Toxoplasmosis is caused by the single-celled parasite Toxoplasma gondii, which has a complex life cycle in which sexual and asexual reproduction alternate in different hosts.
Toxoplasma is an intestinal coccidian of cats, cats and other felids are the definitive hosts for this coccidian and the parasite rarely causes health problems in them.
In other hosts (birds and mammals, including humans) the protozoan can cause clinical problems and disease, rarely fatal.
