First Report of Myiasis Caused by Cochliomyia hominivorax (Diptera: Calliphoridae) in a Diabetic Foot Ulcer Patient in Argentina
A male patient aged 54 years, who is now living in Monteros City, Tucuman Province, Argentina, checked into the Angel C. Padilla Hospital in San Miguel de Tucuman for a consultation due to an ulcerous lesion in his right foot with a sanious bottom and fetid odour (). The clinical examination revealed that the ulcer contained fly larvae (n=5) with an evolution of approximately 2 days.\nThe lesion had a circular shape with a diameter of approximately 4 cm; the edge showed signs of inflammation, and the content consisted of foul-smelling necrotic tissues with a sanious bottom that corresponded to the deep aponeurosis of the wound ().\nThe patient was diagnosed with grade II diabetes (under treatment with oral hypoglycemic drugs) with a disease of over 10 years of evolution, in which the neuropathic compromise predominated with an important loss of sensibility in the area (no pain), which was the reason for delayed consultation. However, the presence of peripheral pulses was determined, which indicates that the blood flow in the compromised limb was preserved. The first surgical debridement was performed in the hospital emergency services unit. During this operation, the larvae were mechanically extracted using a sulphuric ether solution (). Tissue samples were extracted for culturing, germ identification, and antibiogram tests.\nThe patient received treatment considering his basic disease (diabetes) with broad-spectrum antibiotics until the results of the cultures were obtained. Additionally, periodic cleaning of the wound and dressing changes were conducted every other day with gauze wetted in a physiological solution. The wound, as well as the patient's metabolic values, exhibited a favourable evolution. He was discharged from the hospital after 15 days, during which time surgical debridement was performed twice. The larval specimens were taken to the laboratory of the Instituto Superior de Entomologia "Dr. Abraham Willink", Facultad de Ciencias Naturales e Instituto Miguel Lillo (Universidad Nacional de Tucuman), where they were identified and later raised individually in flasks and fed beef liver ().\nThe collected larvae belong to the species C. hominivorax with the following external morphological characters: cylindri cal, segmented, white yellow-coloured body, and tracheas with strong pigmentation that was visible until the third or fourth larval segment immediately preceding the end portion of the body [].\nAfter 2 days, the larvae reached the pupal stage and were transferred to plastic cups containing vermiculite. The cups were covered with mosquito netting. The humidity was controlled by spraying water, and the temperature was maintained at 27℃. After 12 days, the adult insects emerged. The adults were then killed, mounted, and identified using the guidelines described by Mariluis and Schnack []. The adults were also identified as C. hominivorax, which is a species that had not been previously reported in Tucuman Province, Argentina []. The morphological characters that defined the adult species were as follows: setose basal vein in the upper surface of the wing, denuded lower surface of the wing, short and reduced palps, and parafrontalia with black hairs outside the front row of setae ().