 It is thought that SAICA riboside may be the more toxic compound as it is found at higher levels in patients with severe clinical symptoms, and some researchers think S-Ado may even be protective.More research needs to be done on what determines disease severity, but the instability of human ASL in the lab setting has been an obstacle to this research.As resistance to anti-malarials increases, researchers are looking for new strategies to target the "Plasmodium" parasites which cause malaria, especially the more lethal "P. falciparum".