Abstract: The present invention relates to immunogenic Toxoplasma gondii proteins, to T. gondii nucleic acid molecules, including those that encode such proteins and to antibodies raised against such proteins. The present invention also includes methods to obtain such proteins, nucleic acid molecules and antibodies. Also included in the present invention are compositions comprising such proteins, nucleic acid molecules and/or antibodies, as well as the use of such compositions to inhibit oocyst shedding by cats due to infection with T. gondii. The present invention also includes the use of certain T. gondii-based antisera to identify such nucleic acid molecules and proteins, as well as nucleic acid molecules and proteins identified by such methods. The present invention also relates to novel methods for the detection of cysts and oocysts.