TRYPANOSOMA-CRUZI IN THE RECTUM OF THE BUG TRIATOMA-INFESTANS - EFFECTS OF BLOOD INGESTION BY THE STARVED VECTOR

To follow the developmental effects of feeding of the insect host afte r long starvation periods, the population density and composition of a n established infection of Trypanosoma cruzi in the rectum of Triatoma infestans were determined 60 days after the last feeding (daf) and th en at different intervals after feeding. The original population decre ased and then increased up to the 10th daf. In starved bugs, about 30% were spheromastigotes (including intermediate forms), 20% epimastigot es, and 50% trypomastigotes, but one daf, these forms represented 2%, 70%, and 10%, respectively. In addition, one daf there were about 10% giant cells, i.e., a multiple division stage. in the following two day s, this form represented on average 30-50% of the total population, bu t it then disappeared nearly completely. Thus, giant cells evidently d evelop by rapid growth of epimastigotes, if conditions become optimal after long starvation periods of the vector.