Table 2.

Distribution by age of 76 infants congenitally infected with Trypanosoma cruzi analyzed by PCR with species-specific primers

Age, months	Total	No. (%) T. cruzi positive by PCR*	Intensity of PCR products by primers TCZ 1–TCZ 2†			No. PCR positive by primers 121–122‡
			Weak	Average	Strong
0–12	45	37 (82)	0	17	18	2
13–24	14	10 (71)	1	4	4	1
25–36	6	4 (67)	0	3	1	0
37–48	6	4 (67)	0	1	2	1
49–60	5	3 (60)	0	3	0	0
Total	76	58 (100)	1	28	25	4

^*T. cruzi-positive samples identified by using species-specific primers TCZ 1–TCZ 2 and 121–122.

^†Intensity of PCR products observed by 2% agarose gel electrophoresis and staining with ethidium bromide.

^‡T. cruzi DNA was detected in these samples with primers 121–122; they were not detectable with primers TCZ 1–TCZ 2 primers.