Orally Acquired Chagas Disease in Rats Exposed to Naturally Infected Triatominae Bugs

Area of Science:

• Parasitology
• Infectious Diseases
• Military Health

Background:

• Chagas disease (American Trypanosomiasis) is transmitted by infected kissing bugs (Triatominae).
• Military personnel deployed in endemic areas face risks of infection through contact with infected bug feces, blood transfusions, or insect ingestion.
• The precise infection routes for military personnel and working dogs remain unclear.

Purpose of the Study:

• To evaluate various oral exposure routes for Trypanosoma cruzi infection in a rat model.
• To determine the infection rates and antibody development following different exposure methods.

Main Methods:

• Rats were exposed orally to Trypanosoma cruzi via infected insect excreta, digestive tract, mucosal scraping, or whole infected bugs.
• Infection was monitored for 12 weeks using indirect immunofluorescent assays for IgM and IgG antibodies.
• Histopathological analysis of heart, spleen, kidney, and stomach was performed at necropsy.

Main Results:

• All tested oral exposure routes successfully established Trypanosoma cruzi infection in rats, leading to antibody development.
• Ingestion of whole insects or oral mucosa resulted in high IgM responses by 14 days post-infection (86% and 100%).
• Significant IgG responses were observed in 85.7% of orally exposed rats by 35 days post-infection.

Conclusions:

• Various oral exposure routes effectively transmit Trypanosoma cruzi infection in a laboratory setting.
• The study suggests higher infection rates than previously reported, potentially reflecting natural transmission dynamics.
• Further research is needed to explore host susceptibility and specific exposure vehicles.