The T. cruzi strains are a complex of multi-clonal populations that affects the brain with more severity in
children or young animals, suggesting that functional immaturity of the blood brain barrier (BBB) might be involved in T.
cruzi infection in the brain. This study investigated relationships between BBB permeability and T. cruzi infection in the
rat brain. The animals were inoculated with one of 3 strains of T. cruzi at 30 days of age, and BBB permeability was
increased by subcutaneous kainic acid injection in half of the infected animals. The animals were sacrificed at 13 days of
infection. The brain sections were stained with hematoxylin and eosin. The all brains of the infected animals with and
without kainic acid showed both glial nodules and perivascular infiltrates due to T. cruzi infection. Number of these glial
nodules was counted in each rat, and statistical comparison indicated that kainic acid-treatment significantly increased
mean numbers of glial nodules in all of the rats infected with the 3 strains. The results indicated that the increased BBB
permeability was one of the factors for facilitation of the entry of T. cruzi into the brain.