NOS2 and infection: The Pearson correlation coefficient calculation between the parasite burden and the cytokine level in the liver and spleen after IV or IP infections revealed that there was a significantly strong and moderate positive correlation between the parasite burden and iNOS expression level in the liver and spleen after IV infection, respectively [liver: r(12) = 0.78, r2 = 0.60, P = 0.003; spleen: r(12) = 0.63, r2 = 0.39, P = 0.03].