A Paratransgenic Strategy for the Control of Chagas Disease

Figure 2

An infected triatomine bug takes a blood meal and releases trypomastigotes in its feces near the site of the bite wound. Trypomastigotes enter the host through the wound (1). Inside the host, the trypomastigotes invade cells near the site of inoculation, where they differentiate into intracellular amastigotes (2). The amastigotes multiply by binary fission and form pseudocysts (3). Following several cycles of division, these cells will asynchronously differentiate into trypomastigotes, which are then released into the circulation as bloodstream trypomastigotes where they can start infecting cells from other tissues (4). The cycle of infection continues as another triatomine bug becomes infected by feeding on human blood containing the circulating parasites (5). The ingested trypomastigotes transform into epimastigotes in the vector’s midgut (6). The parasites multiply in the midgut (7) and differentiate into infective metacyclic trypomastigotes in the hindgut (8). This figure is adapted from http://www.dpd.cdc.gov/dpdx.