Toxoplasma gondii and Neospora caninum are obligate intracellular coccidian parasites affecting
human and animal health worldwide. They share important biological features and closer gene
structure similarity in comparison with other apicomplexan parasites [29]. However, they exhibit
substantial differences in pathogenesis, host range, and replicative life cycle. Both have a
facultative heteroxenous life cycle with cattle or sheep as an intermediate host. T. gondii is a
zoonotic parasite that infects nearly one-third of the human population and can infect almost all
warm-blood animals whilst N. caninum has been described to only infect animals even when
some seropositive human has been found [20]. Especially in humans and sheep, prenatal
infections may cause abortion or severely affect progeny welfare. Acute T. gondii infections in
Immuno-compromisedimmunocompromised patients may become life-threatening and several studies postulate a
correlation between latent T. gondii infections and neurological/psychiatric disorders in humans.
Recent studies confirmed the significant occurrence of T. gondii in the German human population.