Answer: Yes, this recommendation has certainly been made. The problem that the minute protozoan parasite responsible for toxoplasmosis, called Toxoplasma Gondi, can infect not only the cat but variety of other species. In all of them some multiplication of the parasite occurs (called asexual reproduction) but not in the cat does it undertake sexual reproduction to produce a stage which the cat passes out in its faces (an oocyst), and which, after above five days’ development, is able to infect other animals. Because of this, the cat is known as the final host of the parasite. The other species which become infected, but don’t themselves produce infective stages, are called intermediate hosts. These intermediate hosts include many different animals; for example, the dog, cattle, sheep the pig, rodents, birds and humans.
In addition two other features serve to make Toxoplasma even more widespread. The first is that, although the intermediate hosts don’t excrete the parasite, it can transfer from one to the other along a food chain. So that a dog eating an infected mouse, or a man eating raw steak or uncooked ham prepared from an infected animal, will in turn become infected. The second point is that in female intermediate hosts (though not in the cat itself) during pregnancy Toxoplasma can transfer from the tissue of the mother to those of her offspring whilst they are in the uterus (womb) and may damage them. In same species this congenital transmission of infection may continue for several generations. The cat itself is usually infected by infected rodents or birds.
In both the cat and the intermediate hosts, the parasites are generally present in the lungs, brain, eyes, heart and skeletal muscles. If the host has a very little immunity, multiplication of the parasite occurs rapidly producing an acute phase. But after a time the host develops an immunity, with the result that the rate of multiplication slows down and the parasite become localized in cysts in the tissue. These cysts may remain intact throughout the life of the host and cause no harm. With time, however, the immunity will decline, and if the animal should then be exposed to stress the cysts can break down, releasing the parasites and causing another acute phase (i.e. a relapse). Clinical signs of acute toxoplasmosis (e.g. fever, pneumonia nervous signs) rarely appear, but occasionally a host mat die, or suffer severe injury, because the multiplying parasites have destroyed a significant number of cells one of the vital organs of the body.
By checking for antibodies against Toxoplasma, it is estimated that at least one-third of the cat in Britain and the United States have been infected at some time in their lives. Approximately half a billion humans around the would have also been infected, and in certain areas, such as central France, the infection involves 90% of adults. Infected cats only shed oocysts for about two weeks, but darning that time several million can be shed.
