Table 1.

Response of drug-exposed Plasmodium berghei ANKA strain to piperaquine and lumefantrine

Drugs used to treat mice infected with lumefantrine- and piperaquine-exposed P. berghei ANKA
	Lumenfantrine (LU)			Piperaquine (PQ)
	Parent strain	LU-exposed strain at passage 2	LU-exposed strain at passage 22	Parent strain	PQ-exposed strain at passage 2	PQ-exposed strain at passage 18
ED 50 b (mg/kg)	1.67a	93.31	1.83	1.30	85.97	81.06
I 50 c	1.00	55.87	1.09	1.00	66.13	62.35

Results are presented as effective doses that reduce parasitaemia by 50% (ED₅₀) and as 50% indices of resistance (I₅₀).

Drug responses (50% effective doses, ED_50s) as well the respective 50% indices of resistance (I_50s) of lumefantrine (LU)- and piperaquine (PQ)-exposed Plasmodium berghei ANKA in mice at initial stages of passaging (passage 2) and at the end of passaging (passage 22 and 18 for LU-exposed and PQ-exposed respectively).

^aThe ED₅₀ of the parent strain from which both LU- and PQ-exposed strains were generated is included for comparison. ^bData are presented as effective doses that reduced parasitemia by 50% (ED₅₀). ^cIndices of resistance (I_50, defined as the ratio of the ED₅₀ of the resistant line to that of the parent strain) confirm that artificially-induced PQ-resistance is stable.