NOS2 and malaria: Host components have been linked to low levels of NO during malaria: free haemoglobin, from burst of infected erythrocytes or intravascular hemolysis, which scavenges NO [57]; the activation of arginase, in infected or uninfected erythrocytes, which catalyzes the production of ornithine and urea from l-Arg [58]; the presence of endogenous iNOS inhibitors such as methylated arginines (asymmetric dimethylarginine [ADMA] and symmetric dimethylarginine [SDMA] [59]); the decreased levels of tetrahydrobiopterin, which uncouples iNOS [60].