Tracheopulmonary Myiasis Caused by a Mature Third-InstarCuterebraLarva: Case Report and Review

Abstract

Myiasis is the infestation of vertebrate tissues with fly larvae (Diptera). Most human cases in North America are subcutaneous forms due to Dermatobia hominis imported from Central and South America. Human cases of myiasis acquired in North America are rare and are primarily subdermal or ophthalmologic forms of infestation caused by early stages of Cuterebra larvae. We report an unusual case of tracheopulmonary myiasis, resulting from the in situ development of a mature cuterebrine larva associated with high eosinophilia. Only two other cases of tracheopulmonary cuterebrid myiasis have been reported in humans, and they are reviewed herein. Cuterebra myiasis (cuterebrosis) remains a rare and aberrant cause of tracheopulmonary disease and is a newly described cause of eosinophilia in humans. CASE REPORTIn early October 2002, a 60-year-old woman, a resident of Florida, presented in the emergency ward of Hôtel-Dieu Hospital in Paris, France. She had arrived in Europe for a vacation a week earlier, and there was no history of travel outside Florida in the previous 3 months. She reported a 3-week history of whooping cough with occasional bloody sputum, without fever. A few minutes before arriving in the emergency ward she coughed up bloody sputum which contained a large, brownish fly maggot. The larva was alive and mobile and measured 17 by 5 mm (Fig. 1). Chest auscultation and chest X-ray performed shortly after spontaneous expulsion of the maggot were normal. Additional larvae were not found after complete examination of the patient. A hemogram showed high eosinophilia (eosinophil count, 2.03 ϫ 10 9 /liter) and a white cell count of 10.4 ϫ 10 9 /liter. The level of C-reactive protein was 7 mg/liter. Detection of precipitating antibodies in the serum by a homemade method with Hypoderma lineatum and Gasterophilus antigens was negative. The day after maggot expulsion, the patient was referred to a chest specialist. Hemoptysis and cough had completely disappeared, and chest auscultation was clear. No further investigation or treatment was performed, and she reported no further complication. The larva was identified as a mature third instar (prepupal stage) in the genus Cuterebra based on size, characteristic cuticular plates and associated spines, and the posterior spiracular apparatus (Fig. 2 and 3). A more detailed examination of the external morphology revealed that the specimen was a member of the genus Cuterebra normally infesting lagomorphs (2). Because Cuterebra is restricted to the New World, and given the patient's recent travel history, we are reasonably confident that the patient was infested in Florida.

Pleural Myiasis Associated With Pleural Angiosarcoma

“…[6][7][8][9][10] Most human cases of myiasis in North America are subcutaneous infestations caused by the human botfly, Dermatobia hominis, imported from Central and South America, and the tumbu fly, Cordylobia anthrophaga, native to sub-Saharan African. 8 The larvae in our patient were identified as Calliphora species, belonging to the subfamily Calliphorinae and family Calliphoridae. 1 These flies are better known as "blow flies" and are native to the United States.…”

Myiasis

“…Tracheopulmonary myiasis is a rare manifestation of myiasis, with few published cases. It is not clear if this type of myiasis is accidental in nature, since a fully developed third-instar cuterebrid maggot was implicated in one case (72). A history of whooping cough with occasional bloody sputum, without fever, and with normal chest auscultation and chest X ray may be the clinical findings.…”

“…A history of whooping cough with occasional bloody sputum, without fever, and with normal chest auscultation and chest X ray may be the clinical findings. Tracheopulmonary myiasis in humans may be caused by the horse bot fly (7), Alouattamyia baeri (142), Megaselia spicularis (186), cuterebrids (23,72,300), and Gasterophilus sp. (7).…”

Cutaneous myiasis

“…Once in contact with the host, the eggs hatch and the first instar larvae can enter through the mucous membranes of the nose, eyes, mouth, or anus, or they may directly penetrate the skin. 51 In rabbits, the first instar larva migrates to the trachea and then enters the pleural cavity. 52 Next, the larva penetrates the diaphragm, traverses the abdominal cavity, and eventually enters the dermis.…”