Serum neuraminidase activity and hematological alterations in acute human Chagas' disease.

Neuraminidase activity was detected in serum 12 days after an accidental laboratory infection with Trypanosoma cruzi, peaked at the time when clinical symptoms appeared, and dropped to undetectable values by the day antibodies specific for T. cruzi were first demonstrated. A seric factor blocking neuraminidase activity was demonstrated when antibodies were first detected and persisted with high titers for at least 12 weeks thereafter. Erythrocyte and white blood cell counts as well as hemoglobin and hematocrit were below the lower limit of normality when seric neuraminidase activity was at its peak.