Table I.

Seroprevalence of Anti–TSSA-I and Anti–TSSA-II Abs in Populations from Distinct Geographical Origins

						Percentage of reactive sera
Origin	Serum panel	n	Conventional serology (IHA, IFI, ELISA) reactivity (%)	EpEx CL-ELISAareactivity (%)	Hemoculture	Anti–TSSA-Ib	Anti–TSSA-II
Argentina	Chagasic	66	100	ND	ND	3.0	95.4
	Non-Chagasic	10	0	ND	ND	0	0
Brazil	Chagasicc	112	100	98.2	ND	5.4	82.1
	Chagasicd	48	100	100	+	0	100
	Chagasice	75	100	100	+	2.7	100
	Non-Chagasic	126	0	0	ND	0	0
Chile	Chagasicc	23	NDf	100	ND	8.7	87.0

Sera were grouped according to the country of origin and diagnosis criteria and tested at 1:200 dilution for TSSA-I and TSSA-II reactivity by ELISA (Argentinean samples) and/or CL-ELISA (Brazilian and Chilean samples).

^aEpEx CL-ELISA, chemiluminescent ELISA test using an epimastigote (Tulahuén strain) preparation as antigen (reference 25).

^bPositive sera showed very low reactivity against TSSA-I, with reading (absorbance or relative luminescent unit) values close to the cutoff value for the specific test. Sera reactive for TSSA-I were also positive for TSSA-II, with reading values for the latter higher than those observed for the former (see also Fig. 6 C).

^cPotentially Chagasic patients.

^dConfirmed Chagasic patients.

^eConfirmed Chagasic patients coinfected with HIV.

^fND, not determined.