PTGS1 and parasitic infectious disease: Interestingly, whereas Cox1 was positively correlated with parasitemia in the E6.5 infection group, no significant malaria-induced upregulation for either Cox1 or Cox2 relative to uninfected placenta was detected in the E10.5 infection group at E17.5 or in the E6.5 infection at E15.5, both sampled one day prior to expected preterm delivery.