Table 1.

Parasitaemia, mortality rate and myocarditis in mice acutely infected with T. cruzi

Variables	BALB/c	C57BL/6
Parasitaemia¶
Day 7 p.i.	12 (8–22)	13 (1–22)
Day 14 p.i.	43 (22–55)	42 (4–61)
Day 21 p.i.	470 (210–650)	291 (111–691)
Mortality rate†	13/32	26/27§
Mean survival time‡	26·3 ± 0·7	23·4 ± 0·3*
Parasite nests/heart**	2·2 ± 1·1	1·2 ± 0·3
Number of inflammatory foci***	11·5 ± 3·1	4·7 ± 1·5

Heart samples were obtained on day 14 p.i., and fixed in buffered formalin, whereas paraffin-embedded 5 μm sections were stained with haematoxylin-eosin.

^¶Values represent median (rank) of parasites/50 fields of five mice/group (one representative of three independent experiments).

^†Mice dead/total mice.

^‡Mean ± standard error of the mean (s.e.m.), days;

^**and

^***indicate total numbers of parasite nests and inflammatory lesions detected in the three serial sections, respectively. Values represent the mean ± s.e.m. of 8–10 mice/group (one of two independent experiments).

^§P < 0·003.

^*P < 0·01.