Answer to the Parasite Case of the Week 621: Poikïlorchis (Achillurbainia) congolensis.
Wow, I am so impressed with how many of you got this identification. This rare parasite was first described in Nature in 1957 in a man from the Belgian Congo.
From Idzi: Poikilorchis congolensis, or alternatively Achillurbainia congolensis -as the genus Poïkilorchis (Fain and Vandepitte, 1957) was regarded by Dollfus as a synonym of Achillurbainia (Dollfus, R. P., 1966. Personal communication).
As far as I have found in the literature, it has been described in humans only eight times up ‘till now, although some authors suggest that some of the reported cases of Paragonimus (especially in Africa) could be in fact cases of Poïkilorchis infection.
Although its hosts are not known for sure, Poïkilorchis congolensis is considered to be a zoonosis, with the common final host probably being leopards (and maybe also giant rats?) and intermediate hosts being probably freshwater crabs.
The infection typically produces subcutaneous retroauricular cysts, which contain as well the eggs as the adults. Nevertheless, in many (human) cases only eggs are found in the cyst.
In the literature, I found human cases in Central and West Africa, Sarawak (Malaysia), possible also one in China…