Infestation of a diabetic foot by Wohlfahrtia magnifica

Abstract

Myiasis is the infestation of animals or humans by larvae from some species of dipteran flies. Depending on the tissues invaded, the maggots of these insects can produce different diseases of the skin, or mucoses (ocular, genitourinary, and oropharyngeal). Wohlfahrtia magnifica is one of the species causing myiasis; although it is a real veterinary problem, it rarely infests humans and extraordinarily in the context we describe. We herein present the case of a diabetic patient diagnosed with class IV peripheral vascular disease (Fontaine classification) who suffered infestation by W. magnifica and the management given to this pathologic process. The patient consented to the publication of this report.

Fig 1

Macroscopic appearance of the right forefoot with several larvae readily visible in the interdigital and digitoplantar folds, epidermolysis at the base of the second and third toes, and a triangular necrotic plantar lesion.

Fig 2

Macroscopic appearance and specific features of larvae of Wohlfahrtia magnifica. A, The length reaches 13 mm. B, In the frontal view of the cephalic segment, instar III larvae exhibit a system of mouth hooks formed by only one pair of thick and long curved hooks. C, Posterior portieres of instar III. The posterior spiracle displays a button area slightly chitinized and two incomplete rings (peritremes). The peritremes have three variably shaped peritremal slits: the inner one is curved, the median one is straight and long, and the outer one is curved and long.

Fig 3

Lower limb arteriography showing diffuse vascular wall calcification, a preserved femoral tripod (upper left), and two tandem nonsignificant stenoses at the right femoropopliteal junction with a well-developed artery (upper center). The anterior tibial artery (upper right) is occluded in its middle segment and refills distally by homocollateral circulation. The peroneal artery shows a severe stenosis at its origin (upper center and right) and good caliber in all its segments. The posterior tibial artery is poorly developed and tapers in its middle third (upper right). Appearance of the right forefoot during follow-up 15 weeks (lower left) and 25 weeks (lower right) after the revascularization procedure.