RSS Feeds
Myiasis in a Traveler: A Moving Story
- Joshua P. Fogelman, MD;
- Doris J. Day, MD; and
- Robert J. Cohen, MD
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
TO THE EDITOR:
Case Report: A 22-year-old man presented to the Bellevue Hospital Clinic of the New York University Department of Dermatology with four painful nodules on the gluteal region. The patient first noted these nodules, which had been present for 5 months, during travel through South America. He reported no fever, chills, or other symptoms. One month earlier, in an emergency department, he had received oral cephalexin for bacterial furunculosis, but symptoms and signs were not relieved.
On physical examination, four tender, indurated, erythematous nodules measuring approximately 0.5 cm were noted, each with a central punctum draining serosanguinous exudate. On 10× magnification, movement of foreign bodies was observed. After many attempts to asphyxiate and thereby lure the foreign bodies from the nodules by occluding the puncta with petrolatum, elliptical excisions were made and a single yellow larva, measuring approximately 1.5 cm × 0.8 cm × 0.7 cm, was extracted from each nodule (Figure on page 522). The patient was treated with oral cephalexin for 14 days and received topical wound care with bacitracin ointment. His symptoms quickly improved, and the nodules resolved fully without complication.
Discussion: Myiasis is the cutaneous infestation of humans or other vertebrates with larvae of dipterous (two-winged) flies, which consume the host's living or necrotic tissue (1). There are two types of cutaneous infestation: a superficial infestation, producing wound myiasis, and infestation of the subcutis, causing furuncular myiasis. Botfly myiasis is caused by the larvae of Dermatobia hominis, the tropical botfly or warble fly, which is found mainly from central Mexico to Argentina (2). Dermatobia hominis myiasis has not been reported in the United States as a primary infection (3), and all U.S. cases in the medical literature have been contracted during international travel (4).
The tropical botfly infests human and animal hosts through phoresis, a unique egg-delivery method through which the gravid female D. hominis fly oviposits and literally glues eggs to the abdomen of a blood-sucking arthropod, usually a day-flight mosquito of the Psorophora or Stomoxys species. These species act as “carriers” that feed on vertebrates, with humans as accidental hosts of the three-stage larval cycle. Dermatobia hominis eggs hatch on contact with warm-blooded hosts, and the first-stage larvae invade the skin through the site of the carrier insect's blood meal. After the individual larva has fully entered the skin, it develops through its second and third larval stages. In the process, a nodule develops with a central punctum that communicates with the surface. Approximately 5 to 10 weeks after initial skin penetration, the third-stage larva emerges from the punctum to pupate in soil, developing into an adult botfly in approximately 4 to 11 weeks (1).
In humans, the clinical lesions of myiasis occur at the site of the blood-sucking insect's bite, usually on exposed skin. Lesions vary from an initial pruritic, erythematous papule, similar to a typical mosquito bite, to the more advanced, tender, erythematous nodule with a punctum. The larval spiracle (breathing apparatus) may be visible at the punctum and can be a key clinical sign for diagnosis. The major differential diagnosis is furunculosis. Symptoms include malaise, localized pruritus, pain, and a crawling sensation; laboratory abnormalities include leukocytosis and eosinophilia (1, 2, 3, 5). Oral antibiotics to treat bacterial furunculosis will not cure the parasitic infestation but will treat the secondary infection.
Treatment of human cutaneous botfly myiasis varies. Local hypoxia (suffocation of the larvae) has been used to force egress for subsequent physical extraction; to accomplish this, the puncta have been occluded with various substances, including bacon, chewing gum, sticking plaster, and petrolatum (1, 5). Surgical treatment with local anesthesia and scalpel excision is definitive. After extraction, systemic antibiotic therapy may be prescribed to control secondary infection (1, 5).
Our report demonstrates the importance of a detailed history, including a history of travel. Since international travel has increased, physicians in nontropical areas must consider imported diseases in the differential diagnosis of a globetrotting patient's symptoms and signs (3). As demonstrated by the initial diagnosis of this patient's lesions as furunculosis, cutaneous myiasis may be overlooked in nonendemic regions, especially if it is not suspected.
Joshua P. Fogelman, MD
Doris J. Day, MD
Robert J. Cohen, MD
New York University School of Medicine; New York, NY 10016
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
- Copyright ©2004 by the American College of Physicians
