A method has been developed for isolating Trypanosoma cruzi from the blood of infected animals by inoculation into monolayers of a cell line (DC2) derived from a murine chondrosarcoma. The isolation rate and the time needed to detect the parasites by this method were compared with results obtained by inoculation into NNN medium and by the intracerebral inoculation of mice. Blood from mice experimentally infected with T. cruzi during the acute and chronic phases was withdrawn aseptically, the plasma centrifuged, and the sediment resuspended in phosphate-buffered saline solution for inoculation into NNN medium, newborn mice intracerebrally, and tissue culture. Parasite isolation rates for the eight acutely infected mice were similar with all three methods. However, parasites were found with a mean interval of 5 days after inoculation into tissue culture, whereas the average time needed with NNN medium was 10 days and isolation in mice was 12 days. Parasites from the 30 chronically infected mice were found in the 30 instances when blood was inoculated into tissue culture, but only in 28 instances in NNN and in mice. The average time interval required for isolation in tissue culture was 11 days, in mice 15 days, and in NNN 20 days. The ease of isolating T. cruzi from blood in tissue culture offers advantages when parasites are scanty, since it permits their demonstration in shorter periods of time. The method could be useful for the rapid differentiation of T. cruzi from Trypanosoma rangeli.
The Puerto Rico Nuclear Center is operated by the University of Puerto Rico under Contract AT-(40-1)-1833 for the U.S. Atomic Energy Commission.