The Human Botfly Bubbling Sign: Ultrasound Features of Cutaneous Furuncular Myiasis

Abstract

Dermatobia hominis, the human botfly, is native to South and Central America with cases of infestation seen in travelers to these areas. Myiasis is the cutaneous manifestation of larvae between two periods of molting (instar) and presents as a firm furuncular mass with a central pore that can be easily clinically overlooked. Ultrasound is useful in the diagnostic workup and has specific features and techniques to demonstrate live larva. We present a patient who acquired cutaneous furuncular myiasis caused by D. hominis, the human botfly, during her jungle trek in the Amazon forests in South America. Over 5 weeks, she developed a firm furuncular lesion with a central pore. Ultrasound revealed a hypoechoic mass with a hyperechoic oblong-shaped core that showed a fluid circulation, confirming the presence of a viable larva. Surgery was performed and a second-instar D. hominis larva was confirmed. We discuss the key ultrasound findings and management of cutaneous furuncular myiasis with the aim of raising awareness of this condition, adding to the growing body of literature likely associated with the re-opening of global travel routes.