Chagas disease is caused by which organism?

• A. Leishmania braziliensis
• B. Trypanosoma cruzi
• C. Dracunculus medinensis
• D. Trypanosoma brucei

Answer: (B)

Chagas disease is caused by a protozoan parasite, Trypanosoma cruzi. This organism is transmitted to humans mainly through triatomine bugs, or kissing bugs, which defecate near the bite site and allow the parasite to enter through the skin or mucous membranes. In the human host, the parasite has tissue stages (amastigotes) and bloodstream stages (trypomastigotes); acute infections can be mild or nonspecific, while chronic infection may lead to serious heart problems or gastrointestinal megastructures such as megacolon or megaesophagus. Diagnosis relies on detecting parasites in the blood during the acute phase or using serology/PCR for chronic infection. Treatments like benznidazole or nifurtimox target the parasite. The other organisms listed cause different diseases: Leishmania braziliensis causes leishmaniasis; Dracunculus medinensis causes Guinea worm disease; Trypanosoma brucei causes African sleeping sickness.