Breakdown of blood brain barrier in mice infected with P. berghei ANKA or co-infected with T. cruzi. C57BL/6 mice were separated in 4 groups, two of which were inoculated with T. cruzi G strain. Fifteen days later, one uninfected (n = 5) and one T. cruzi-infected group (n = 5) were inoculated with P. berghei ANKA, whereas one group remained uninfected (n = 3). When P. berghei-infected mice showed signs of neurological disorder, they were given the Evans blue and 1 h later the brain was removed. At this time, the corresponding number of mice in other groups received the dye and the brain was collected 1 h later. Note the difference of brain color in the three groups. The brains of the group with single T. cruzi infection (n = 5) (not shown) were indistinguishable from the normal mice.