Trojan Pathway of Infection
This term describes a hidden, but persisting, extremely low-graded infection of a host, which does not show any clinical signs but contains a small number of transmittable stages (e.g., tissue cysts of Besnoitia besnoiti, Toxoplasma gondii or single cystozoites of Cystoisospora species (e.g., C. suis, C. felis).
The descriptive name of this transmission is based on the tale of the Greek poet Homer on the so-called Trojan War, during which Greek aggressors at first could not enter the city of Troja. Thus they left behind a wooden horse with hidden soldiers inside, who finally at night opened the doors of Troja after the horse had been transported into the town.
Transferring this tale to parasitology, the different parasites are spread in a similar way, when symptomless, but infected host animals are traded and thus transported to regions where a given parasite is not yet endemic.