Chagas Disease: Parasitemia Identified via Serial Hemoculture in Blood Donor Candidates Infected with Trypanosoma cruzi

The chronic phase of individuals infected with Trypanosoma cruzi is characterized by low parasitemia. Blood donors in endemic and some nonendemic countries are screened for antibodies against the parasite. Data on the parasitemia of individuals identified via serological tests, as well as the risk of transfusion transmission if the screening process fails to detect infected individuals, are scarce. The potential of culturing parasites during the chronic phase increases if blood collections are performed at least three times. Sequential hemoculture (three blood collections over 3 consecutive months) was performed in 26 blood donor candidates identified as infected using serology screening and in 23 infected individuals from outpatient clinics. Each blood sample was aliquoted into six tubes for culture. At least one culture yielded a positive result in 16 of 26 (61.5%) blood donors and in 13 of 23 (56.5%) of infected controls, resulting in an overall positivity rate of 29 of 49 (59.2%). There was a relationship between the positivity of cultures and the number of positive tubes. All type B blood donors (n = 6) had positive hemoculture results, whereas only half of the type A and O donors had positive results (n = 10; P = 0.02). The number of positive tubes was also higher in this group. The implications of this finding are unclear. The analysis revealed no relationship between antibody concentration levels and the presence of positive hemoculture results. In conclusion, more than half of the infected blood donors could potentially transmit T. cruzi to recipients. This highlights the importance of blood donor screening programs for Chagas disease, even in nonendemic regions.