ABSTRACT
A domesticated system is a species that can be bred in the laboratory, standardized in terms of size, age, or physiological conditions, and made to produce predictable supplies of teaching or research material on schedule. In the case of parasites, a domesticated system must include not only the parasite, but also its host, and both must be capable of being standardized and manipulated. In spite of their scientific name (Felis domesticus), housecats are not themselves very domesticated, so the name is probably a misnomer. A cattapeworm combination is probably more of a domesticated system than the cat alone because tapeworm numbers can be manipulated, and the worms are long-lived, so that the two organisms together average out higher on the manipulation scale than the cat by itself. Of course in this reference to housecats I’m being somewhat facetious, although cats easily become feral-indicating the ease with which they revert to the wild state-and a single infected cat could supply tapeworm eggs daily for months on end, probably more reliably than it could supply affection and obedience. As for helminth parasites, the rat tapeworm, Hymenolepis diminuta, is perhaps the most studied and most well understood, simply because both it and its host can be bred, standardized, and manipulated so easily in the lab. The rat-H. diminuta combination is an excellent example of a domesticated system.
