The development of extra-intestinal cycle of Trypanosoma cruzi in Triatoma infestans and Panstrongylus megistus.

By applying various histological techniques the results obtained were similar to those in Lacombe's previous publications referring to the development of Trypanosoma cruzi in haemolymph, the later penetration in the Malpighian tubes and their return to the digestive tract. Trypomastigotes and sphaeromastigotes are found in the promesenteron after two hours of feeding the insect with mice blood containing numerous Trypanosoma cruzi. Some parasites move to the promesenteron from postmesenteron and others from the haemolymph of the insect. The amastigotes form inside the haemocytes, multiply, occupying nearly all the cells of the haemolymph. The parasites liberated inside the Malpighian tubes move to the ampullae where they begin their growth. The parasites in epimastigote and trypomastigote forms cross the pyloric valve and adhere to the folds of the rectum.