How do I get infected with toxoplasmosis?
Most people get infected with toxoplasmosis by eating undercooked meat or meat products such as lamb, beef, or game (including salami), having contact with soil, or by inhaling or swallowing infected cat litter.
When cats (and only cats) become infected with toxoplasmosis, they harbor the toxoplasma "oocytes" in their intestines. These oocytes are excreted through their feces into the cat litter. This is the so-called 'intestinal phase' of the toxoplasma life cycle and it only occurs in cats (wild as well as domesticated cats). The oocytes can be inhaled or swallowed and infect others, or if the cat feces goes into the earth, people and other animals can get it when the soil gets into their mouths.
The extraintestinal phase occurs in all infected animals (including cats) who come in contact with the oocytes. Infected animals (including humans) produce "tachyzoites" and, eventually, "bradyzoites" or "zoitocysts." These tacgyzoites, bradyzoites, and zoitocysts reside in muscle, and when you (or other animals) eat undercooked meat, you can get infected.
You can also get infected with toxoplasma by putting infected soil into your mouth (always wash your hands!) or by eating undercooked meat (including salami and other similar foods) from an animal who has become infected. Cats are the only animals excreting the oocytes in their feces.