Human bot fly

Taxobox


image_caption = Adult female human bot fly
name = Human Bot Fly
regnum = Animalia
phylum = Arthropoda
subphylum = Hexapoda
classis = Insecta
subclassis = Pterygota
infraclassis = Neoptera
superordo = Endopterygota|
ordo = Diptera
subordo = Brachycera
infraordo = Muscomorpha
zoosectio = Schizophora
zoosubsectio = Calyptratae
superfamilia = Oestroidea
familia = Oestridae
subfamilia = Cuterebrinae
genus = "Dermatobia"
species = "D. hominis"
binomial = "Dermatobia hominis"
binomial_authority = (Linnaeus Jr in Pallas, 1781)
synonyms = "Oestrus hominis"Linnaeus Jr in Pallas, 1781The genus "Dermatobia" contains only one species, "D. hominis", the only species of bot fly that attacks humans (in addition to a wide range of other animals, including other primatescite web |url=http://chppm-www.apgea.army.mil/documents/FACT/HumanBotFlyMyiasisJTFAug2007.pdf |title=Human Bot Fly Myiasis |accessdate=2008-10-09 |publisher=U.S. Army Center for Health Promotion and Preventive Medicine |month=August |year=2007] ). It is also known as the torsalo or American warble fly, even though the Warble fly is in the genus "Hypoderma" and not "Dermatobia" and is a parasite on cattle and deer instead of humans. "Dermatobia" fly eggs are vectored by mosquitoes and muscoid flies; the female captures the mosquito and attaches its eggs to the body of it, then releases it. Either the eggs hatch while the mosquito is feeding and the larvae use the mosquito bite area as the entry point, or the eggs simply drop off the muscoid fly when it lands on the skin. The larvae develop inside the subcutaneous layers, and after approximately eight weeks, they drop out to pupate for at least a week, typically in the soil. The adults are small gray flies resembling a blowfly.

This species is native to Mexico and Central America, though it is not abundant enough (nor harmful enough) to ever attain true pest status. Since the fly larvae can only survive the entire eight-week development if the wound does "not" become infected, it is rare for patients to experience infections unless they kill the larva without removing it completely (below). It is even possible that the fly larva may itself produce antibiotic secretions that help prevent infection while it is feeding.

Remedies

The bot fly maggot cannot be removed easily while alive due to the strong, hooked spines that run in circular rings around the midsection of its body. However, various solutions have been suggested:

*Immediate contact with larvae can be remedied with alcohol.Fact|date=October 2008

*Recently, physicians have discovered that venom extractor syringes can remove larvae with ease at any stage of growth. As these devices are a common component of first-aid kits to deal with snakebites, this is an effective and easily accessible solution. [cite journal |first=Andrea K. |last=Boggild |coauthors=Jay S. Keystone and Kevin C. Kain |title=Furuncular myiasis: a simple and rapid method for extraction of intact Dermatobia hominis larvae |journal=Clinical Infectious Diseases |volume=35 |issue=3 |pages=336–338 |year=2002 |month=August |pmid=12115102 |doi=10.1086/341493 |url=http://www.journals.uchicago.edu/cgi-bin/resolve?CID011565 |accessdate=2008-10-09]

*A larva has been successfully removed by first applying several coats of nail polish to the area of the larva's entrance, weakening it by partial asphyxiation.cite journal |first=Ramanath |last=Bhandari |coauthors=David P. Janos and Photini Sinnis |title=Furuncular myiasis caused by Dermatobia hominis in a returning traveler |journal=The American journal of tropical medicine and hygiene |volume=76 |issue=3 |pages=598–9 |year=2007 |month=March |pmid=17360891 |pmc=1853312 |doi= |url=http://www.ajtmh.org/cgi/pmidlookup?view=long&pmid=17360891 |accessdate=2008-10-09]

*Covering the location with duct tape would also result partial asphixiation and weakening of the larva, but is not recommended because the larva's breathing tube is fragile and would be broken during the removal of the duct tape, leaving most of the larva behind.

*Some people have reported success simply by careful application of pressure, but this approach runs a very high risk of killing the larva "in situ", leading to infection. One medical treatment is to suffocate the grub by sealing off the air hole found in the surrounding blister. This can be done with petroleum jelly or a similar substance. This forces the grub to expose itself temporarily (to clear the spiracles), making it easier to remove, though it is still risky if the larva does not come completely out of the wound and therefore is not a simple matter to perform without killing the larva and causing infection. Most commonly, people will snap off the tail of the larva, leaving the portion with the hooks still embedded.Fact|date=October 2008

*A similar "cure" (which is really more of a folk remedy) is to put meat over the affected area while the flies are in their larval stage, thereby cutting off the parasites' air supply. The grubs should then burrow through the meat to gain access to oxygen, at which point the meat may be removed with the larvae trapped inside. It is unclear, however, whether this is generally effective, and controlled experiments have not been done to determine precisely which "home-grown" method of extraction is safest, most effective, or easiest. Surgical removal is an option, of course, but could be costly for those without access to affordable health care.Fact|date=October 2008

*In general, then, simply allowing the larva to develop and leave the body on its own is the safest and least risky course of action, though few people are willing to wait that long, especially if the larva is lodged in an uncomfortable or unsightly location. The degree of discomfort experienced does seem to be entirely dependent on where the larva is located, related to how sensitive the surrounding tissue is.Fact|date=October 2008

ee also

*Myiasis

References

External links

* [http://www.davesgonemental.com/?p=50 Personal account of a botfly larva and extraction, with video and close-up photos showing mouth action]
* [http://www.aafp.org/afp/20050401/letters.html Case Report: Insect Bite Reveals Botfly Myiasis in an Older Woman]
* [http://humanbotfly.blogspot.com/ Personal blog featuring facts and stories]
* [http://www.liveleak.com/view?i=b466093a94 Video of live botfly larvae extraction from back of human host]
* [http://domandnat.com/albums/South_America/Venezuela/_ICT4060.jpg.html Young botfly larvae (about 3 weeks old) just minutes after having been extracted from an arm]
* [http://creatures.ifas.ufl.edu/misc/flies/human_bot_fly.htm human bot fly] on the UF / IFAS Featured Creatures Web site

*cite journal |author=Sampson CE, MaGuire J, Eriksson E |title=Botfly myiasis: case report and brief review |journal=Annals of plastic surgery |volume=46 |issue=2 |pages=150–2 |year=2001 |month=February |pmid=11216610 |doi= |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0148-7043&volume=46&issue=2&spage=150 |accessdate=2008-10-09
*cite journal |author=Schwartz E, Gur H |title=Dermatobia hominis myiasis: an emerging disease among travelers to the Amazon basin of Bolivia |journal=Journal of travel medicine : official publication of the International Society of Travel Medicine and the Asia Pacific Travel Health Association |volume=9 |issue=2 |pages=97–9 |year=2002 |pmid=12044278 |doi=10.2310/7060.2002.21503 |url= |accessdate=2008-10-09
*cite journal |author=Passos MR, Barreto NA, Varella RQ, Rodrigues GH, Lewis DA |title=Penile myiasis: a case report |journal=Sexually transmitted infections |volume=80 |issue=3 |pages=183–4 |year=2004 |month=June |pmid=15169999 |pmc=1744837 |doi= |url=http://sti.bmj.com/cgi/pmidlookup?view=long&pmid=15169999 |accessdate=2008-10-09
*cite journal |author=Denion E, Dalens PH, Couppié P, "et al" |title=External ophthalmomyiasis caused by Dermatobia hominis. A retrospective study of nine cases and a review of the literature |journal=Acta ophthalmologica Scandinavica |volume=82 |issue=5 |pages=576–84 |year=2004 |month=October |pmid=15453857 |doi=10.1111/j.1600-0420.2004.00315.x |url=http://www3.interscience.wiley.com/cgi-bin/fulltext/118808679/HTMLSTART |accessdate=2008-10-09