Triatoma dimidiata feces naturally contaminated with Trypanosoma cruzi :
Inflammatory response at the inoculation site
Abstract
Aim: Natural transmission of Trypanosoma cruzi occurs when
infected hematophagous deposit feces contaminated with metacyclic
trypomastigotes on injured skin or mucosa. To study the inflammatory
response at the inoculation site, dissemination of parasites, Th cell
subtypes at the local lymph nodes and myocarditis mice were exposed to
Triatoma dimidiata naturally contaminated with Trypanosoma
cruzi. Methods and results: Mice were intradermal inoculated
with T. dimidiata feces containing metacyclic trypomastigotes or
were previously immunized with feces without metacyclic trypomastigotes
and analyzed from 15 minutes to 3 months after inoculation. Parasites
remained at the inoculation site until 20 days after inoculation but
disappeared early in pre-immunized mice that presented with edema and
collagen fragmentation as early as 15 minutes after being challenged
with metacyclic trypomastigotes. The Th2 subpopulation dominated in the
first week in mice infected with feces containing metacyclic
trypomastigotes, whereas Th1 and Th17 populations dominated in the
challenged mice population. Similarly in heart tissue, intense
myocarditis and remodeling, with faster clearance of amastigotes was
observed in mice previously immunized with Triatoma dimidiata
feces. Furthermore, immune cell-types, Th1 and Th17, predominated after
20 days post-infection in all experimental groups. Conclusions: Previous
exposure with Triatoma dimidiata feces prior to infection with
metacyclic trypomastigotes favors parasitic dissemination and early
induction of Th1 and Th17 subpopulations with lower parasitism in heart
tissue but does not ameliorate inflammation and tissue damage which is
accompanied with Th1/Th17 and Treg profile.