Trypanosoma Gambiense Life Cycle

Trypanosoma gambiense is a protozoan hemoflagellate that causes a form of trypanosomiasis, an infectious disease of humans. Because of the specific neurological symptoms of the disease, it is more commonly known as west African sleeping sickness. In sleeping sickness, the parasites enter into the central nervous system, causing headaches, abnormal behavior, loss of consciousness and coma. All stages of African trypanosomiasis occur in extracellular fluids.

Human--Initial Infection

• An infected tsetse fly will bite a mammalian host. During the bite, the parasites, in the form of metacyclic trypomastigotes, infect the skin of the host. The parasites then travel to the lymphatic system. They eventually pass into the bloodstream.

Human--Reproduction

• Metacyclic trypomastigotes then transform into trypomastigotes, which are then carried to other parts of the body. The trypomastigotes enter into other fluids, such as lymph and spinal fluid, and continue the replication process by binary fission.

Tsetse Fly--Initial Infection

• Tsetse flies acquire the disease when they bite an infected host. The blood they consume contains the parasites, which transform into procyclic trypomastigotes in the fly's midgut, where they multiply by binary fission.

Tsetse Fly--Vector

• Eventually, they leave the midgut and transform into epimastigotes. The epimastigotes then migrate to the fly's salivary glands. At that point, they continue reproducing through binary fission. The tsetse fly then bites a host and infects it, starting the life cycle again.

Diagnosis and Treatment

• Examination of lymph, blood, bone marrow, cerebrospinal fluid and other bodily fluids for trypomastigotes is required for diagnosis. Once a diagnosis is confirmed, treatment should begin immediately. The drug of choice for west African sleeping sickness is pentamidine isethionate.