- Email: [email protected]
Human botfly
The American Journal of Surgery 185 (2003) 256 –257
Clinical image
Human botfly John Q.A. Mattern, D.O.a, Adrian Barbul, M.D.a,b,* a
Department of Medicine and Department of Surgery, Johns Hopkins University School of Medicine/Sinai Hospital, Baltimore, MD, USA b Sinai Hospital, 2435 W. Belvedere Ave., Suite 42, Baltimore, MD 21215, USA Manuscript received May 17, 2002; revised manuscript September 1, 2002
A 29-year-old-man presented to the department of surgery complaining of intermittent bleeding and nocturnal right leg pain for approximately 6 weeks. The patient had visited the rainforests of Costa Rica and recalled being bitten by an insect in the vicinity of the lesion he had on his right leg. Two weeks after returning from Costa Rica, the bleeding began, and he also reported some pain, pruritus and a “crawling” sensation that occurred primarily at night. He reported using a topical steroid cream to help with the pruritus but the symptoms persisted. On examination of the patient’s leg, erythema and a small induration with a central orifice (Fig. 1) was noted with a white larva protruding from it. The larva (Fig. 2) was extracted uneventfully using forceps, and the central orifice healed by second intention. The patient had cutaneous myiasis caused by the human botfly, Dermatobia hominis, which is an endemic parasitic infection found in Mexico, Central America, and South America. The botfly is the most commonly encountered myiasis-causing dipteran in Central America [1]. Human botfly is an obligatory larva, requiring living tissue as a food source to complete its life cycle [2]. Interestingly, the gravid female captures another arthropod (usually mosquitoes) and lays an egg on this vector, which ultimately transports the egg to an animal or human host [3]. When the insect takes a blood meal, the heat from the host causes the egg to hatch and the larva painlessly penetrates the skin [4]. The larva requires oxygen to breath and maintains a breathing pore. The larva develops through three stages, or instars, for approximately 5 to 10 weeks, at which time it exits and drops to the ground and pupates, developing into an adult fly in approximately 2 weeks [5]. The diagnosis of myiasis hinges on the history and physical examination. The differential diagnosis can include penetrating wounds, cellulitis, insect bites, and leishmaniasis. The history of being bitten by an insect in an endemic * Corresponding author. Tel.: ⫹1-410-601-5843; fax: ⫹1-410-6015835. E-mail address: [email protected]
Fig. 1. The central orifice surrounded by erythema.
region and the time frame of symptoms provide evidence of botfly infection. A patient’s complaint of a crawling sensation under the skin and pruritus should prompt the physician to consider myiasis. The indurated, erythematous skin with a central orifice is a good physical sign to correlate with the history. Most patients will seek medical attention before the larva exits the skin. To make the diagnosis it is important to obtain the larva and have it examined by a pathologist, state medical laboratory, or entomologist. The larva usually mea-
0002-9610/03/$ – see front matter © 2003 Excerpta Medica Inc. All rights reserved. doi:10.1016/S0002-9610(02)01368-5
J.Q.A. Mattern and A. Barbul / The American Journal of Surgery 185 (2003) 256 –257
257
and entice it to surface searching for air [1,3]. When the larva surfaces, gentle manipulation or use of forceps can be used to extract the organism from its cavity. Surgery is commonly used, especially in cases involving the periorbital region, and surgery also allows complete resection of the larva and debridement of the cavity [6]. After removal, the orifice heals in a few days by second intention without any sequelae.
References
Fig. 2. The human botfly larva, Dermatobia hominis.
sures 2 cm to 3 cm and has black spines circumscribing its abdomen. A stereomicroscope can be used to better visualize the spines. Treatment is removal of the organism. Several techniques are available to extract the larva. Some have recommended placing petroleum jelly, beeswax, pork fat, or chewing gum over the breathing hole to suffocate the larva
[1] Richards KA, Brieva J. Myiasis in a pregnant woman and an effective, sterile method of surgical extraction. Dermatol Surg 2000;26:955–7. [2] Sherman RA. Wound myiasis in urban and suburban United States. Arch Intern Med 2000;160:2004 –14. [3] Hecht JL, McLaughlin M, Granter SR. Botfly infestation. Arch Pathol Lab Med 2001;125:453. [4] Sampson CE, MaGuire J, Eriksson E. Botfly myiasis: case report and brief review. Ann Plast Surg 2001;46:150 –2. [5] Mathieu ME, Wilson BB. Myiasis. In: Mandell GL, Bennett JE, Dolin R, editors. Principles and practice of infectious diseases. 5th ed. Philadelphia: Churchill Livingston, 2000, p 2975–7. [6] Millikan LE. Myiasis. Clin Dermatol 1999;17:191–5.
Clinical image
Human botfly John Q.A. Mattern, D.O.a, Adrian Barbul, M.D.a,b,* a
Department of Medicine and Department of Surgery, Johns Hopkins University School of Medicine/Sinai Hospital, Baltimore, MD, USA b Sinai Hospital, 2435 W. Belvedere Ave., Suite 42, Baltimore, MD 21215, USA Manuscript received May 17, 2002; revised manuscript September 1, 2002
A 29-year-old-man presented to the department of surgery complaining of intermittent bleeding and nocturnal right leg pain for approximately 6 weeks. The patient had visited the rainforests of Costa Rica and recalled being bitten by an insect in the vicinity of the lesion he had on his right leg. Two weeks after returning from Costa Rica, the bleeding began, and he also reported some pain, pruritus and a “crawling” sensation that occurred primarily at night. He reported using a topical steroid cream to help with the pruritus but the symptoms persisted. On examination of the patient’s leg, erythema and a small induration with a central orifice (Fig. 1) was noted with a white larva protruding from it. The larva (Fig. 2) was extracted uneventfully using forceps, and the central orifice healed by second intention. The patient had cutaneous myiasis caused by the human botfly, Dermatobia hominis, which is an endemic parasitic infection found in Mexico, Central America, and South America. The botfly is the most commonly encountered myiasis-causing dipteran in Central America [1]. Human botfly is an obligatory larva, requiring living tissue as a food source to complete its life cycle [2]. Interestingly, the gravid female captures another arthropod (usually mosquitoes) and lays an egg on this vector, which ultimately transports the egg to an animal or human host [3]. When the insect takes a blood meal, the heat from the host causes the egg to hatch and the larva painlessly penetrates the skin [4]. The larva requires oxygen to breath and maintains a breathing pore. The larva develops through three stages, or instars, for approximately 5 to 10 weeks, at which time it exits and drops to the ground and pupates, developing into an adult fly in approximately 2 weeks [5]. The diagnosis of myiasis hinges on the history and physical examination. The differential diagnosis can include penetrating wounds, cellulitis, insect bites, and leishmaniasis. The history of being bitten by an insect in an endemic * Corresponding author. Tel.: ⫹1-410-601-5843; fax: ⫹1-410-6015835. E-mail address: [email protected]
Fig. 1. The central orifice surrounded by erythema.
region and the time frame of symptoms provide evidence of botfly infection. A patient’s complaint of a crawling sensation under the skin and pruritus should prompt the physician to consider myiasis. The indurated, erythematous skin with a central orifice is a good physical sign to correlate with the history. Most patients will seek medical attention before the larva exits the skin. To make the diagnosis it is important to obtain the larva and have it examined by a pathologist, state medical laboratory, or entomologist. The larva usually mea-
0002-9610/03/$ – see front matter © 2003 Excerpta Medica Inc. All rights reserved. doi:10.1016/S0002-9610(02)01368-5
J.Q.A. Mattern and A. Barbul / The American Journal of Surgery 185 (2003) 256 –257
257
and entice it to surface searching for air [1,3]. When the larva surfaces, gentle manipulation or use of forceps can be used to extract the organism from its cavity. Surgery is commonly used, especially in cases involving the periorbital region, and surgery also allows complete resection of the larva and debridement of the cavity [6]. After removal, the orifice heals in a few days by second intention without any sequelae.
References
Fig. 2. The human botfly larva, Dermatobia hominis.
sures 2 cm to 3 cm and has black spines circumscribing its abdomen. A stereomicroscope can be used to better visualize the spines. Treatment is removal of the organism. Several techniques are available to extract the larva. Some have recommended placing petroleum jelly, beeswax, pork fat, or chewing gum over the breathing hole to suffocate the larva
[1] Richards KA, Brieva J. Myiasis in a pregnant woman and an effective, sterile method of surgical extraction. Dermatol Surg 2000;26:955–7. [2] Sherman RA. Wound myiasis in urban and suburban United States. Arch Intern Med 2000;160:2004 –14. [3] Hecht JL, McLaughlin M, Granter SR. Botfly infestation. Arch Pathol Lab Med 2001;125:453. [4] Sampson CE, MaGuire J, Eriksson E. Botfly myiasis: case report and brief review. Ann Plast Surg 2001;46:150 –2. [5] Mathieu ME, Wilson BB. Myiasis. In: Mandell GL, Bennett JE, Dolin R, editors. Principles and practice of infectious diseases. 5th ed. Philadelphia: Churchill Livingston, 2000, p 2975–7. [6] Millikan LE. Myiasis. Clin Dermatol 1999;17:191–5.