridae|blowfly]], and [[Cochliomyia hominivorax|screwfly]]) can create an infestation even on unbroken skin. Non-myiatic flies (such as the common [[housefly]]) can be responsible for accidental myiasis.

Because some animals (particularly non-native domestic animals) cannot react as effectively as humans to the causes and effects of myiasis, [[Parasitic flies of domestic animals|such infestations]] present a severe and continuing problem for [[livestock]] industries worldwide, causing severe economic losses where they are not mitigated by human action.<ref>{{cite journal |last=Otranto |first=Domenico |date=2001 |title=The immunology of myiasis: parasite survival and host defense strategies |journal=Trends in Parasitology |volume=17 |issue=4 |pages=176–182 |doi=10.1016/S1471-4922(00)01943-7 |pmid=11282507}}</ref> Although typically a far greater issue for animals, myiasis is also a relatively frequent disease for humans in rural tropical regions where myiatic flies thrive, and often may require medical attention to surgically remove the parasites.<ref name="John 2006. p. 328-334">{{cite book |editor1-last=John |editor1-first=David |editor2-last=Petri |date=2006 |editor2-first=William |title=Markell and Voge's Medical Parasitology |edition=9th |location=Missouri |publisher=Saunders Elsevier |isbn=978-0-7216-4793-7 |pages=328–334}}</ref>

Myiasis varies widely in the forms it takes and its effects on those affected. Such variations depend largely on the fly species and where the larvae are located. Some flies lay eggs in open wounds, other larvae may invade unbroken skin or enter the body through the nose or ears, and still others may be swallowed if the eggs are deposited on the lips or food.<ref name="John 2006. p. 328-334"/> There can also be accidental myiasis that ''[[Eristalis tenax]]'' can cause in humans via water containing the larvae or in contaminated uncooked food. The name of the condition derives from [[ancient Greek]] μυῖα (''myia''), meaning "fly".<ref>{{LSJ|mui{{=}}a1|μυῖα|ref}}.</ref>
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== Signs and symptoms ==
How myiasis affects the human body depends on where the larvae are located. Larvae may infect dead, [[Necrosis|necrotic]] (prematurely dying) or living tissue in various sites: the skin, eyes, ears, stomach, and intestinal tract, or in genitourinary sites.<ref>{{cite journal |last1=Ockenhouse |first1=Christian F. |last2=Samlaska |first2=Curt P. |last3=Benson |first3=Paul M. |last4=Roberts |first4=Lyman W. |last5=Eliasson |first5=Arn |last6=Malane |first6=Susan |last7=Menich |first7=Mark D. |date=1990 |title=Cutaneous myiasis caused by the African tumbu fly (Cordylobia anthropophaga) |journal=Archives of Dermatology |volume=126 |issue=2 |pages=199–202 |doi=10.1001/archderm.1990.01670260069013 |pmid=2301958}}</ref> They may invade open wounds and lesions or unbroken skin. Some enter the body through the nose or ears. Larvae or eggs can reach the stomach or intestines if they are swallowed with food and cause gastric or intestinal myiasis.<ref name="John 2006. p. 328-334"/> In extremely rare cases, maggots may occasionally [[Vulvar myiasis|infest the vulvar area]].<ref>{{Cite journal |last1=Gupta |first1=Sanjeev |last2=Kataria |first2=Usha |last3=Siwach |first3=Sunita |date=2013 |title=Myiasis in female external genitalia |journal=Indian Journal of Sexually Transmitted Diseases and AIDS |language=en |volume=34 |issue=2 |pages=129–131 |doi=10.4103/0253-7184.120555 |pmid=24339466 |issn=0253-7184|pmc=3841665 |doi-access=free }}</ref>

Several different presentations of myiasis and their symptoms:<ref name="John 2006. p. 328-334"/>

{| class="wikitable"
|-
! Syndrome
! Symptoms
|-
| Cutaneous myiasis
| Painful, slow-developing ulcers or furuncle- (boil-) like sores that can last for a prolonged period
|-
| Nasal myiasis
| Obstruction of nasal passages and severe irritation. In some cases, facial edema and fever can develop. Death is not uncommon.
|-
| Aural myiasis
| Crawling sensations and buzzing noises. Smelly discharge is sometimes present. If located in the middle ear, larvae may get to the brain.
|-
| Ophthalmomyiasis
| Severe irritation, edema, and pain. Fairly common.
|}

===Wound===
[[File:Wounds myiasis new image.jpg|thumb|Wound myiasis in the scalp]]
Wound myiasis occurs when fly larvae infest open wounds. It has been a serious complication of war wounds in tropical areas and is sometimes seen in neglected wounds in most parts of the world. Predisposing factors include poor socioeconomic conditions, extremes of age, neglect, mental disability, psychiatric illness, alcoholism, diabetes, and [[Peripheral artery disease|vascular occlusive disease]].<ref>{{cite journal |vauthors=Namazi MR, Fallahzadeh MK |date=November 2009 |title=Wound myiasis in a patient with squamous cell carcinoma |journal=ScientificWorldJournal |volume=9 |pages=1192–3 |doi=10.1100/tsw.2009.138 |pmid=19882087|pmc=5823144 |doi-access=free }}</ref><ref>{{cite web |url=http://www.fao.org/ag/aga/agap/frg/feedback/war/u4220b/u4220b07.htm |title=Screwworm flies as agents of wound myiasis |publisher=Fao.org |access-date=2013-11-05}}</ref><ref>{{cite journal |last1=El-Azazy |first1=O.M.E. |date=1989 |title=Wound myiasis caused by Cochliomyia hominivorax in Libya |journal=Vet. Rec. |volume=124 |issue=4 |page=103 |doi=10.1136/vr.124.4.103-a|pmid=2929078 |s2cid=26982759 }}</ref><ref>{{cite journal |last1=Huntington |first1=T. E. |last2=Voigt |first2=David W. |last3=Higley |first3=L. G. |date=January 2008 |title=Not the Usual Suspects: Human Wound Myiasis by Phorids |journal=Journal of Medical Entomology |volume=45 |issue=1 |pages=157–159 |doi=10.1603/0022-2585(2008)45[157:NTUSHW]2.0.CO;2 |pmid=18283957|doi-access=free }}</ref><ref name="Clinic2010">{{cite book |author=Cleveland Clinic |title=Current Clinical Medicine: Expert Consult - Online |url=https://books.google.com/books?id=WHeY9woTzdoC&pg=PT1396 |access-date=22 April 2013 |date=13 August 2010 |publisher=Elsevier Health Sciences |isbn=978-1-4377-3571-0 |pages=1396–}}</ref>

===Eye===
Myiasis of the human [[eye]] or ophthalmomyiasis can be caused by ''[[Hypoderma tarandi]]'', a parasitic [[botfly]] of [[caribou]]. It is known to lead to [[uveitis]], [[glaucoma]], and [[retinal detachment]].<ref name=lag>{{cite journal |last1=Lagacé-Wiens |first1=P. R. |last2=Dookeran |first2=Ravi |last3=Skinner |first3=Stuart |last4=Leicht |first4=Richard |last5=Colwell |first5=Douglas D. |last6=Galloway |first6=Terry D. |display-authors=1 |date=January 2008 |title=Human ophthalmomyiasis interna caused by ''Hypoderma tarandi'', Northern Canada |journal=Emerging Infectious Diseases |volume=14 |issue=1 |pages=64–66 |doi=10.3201/eid1401.070163 |pmc=2600172 |pmid=18258079}}</ref>

==Cause==
===Life cycle===
The life cycle in sheep is typical of the disease. The female [[Fly|flies]] lay their eggs on the sheep in damp, protected areas of the body that are soaked with urine and feces, mainly the sheep's breech ([[buttocks]]). It takes approximately eight hours to a day for the eggs to hatch, depending on the conditions. Once hatched, the larvae then lacerate the skin with their mouthparts, causing open sores. Once the skin has been breached, the larvae then tunnel through the sores into the host's [[subcutaneous tissue]], causing deep and irritating [[lesion]]s highly subject to infection. After about the second day, [[bacteria]]l [[infection]] is likely and, if left untreated, causes [[bacteremia|bacterial bloodstream infections]] or [[sepsis]]. This leads to [[Anorexia (symptom)|anorexia]] and weakness and is generally fatal if untreated.<ref>{{cite journal|url=https://www.researchgate.net/publication/13484621|journal=Parassitologia|first=M.J.R.|last=Hall|title=Traumatic myiasis of sheep in Europe: a review|date=1997|volume=39|pages=409–413}}</ref>

===Species affecting humans===
There are three main [[Diptera|fly]] families causing economically important myiasis in livestock and also, occasionally, in humans:{{citation needed|date=July 2020}}
* [[Calliphoridae]] (blowflies)
** Some examples include ''[[Calliphora vomitoria]]'', ''Calliphora vicina'', and ''[[Cordylobia]]''
* [[Oestridae]] ([[Botfly|botflies]])
* [[Sarcophagidae]] (fleshflies) ''[[Sarcophaga barbata]]'' are usually found in dead and rotting meat and animal excrement, which are prime environments for them. This is because their larvae are facultative [[parasites]], as they feed on organic tissue and use the hosts' oxygen reserve.

Other families occasionally involved are:{{citation needed|date=May 2021}}
* [[Anisopodidae]]
* [[Piophilidae]]
* [[Stratiomyidae]]
* [[Syrphidae]]

====Specific myiasis====
Caused by flies that need a host for larval development:
* ''[[Dermatobia hominis]]'' (human botfly)
* ''[[Cordylobia anthropophaga]]'' (tumbu fly)
* ''[[Cordylobia rodhaini]]'' (Lund's fly)<ref>{{cite journal |last1=Tamir |first1=Jeremy |last2=Haik |first2=Josef |last3=Schwartz |first3=Eli |title=Myiasis with Lund's Fly (Cordylobia rodhaini) in Travelers |journal=Journal of Travel Medicine |date=8 March 2006 |volume=10 |issue=5 |pages=293–295 |doi=10.2310/7060.2003.2732 |pmid=14531984 |s2cid=21353772 |doi-access=free }}</ref>
* ''[[Oestrus ovis]]'' (sheep botfly)
* ''[[Hypoderma (fly)|Hypoderma]]'' spp. (cattle botflies or ox warbles)
* ''[[Gasterophilus]]'' spp. (horse botfly)
* ''[[Cochliomyia hominivorax]]'' (new world screwworm fly)
* ''[[Chrysomya bezziana]]'' (old world screwworm fly)
* ''[[Auchmeromyia senegalensis]]'' (Congo floor maggot)
* ''[[Cuterebra]]'' spp. (rodent and rabbit botfly)

====Semispecific myiasis====
Caused by flies that usually lay their eggs in decaying animal or vegetable matter, but that can develop in a host if open wounds or sores are present:
* ''[[Lucilia (fly)|Lucilia]]'' spp. (green-bottle fly)<ref name="fu">{{cite journal |last1=Cruz Clavijo |first1=Sara E. |last2=Méndez Rodríguez |first2=Iván A. |title=Furuncular myiasis—Eco-epidemiological view of a case report |journal=Infectio |date=April 2015 |volume=19 |issue=2 |pages=83–87 |doi=10.1016/j.infect.2014.02.007|doi-access=free }}</ref>
* ''[[Cochliomyia]]'' spp. (screw-worm fly) <ref name="fu"/>
* ''[[Phormia]]'' spp. (black-bottle fly)<ref>{{cite journal |last1=Abdel-Hafeez |first1=Ekhlas H. |last2=Mohamed |first2=Rabie M. |last3=Belal |first3=Usama S. |last4=Atiya |first4=Ahmed M. |last5=Takamoto |first5=Masaya |last6=Aosai |first6=Fumie |title=Human wound myiasis caused by Phormia regina and Sarcophaga haemorrhoidalis in Minia Governorate, Egypt |journal=Parasitology Research |date=October 2015 |volume=114 |issue=10 |pages=3703–3709 |doi=10.1007/s00436-015-4599-4|pmid=26122995 |s2cid=253974900 }}</ref>
* ''[[Calliphora]]'' spp. (blue-bottle fly)<ref>{{cite journal |last1=Salvetti |first1=Massimo |last2=Corbellini |first2=Claudia |last3=Aggiusti |first3=Carlo |last4=Rosei |first4=Enrico Agabiti |last5=Muiesan |first5=Maria Lorenza |title=Calliphora vicina human myiasis: a case report |journal=Internal and Emergency Medicine |date=September 2012 |volume=7 |issue=S2 |pages=135–137 |doi=10.1007/s11739-011-0720-6|pmid=22045266 |s2cid=2383454 |doi-access=free }}</ref>
* ''[[Sarcophaga]]'' spp. (flesh fly or sarcophagids)

Flesh flies, or ''sarcophagids'', members of the family ''Sarcophagidae'', can cause [[Intestine|intestinal]] myiasis in humans if the females lay their eggs on meat or fruit.<ref>{{cite journal |last1=Najjari |first1=Mohsen |last2=Dik |first2=Bilal |last3=Pekbey |first3=Gamze |title=Gastrointestinal Myiasis Due to Sarcophaga argyrostoma (Diptera: Sarcophagidae) in Mashhad, Iran: a Case Report |journal=Journal of Arthropod-Borne Diseases |date=7 November 2020 |volume=14 |issue=3 |pages=317–324 |doi=10.18502/jad.v14i3.4565|pmid=33644245 |pmc=7903363 }}</ref>

====Accidental myiasis====
Accidental myiasis is also called pseudomyiasis. It is caused by flies that have no preference or need to develop in a host but may do so on rare occasions. Transmission occurs through accidental deposit of eggs on oral or genitourinary openings, or by swallowing eggs or larvae that are on food.{{citation needed|date=July 2020}} The [[cheese fly]] (''Piophila casei'') sometimes causes myiasis through intentional consumption of its maggots (which are contained in the traditional Sardinian delicacy [[casu marzu]]).<ref>{{cite journal |doi=10.1001/jama.1952.72930200005011b |title=Intestinal Infestation with Maggots of the "Cheese Fly" (''Piophila Casei'') |date=May 17, 1952 |last1=Peckenschneider |first1=L. E. |journal=JAMA: The Journal of the American Medical Association |volume=149 |issue=3 |page=262 |pmid=14927333 |url=https://jamanetwork.com/journals/jama/article-abstract/314735 |url-access=subscription }}</ref><ref>{{cite journal|url=https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/537288|title=Gastrointestinal Myiasis – Report of a case, Alonzo F. Brand, M.D., Arch Intern Med (Chic). 1931;47(1):149–154. doi:10.1001/archinte.1931.00140190160017|journal=Archives of Internal Medicine|date=January 1931|volume=47|issue=1|pages=149–154|doi=10.1001/archinte.1931.00140190160017|access-date=17 February 2018|archive-url=https://web.archive.org/web/20180109181904/https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/537288|archive-date=9 January 2018|url-status=live|url-access=subscription}}</ref> Other flies that can accidentally cause myiasis are:<ref>{{cite journal|url=https://www.sciencedirect.com/science/article/abs/pii/S187140480900032X|title=Oral myiasis caused by Musca domestica larvae in a child|author=Sunder Singh Dogra, Vikram K. Mahajan|journal=International Journal of Pediatric Otorhinolaryngology Extra|year=2010|volume=5|issue=3|pages=105–107|doi=10.1016/j.pedex.2009.05.002|access-date=21 October 2021|url-access=subscription}}</ref><ref>{{cite journal|author1=Aydenizoz, M.|author2= Gokpınar, S.|url=http://ijvar.org/index.php/ijvar/article/view/473|title=Urogenital (by Psychoda albipennis (Diptera: Nematocera)) and Intestinal Myiasis (by Fannia canicularis (Diptera: Fanniidae)) in Kırıkkale/Turkey: Report Two Cases.|journal=International Journal of Veterinary and Animal Research|date=26 December 2020|volume=3|issue=3|pages=2020–2023|access-date=24 October 2021|eissn=2651-3609}}</ref>
* ''[[Musca domestica]]'' (housefly)
* ''[[Fannia (fly)|Fannia]]'' spp. (latrine flies)
* ''[[Eristalis tenax]]'' (rat-tailed maggots)
* ''[[Muscina]] spp.

The adult flies are not parasitic, but when they lay their eggs in open [[wound]]s and these hatch into their [[larva]]l stage (also known as [[maggot]]s or [[Larva|grub]]s), the larvae feed on live or necrotic tissue, causing myiasis to develop. They may also be ingested or enter through other body apertures.{{citation needed|date=July 2020}}

== Diagnosis ==
Myiasis is often misdiagnosed in the United States because it is rare and its symptoms are not specific. Intestinal myiasis and urinary myiasis are especially difficult to diagnose.<ref name="John 2006. p. 328-334"/>

Clues that myiasis may be present include recent travel to an endemic area, one or more non-healing lesions on the skin, itchiness, movement under the skin or pain, discharge from a central punctum (tiny hole), or a small, white structure protruding from the lesion.<ref name="Adisa 2004">{{cite journal |last1=Adisa |first1=Charles Adeyinka |last2=Mbanaso |first2=Augustus |date=2004 |title=Furuncular myiasis of the breast caused by the larvae of the Tumbu fly (''Cordylobia anthropophaga'') |journal=BMC Surgery |volume=4 |page=5 |doi=10.1186/1471-2482-4-5 |pmc=394335 |pmid=15113429 |doi-access=free }}</ref> Serologic testing has also been used to diagnose the presence of botfly larvae in human ophthalmomyiasis.<ref name=lag/>

<gallery mode="packed" widths="360px" heights="160">
File:UOTW 22 - Ultrasound of the Week 1.webm|Ultrasound showing maggot infestation<ref name="UOTW22">{{cite web|title=UOTW #22 - Ultrasound of the Week|url=https://www.ultrasoundoftheweek.com/uotw-22/|website=Ultrasound of the Week|access-date=27 May 2017|date=14 October 2014}}</ref>
File:UOTW 22 - Ultrasound of the Week 2.webm|Ultrasound showing maggot infestation<ref name="UOTW22"/>
File:UOTW 22 - Ultrasound of the Week 3.jpg|Ultrasound showing maggot infestation<ref name="UOTW22"/>
</gallery>

===Classifications===
[[Germany|German]] [[Entomology|entomologist]] [[Fritz Konrad Ernst Zumpt|Fritz Zumpt]] describes myiasis as "the infestation of live human and vertebrate animals with dipterous larvae, which at least for a period, feed on the host's dead or living tissue, liquid body substances, or ingested food". For modern purposes, however, this is too vague. For example, feeding on dead or necrotic tissue is not generally a problem except when larvae such as those of [[Cheese fly|flies in the family Piophilidae]] attack stored food such as cheese or preserved meats; such activity suggests [[Saprotrophic nutrition|saprophagy]] rather than parasitism; it even may be medically beneficial in [[Maggot therapy|maggot debridement therapy (MDT)]].{{citation needed|date=January 2021}}

Currently, myiasis commonly is classified according to aspects relevant to the case in question:
* The classical description of myiasis is according to the part of the host that is infected. This is the classification used by [[ICD|ICD-10]]. For example:<ref name="isbn0-697-26071-2">{{cite book |author1=Janovy, John |author2=Schmidt, Gerald D. |author3=Roberts, Larry S. |title=Gerald D. Schmidt & Larry S. Roberts' Foundations of parasitology |publisher=Wm. C. Brown |location=Dubuque, Iowa |year=1996 |isbn=0-697-26071-2 }}</ref>
** [[dermis|dermal]]
** [[Subcutaneous tissue|sub-dermal]]
** [[cutaneous]] (B87.0)
*** creeping, where larvae burrow through or under the skin
*** furuncular, where a larva remains in one spot, causing a boil-like lesion
** [[nasopharyngeal]], in the nose, sinuses or pharynx (B87.3)
** [[Ophthalmology|ophthalmic]] or [[human eye|ocular]], in or about the eye (B87.2)
** [[Ear|auricular]], in or about the ear
** [[Stomach|gastric]], [[Rectum|rectal]], or [[intestinal]]/enteric for the appropriate part of the digestive system (B87.8)
** [[urogenital]] (B87.8)
* Another aspect is the relationship between the host and the parasite which provides insight into the biology of the fly species causing the myiasis and its likely effect. Thus the myiasis is described as either:<ref name="isbn0-697-26071-2"/>
** [[Obligate parasite|obligatory]], where the parasite cannot complete its life cycle without its parasitic phase, which may be specific, semispecific, or opportunistic
** [[Facultative parasite|facultative]], incidental, or accidental, where it is not essential to the life cycle of the parasite; perhaps a normally free-living larva accidentally gained entrance to the host<ref name="John 2006. p. 328-334"/>
Accidental myiasis commonly is enteric, resulting from swallowing eggs or larvae with one's food. The effect is called ''pseudomyiasis''.<ref>{{cite book |last=Zumpt |first=Fritz Konrad Ernst |author-link=Fritz Konrad Ernst Zumpt |title=Myiasis in man and animals in the old world |publisher=Butterworth |date=1965 |url=https://books.google.com/books?id=S4FrAAAAMAAJ&q=pseudomyiasis }}</ref> One traditional cause of pseudomyiasis was the eating of maggots of [[Piophilidae|cheese flies]] in cheeses such as [[Stilton cheese|Stilton]]. Depending on the species present in the gut, pseudomyiasis may cause significant medical symptoms, but it is likely that most cases pass unnoticed.{{citation needed|date=January 2021}}

==Prevention==
The first control method is preventive and aims to eradicate the adult flies before they can cause any damage and is called. The second control method is treatment once the infestation is present, and concerns the infected animals (including humans).{{citation needed|date=January 2021}}

The principal control method of adult populations of myiasis-inducing flies involves [[insecticide]] applications in the environment where the target livestock is kept. [[Insecticide|Organophosphorus]] or [[Insecticide|organochlorine]] compounds may be used, usually in a spraying formulation. One alternative prevention method is the [[sterile insect technique]] (SIT) where a significant number of artificially reared sterilized (usually through irradiation) male flies are introduced. The male flies compete with wild breed males for females to copulate and thus cause females to lay batches of unfertilized eggs that cannot develop into the larval stage.{{citation needed|date=January 2021}}

One prevention method involves removing the environment most favourable to the flies, such as by removal of the tail. Another example is the [[crutching]] of sheep, which involves the removal of wool from around the tail and between the rear legs, which is a favourable environment for the larvae. Another, more permanent, practice that is used in some countries is [[mulesing]], where the skin is removed from young animals to tighten remaining skin{{snd}}leaving it less prone to fly attack.<ref name = "DPI SOP">{{cite web|url = http://www.agric.nsw.gov.au/reader/aw-sheep/13-mulesing.htm|publisher = New South Wales Department of Primary Industries |date = March 8, 2004|access-date = 2007-01-09|title = Standard Operating Procedures - sheep Mulesing|work = teacher's notes}}</ref>

To prevent myiasis in humans, there is a need for general improvement of sanitation, personal hygiene, and extermination of the flies by insecticides. Clothes should be washed thoroughly, preferably in hot water, dried away from flies, and ironed thoroughly. The heat of the iron kills the eggs of myiasis-causing flies.<ref name="Adisa 2004"/>

==Treatment==
This applies once an infestation is established. In many circles the first response to cutaneous myiasis once the breathing hole has formed, is to cover the air hole thickly with [[petroleum jelly]]. Lack of oxygen then forces the larva to the surface, where it can more easily be dealt with. In a clinical or veterinary setting there may not be time for such tentative approaches, and the treatment of choice might be more direct, with or without an incision. First, the larva must be eliminated through pressure around the lesion and the use of [[forceps]]. Secondly, the wound must be cleaned and disinfected. Further control is necessary to avoid further reinfestation.{{citation needed|date=January 2021}}

Livestock may be treated prophylactically with slow-release [[Bolus (medicine)|bolus]]es containing [[ivermectin]], which can provide long-term protection against the development of the larvae. Sheep also may be [[sheep dip|dipped]], a process that involves drenching the animals in persistent insecticide to poison the larvae before they develop into a problem.{{citation needed|date=May 2021}}

==Epidemiology==
{{Main|Flystrike in sheep}}
Myiasis is prevalent in livestock, and especially in [[sheep|domestic sheep]]. Myiasis in sheep is often caused by [[Calliphoridae|blowflies]] (''[[Common green bottle fly|Lucilia sericata]]'' and ''[[Lucilia cuprina|L. cuprina]]'' in particular) and is commonly referred to as blowfly strike. Blowfly strike, and other flystrike, occurs worldwide but is most common in regions where hot and wet conditions are sustained, such as [[Sub-Saharan Africa]],<ref>{{Cite journal |last1=Kouam |first1=M. K. |last2=Meutchieye |first2=F. |last3=Miegoue |first3=E. |last4=Nguafack |first4=T. T. |last5=Tchoumboue |first5=J. |last6=Teguia |first6=A |date=Jan 2017 |title=Prevalence and husbandry-related risk factors of myiasis in domestic cavies in the western highlands of Cameroon |journal=Epidemiology and Infection |language=en |volume=145 |issue=2 |pages=339–346 |doi=10.1017/S0950268816002466 |pmid=27780497 |issn=0950-2688|pmc=9507628 }}</ref> [[Southeast Asia]],<ref>{{Cite web |title=Obligatory Myiasis-producing Flies of Animals - Integumentary System |url=https://www.merckvetmanual.com/integumentary-system/flies/obligatory-myiasis-producing-flies-of-animals |access-date=2023-05-19 |website=Merck Veterinary Manual |language=en-US}}</ref> [[Latin America]], [[Australia]], and [[New Zealand]].<ref>{{Cite journal|date=2007-05-12|title=Royal (Dick) School of Veterinary Studies|journal=Veterinary Record|volume=160|issue=19|pages=669|doi=10.1136/vr.160.19.669-b|s2cid=219190547|issn=0042-4900}}</ref> As of 2021, blowfly strike accounts for over [[Australian dollar|A$]]280&nbsp;million a year in losses for the Australian [[Sheep farming|sheep industry]].<ref name="wa.gov.au">{{Cite web |title=Managing flystrike in sheep |url=https://www.agric.wa.gov.au/livestock-parasites/managing-flystrike-sheep?nopaging=1 |access-date=2023-05-19 |website=agric.wa.gov.au |language=en}}</ref> As mitigation, Australian sheep farmers may engage in [[mulesing]], a procedure designed to remove strips of wool-producing skin that are the most common targets for flies.<ref name="wa.gov.au"/> Farmers may also [[Docking (animal)|dock]] lambs' tails to reduce the likelihood of infestation.<ref name="wa.gov.au"/> However, both mulesing and tail-docking have received criticism from [[animal welfare]] groups, who say the mitigative procedures are excessive and can have other negative effects.<ref>{{Cite web |title=What is the RSPCA's view on mulesing and flystrike prevention in sheep? |work=RSPCA Knowledgebase |url=https://kb.rspca.org.au/knowledge-base/what-is-the-rspcas-view-on-mulesing-and-flystrike-prevention-in-sheep/ |access-date=2023-05-19 |language=en-AU}}</ref> 

In addition to blowfly strike in sheep, myiasis from [[Cochliomyia|screwworm flies]] (''[[Cochliomyia hominivorax]]'' in particular) regularly cause upwards of US$100 million in annual damages to domestic [[cow]]s and [[goat]]s.<ref>{{cite book |last=Hill |first=Dennis S. |title=The economic importance of insects |year=1997 |publisher=Springer |page=102 |url=https://books.google.com/books?id=RKQIAqMyBJgC&pg=PA102 |isbn=0-412-49800-6}}</ref> Screwworm-related myiasis is primarily mitigated through the [[sterile insect technique]].<ref>{{Cite web |date=2016-04-13 |title=Sterile insect technique |url=https://www.iaea.org/topics/sterile-insect-technique |access-date=2023-05-19 |website=[[International Atomic Energy Agency]] |language=en}}</ref>

==History==
[[File:Myiasis-cat.jpg|thumb|Myiasis in a cat's flesh]]
[[File:Miyaz.jpg|thumb|Myiasis in a dog's flesh]]
[[Frederick William Hope]] coined the term ''myiasis'' in 1840 to refer to diseases resulting from dipterous larvae as opposed to those caused by other insect larvae (the term for this was ''scholechiasis''). Hope described several cases of myiasis from Jamaica caused by unknown larvae, one of which resulted in death.<ref>{{cite web|url=https://web.archive.org/web/20080911064109/http://www.nhm.ac.uk/research-curation/research/projects/myiasis-larvae/intro-myiasis/index.html |title=Introduction to myiasis |work=[[Natural History Museum, London]] |access-date=2013-11-05}}</ref>

Even though the term ''myiasis'' was first used in 1840, such conditions have been known since ancient times. [[Ambroise Paré]], the chief surgeon to [[Charles IX of France|King Charles IX]] and [[Henry III of France|King Henry III]], observed that maggots often infested open wounds.<ref name="Sherman, RA 2000">{{cite journal |vauthors=Sherman, RA, Hall, MJR, Thomas, S |date=2000 |title=Medicinal Maggots: An ancient remedy for some contemporary afflictions |journal=Annual Review of Entomology |volume=45 |pages=55–81 |doi=10.1146/annurev.ento.45.1.55 |pmid=10761570}}</ref>

==Maggot therapy==
{{Main|Maggot therapy}}
Throughout recorded history, maggots have been used [[Therapy|therapeutically]] to clean out necrotic [[wound]]s, an application known as ''[[maggot therapy]]''.{{citation needed|date=January 2021}}

Fly larvae that feed on dead tissue can clean wounds and may reduce bacterial activity and the chance of a secondary infection. They dissolve dead tissue by secreting digestive enzymes onto the wound as well as actively eating the dead tissue with mouth hooks, two hard, probing appendages protruding on either side of the "mouth".<ref name="Greer, Kathleen 2005">{{cite journal |last=Greer |first=Kathleen A. |date=January–February 2005 |title=Age-old therapy gets new approval |journal=Advances in Skin & Wound Care |volume=18 |issue=1 |pages=12–5 |doi=10.1097/00129334-200501000-00003|pmid=15716781 |doi-access=free }}</ref> Maggot therapy{{spaced ndash}}also known as maggot debridement therapy (MDT), larval therapy, larva therapy, or larvae therapy{{spaced ndash}}is the intentional introduction by a health care practitioner of live, disinfected [[Lucilia (fly)|green bottle fly]] maggots into the non-healing skin and soft tissue wounds of a human or other animal for the purpose of selectively cleaning out only the necrotic tissue within a wound to promote healing.{{citation needed|date=January 2021}}

Although maggot therapy has been used in the US for the past 80 years, it was approved by the FDA as a medical device only in 2004 (along with leeches).<ref name="usatoday">{{cite web |last=Rubin |first=Rita |url=https://www.usatoday.com/news/health/2004-07-07-leeches-maggots_x.htm |title=Maggots and leeches: Good medicine |publisher=Usatoday.Com |date=2004-07-07 |access-date=2013-11-05}}</ref> Maggots were the first live organism to be marketed in the US according to FDA regulations, and are approved for treating neuropathic (diabetic) foot ulcers, pressure ulcers, venous stasis ulcers, and traumatic and post-surgical wounds that are unresponsive to conventional therapies. Maggots were used in medicine before this time, but were not federally regulated. In 1990, California [[Internal medicine|internist]] Ronald Sherman began treating patients with maggots produced at his lab at the [[University of California, Irvine School of Medicine|UC Irvine School of Medicine]].<ref name="usatoday" /> Sherman went on to co-found Monarch Labs in 2005, which UC Irvine contracted to produce maggots for Sherman's own continuing clinical research on myiasis at the university. Monarch Labs also sells maggots to hospitals and other medical practices, the first US commercial supplier to do so since the last one closed in 1935.<ref name="Biotech HC">{{cite journal |last1=Carlson |first1=Bob |title=Crawling Through the Millennia: Maggots and Leeches Come Full Circle |journal=Biotechnology Healthcare |date=February 2006 |volume=3 |issue=1 |pages=14–17 |pmc=3571037 |pmid=23424330}}</ref>

In the US, demand for these fly larvae doubled after the FDA ruling. Maggot therapy is now used in more than 300 sites across the country.<ref name="Greer, Kathleen 2005"/> The American Medical Association and Centers for Medicare and Medicaid Services recently clarified the reimbursement guidelines to the wound care community for medicinal maggots, and this therapy may soon be covered by insurance.<ref>{{cite web |first=Robin |last=Lloyd |url=http://www.nbcnews.com/id/27808424 |archive-url=https://web.archive.org/web/20131105203505/http://www.nbcnews.com/id/27808424/ |url-status=dead |archive-date=November 5, 2013 |title=Insurance may soon cover maggot therapy |work=NBC News |date=2008-11-19 |access-date=2013-11-05}}</ref> The larvae of the green bottle fly (Lucilia fly) are now used exclusively for this purpose, since they preferentially devour only necrotic tissue, leaving healthy tissue intact. This is an important distinction, as most other major varieties of myiasitic fly larvae attack both live and dead wound tissue indiscriminately, effectively negating their benefit in non-harmful wound debridement. Medicinal maggots are placed on the wound and covered with a sterile dressing of gauze and nylon mesh. However, too many larvae placed on the wound could result in healthy tissue being eaten, efficiently creating a new wound, and rendering it a type of myiasis.<ref name="Sherman, RA 2000"/>

===History===
Maggot therapy has a long history and [[prehistory]]. The indigenous people of Australia used maggot therapy, and so do the Hill Peoples of Northern Burma, and possibly the Mayans of Central America.<ref name="John 2006. p. 328-334"/> Surgeons in Napoleon's armies recognized that wounded soldiers with myiasis were more likely to survive than those without the infestation. In the American Civil War, army surgeons treated wounds by allowing blowfly maggots to clean away the decayed tissue.{{citation needed |date=January 2021}}

William Baer, an orthopedic surgeon at Johns Hopkins during the late 1920s, used maggot therapy to treat a series of patients with osteomyelitis, an infection of bone or bone marrow. The idea was based on an experience in [[World War I]] in which two soldiers presented to him with broken femurs after having lain on the ground for seven days without food. Baer could not figure out why neither man had a fever or signs of sepsis. He observed: "On removing the clothing from the wounded part, much was my surprise to see the wound filled with thousands and thousands of maggots, apparently those of the blow fly. The sight was very disgusting and measures were taken hurriedly to wash out these abominable looking creatures." However, he then saw that the wounds were filled with "beautiful pink granulation tissue" and were healing well.<ref>{{cite journal |last=Baer |first=William S. |date=1931 |title=The treatment of chronic osteomyelitis with the maggot (larva of the blowfly) |journal=Journal of Bone and Joint Surgery |volume=13 |issue=3 |pages=438–475 |url=http://jbjs.org/content/13/3/438}}</ref>

Maggot therapy was common in the United States during the 1930s. However, during the second half of the twentieth century, after the introduction of antibiotics, maggot therapy was used only as a last resort for very serious wounds.<ref name="John 2006. p. 328-334"/> Lately maggots have been making a comeback due to the increased resistance of bacteria to antibiotics.<ref>{{cite journal |journal=[[The Lancet]] |url=https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(05)72870-1/fulltext?version%3DprinterFriendly#articleInformation |title=Maggot therapy: an alternative for wound infection |date=2000-09-30 |last=Bonn |first=Dorothy |doi=10.1016/S0140-6736(05)72870-1 |volume=356 |issue=9236 |pages=1174 |pmid=11030307 |s2cid=27100272|url-access=subscription }}</ref>

==References==
{{Reflist}}

== External links ==
* [http://en.wikivet.net/Myiasis Myiasis], reviewed and published by [[WikiVet]]
* [http://medent.usyd.edu.au/fact/myiasis.html#intro Exotic Myiasis], [[University of Sydney]] Department of Medical Entomology
* [http://www.nhm.ac.uk/research-curation/research/projects/myiasis-larvae/index.html Identification key to species of myiasis-causing fly larvae], [[Natural History Museum, London|Natural History Museum]] (London)
* [https://en.wikibooks.org/wiki/Parasitic%20Insects,%20Mites%20and%20Ticks:%20Genera%20of%20Medical%20and%20Veterinary%20Importance/Botflies Parasitic Insects, Mites and Ticks: Genera of Medical and Veterinary Importance: Botflies]
{{Medical resources
| DiseasesDB      = 29588
| ICD11           = {{ICD11|1G01}}
| ICD10           = {{ICD10|B|87||b|85}}
| ICD9            = {{ICD9|134.0}}
| ICDO            =
| OMIM            =
| MedlinePlus     =
| eMedicineSubj   =
| eMedicineTopic  =
| MeshID          = D009198
| Orphanet        = 75110
}}
{{Pediculosis, acariasis and other infestations}}

[[Category:Tropical diseases]]
[[Category:Sheep and goat diseases]]
[[Category:Arthropod infestations]]
[[Category:Veterinary entomology]]
[[Category:Parasitic infestations, stings, and bites of the skin]]