Answer to Case 698

 Answer to Parasite Case of the Week 698: Cutaneous/furuncular myiasis due to Cordylobia anthropophaga (a.k.a. the tumbu or mango fly). As nicely described by Florida Fan, the spiny body, sinuous posterior slits without distinguishable peritreme, and the geographic location all are consistent with C. anthropophaga. Idzi P. added that "the evenly distributed and pigmented cuticular spines are also supportive of this identification." The presence of 3 slits indicates that this is a third stage larva, which allows for identification using commonly-available identification keys. 

Here is a closer view of the posterior spiracles, showing the characteristic posterior slits:

Cordylobia anthropophaga has a fascinating life cycle. The adult female fly lays 500-700 eggs at a time in dry soil contaminated with urine and feces. They have also been known to lay their eggs on clothing that are hung out to dry. Larvae hatch from the eggs and can remain alive in the environment for up to 2 weeks, residing just below the surface of the soil . When the soil is disturbed by a potential host, the larvae quickly emerge, and each can penetrate the skin of the host and create a cavity in which to live, feed, and mature. The posterior end of the larva faces outward within the resultant furuncle to allow for respiration through the posterior spiracles. Larvae go through 3 stages (referred to as L1, L2, L3) over a period of 8 or more days, and will then drop from the host and pupate in the environment. In warm climates, the adult fly hatches after 10-11 days.

I will always remember the story from a family member who went on a lavish African safari several decades ago and was somewhat embarrassed when the housekeeper insisted on ironing her undergarments after they had been hanging on the line to dry. When she told the housekeeper not to bother, she was very quickly informed why this was necessary - in very graphic detail! (You can see a rather disturbing case of furuncular myiasis of the breast HERE).

Thanks again to Dr. Richard Bradbury for donating this fascinating case.