Sub genus : Schizotrypanum

Trypanosoma cruzi

Location and host

• These parasites are found in blood of man, dog, cat, etc. Reduviid bugs are vectors

Morphology

• These are monomorphic trypanosomes, 16-20 µm long.
• They have pointed posterior end and curved stumpy body.
• Undulating membrane is narrow with trailing flagellum.
• Kinetoplast large and sub-terminal, causing the body is bulge around it.
• Amastigotes are 1.5-4 µm in diameter and occur in groups.

Life cycle

• Trypomastigote forms enter cells of reticuloendothelial system, muscles and especially in heart.
• Trypanomastigote there changes into rounded amastigotes.
• Amastigotes multiply by binary fission forming group of parasites, that turn inti trypomastigote forms which re-enter blood.
• Vectors take these forms and once ingested , trypomastigotes pass to mid gut. There they turn into amastigote forms.
• They multiply by binary fission and turn into either metacyclic trypomastigote or epimastigote forms.
• Epimastigote further multiplies and extend into the rectum, where they turn into metacyclic trypomastigote. These forms are passed out in faeces.

Transmission

• Through bite of kissing bugs (Reduviidae)

Pathogenesis

• Trypomastigotes forms are found in blood, and amastigote forms are found in pseudocyst in skeletal and cardiac muscle, reticuloendothelial system and other tissues.
• Disease caused by this parasite is ‘chayas disease’.
• Infection occurs generalized edema, anemia, hepatosplenomegaly and lymphadenitis.

Clinical signs

• Depression
• Anorexia
• Weight loss

Diagnosis

• Trypomastigotes can be found in thick blood smears stained with Giemsa.
• CFT or ELISA for humans and helpful in screening.

Treatment and control

• NO effective treatment
• Elimination of insect vectors