This week's case is by Idzi Potters and the Institute of Tropical Medicine, Antwerp. The following object was removed from a furuncular skin lesion in a patient with recent travel to Uganda. Once they were able to keep it still (!), Idzi captured the following photographs demonstrating all of the diagnostic features. What is your identification?
Sunday, December 3, 2023
Answer to the Parasite Case of the Week 733: Cordylobia anthropophaga, myiasis causing fly larva.
Florida Fan painted an accurate picture of this parasite with his vivid description: "The mango fly, aka Tumbu fly, lays eggs on human clothing hung to dry in the sun. The Man-Eating larvae hatching eats its way into the skin of its prey. The three sinuous slits are definite identification clues. Ironing the clothes dried outdoor kills the eggs and prevent a myasis infection. The video clearly exemplifies the voracious nature of The Beast." Very apt!
The adult female fly also commonly lays her eggs on sandy soil contaminated with urine and feces. The larvae hatch and may remain viable in the soil for 1-2 weeks while seeking a host. Upon contact with a suitable host, the larvae burrow into the skin of the host and develop for 8-12 days. They then emerge from the host and develop into pupae in the environment.
Extracted larvae can be identified based on the characteristics of their posterior spiracules, as well as their general body characteristics. There are several keys available for genus and species-level identification, including this older key from the CDC. Blaine Mathison and I also published a review on arthropod identification which you may find helpful.
Along with this case, Idzi provided some great photos from previous posts for comparison:
Corydylobia rodhaina (Case of the Week 547):
Lastly, I'd encourage you to check out ITM's outstanding new podcast series entitled Transmission. Thanks again to Idzi and ITM for this great case!