Read this article to learn about the Structure and Life Cycle of Trypanosome !
Systematic Position
Phylum: Euglenozoa
Class: Kinetoplastida
Order: Trypanosomatida
Genus: Trypanosoma
Species: cruzi
Trypanosome is a flagellate pathogenic parasite growing in man and domestic animals causing fatal diseases known as Trypanosomiasis.
Trypanosome has clourless, elongated and flattened leaf like body. It is spindle shaped about 10 to 40 long and 1 to 5 broad.
A firm but elastic pellicle, supported by fine microtubules covers the body and maintain its shape. A long thread like flagellum project from the front end of the body.
All along its length over the body, the flagellum is connected by a fin-like undulating membrane formed of cytoplasm and folded pellicle (Fig. 9.22). There is a large oval nucleus and a long oval narrow band like mitochondrion in the cytoplasm. A conspicuous mass of DNA called Kinetoplast is embedded in the mitochondrion near the gullet.
In between the reservoir and the nucleus, Golgi apparatus is found. In trypanosomes large deeply-staining volutin granules are found scattered in the cytoplasm. These granules represent the stored glycogen or protein or nucleic acids. Endoplasmic reticulum with ribosome’s is also present.
Life Cycle:
The life cycle of most trypanosomes species is digenetic. Man and domestic animals serve as primary host and blood-sucking insect, the tsetse fly serve as the intermediate host (fig. 9.23). Man and domestic animals becomes infected by the bite of tsetse fly. The injected parasite undergo prepatent period of active multiplication in lymph, intercellular spaces and tissue cells. Finally the parasite invades blood. It undergoes extensive multiplication.
During multiplication it changes shape of its body several times but finally changes into normal trypanosomes. At this stage, it is ready for transmission into the intermediate host. After sometime the pararits disappear completely from the blood due to formation of antibodies in host body. In pathogenic forms, the parasites invade vital organs from the blood causing serious disease.
In invertebrate host also, the parasite undergo extensive multiplication in stomach. Ultimately they migrate into salivary glands. When tsetse fly bites the skin of vertebrate host for its blood- meal, if pours a drop of saliva into the wound to prevent blood coagulation. With the drop of saliva numerous trypanosomes are inoculated into the blood of final host.