Table 1.

Longitudinal monitoring of CQ sensitivity of P. falciparum strains in three regions of Yunnan Province using the in vitro microtest

Study sites	Year	Case No.	IC₅₀ (nM)	CMIC (nM)^*	Resistance rate (%)
Western	1982	22	480±252^a	2858±1210^a	100^a
	1993	52	352±186^b	1660±1032^b	96^a
	2003	36	246±132^c	652±410^c	83^a
Southern	1981	39	340±201^a	2240±1151^a	97^a
	1992^#	63	220±123^b	1416±987^b	94^a
	2002	26	183±0.81^c	678±421^c	82^a
	2004	29	117±0.31^c	625±411^c	69^b
	1993	38	272±110^a	904±538^a	79^a
Southeastern	2003	14	151±43^b	476±206^b	53^b

CMIC - concentration completely inhibiting parasite maturation.

Values followed by a different letter in the same column within each study site were statistically different at P = 0.05 level.