T. gondii is strictly purine auxotroph, thus unable of de novo biosynthesis of purine nucleic bases and relies on their scavenging from the host cell to meet its nutritional needs . The parasite purines are adenine, guanine, xanthine and hypoxanthine , these nucleobases being not only essential building blocks for nucleic acids synthesis, but also required for the obtainment of other metabolites and proteins, as well as in reactions necessitating energy . Yet, T. gondii scavenges and synthesizes pyrimidine nucleobases and nucleosides .