Development of Trypanosoma cruzi in the vector in the absence of blood.

First stage nymphs of Triatoma infestans and Dipetalogaster maximus which had never fed after egg hatching, were allowed to ingest by artificial feeding a blood-free suspension of Trypanosoma cruzi trypomastigotes collected from experimentally infected mice. A high percentage of the vectors acquired a normal infection and produced infective stages. The parasite's development in the vector did not require blood but may have needed the presence of unknown factors secreted and/or excreted in the insect's digestive tract.