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Sleeping sickness

By Levi Clancy for Student Reader on

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Various trypanosomes are associated with sleeping sickness, also known African trypanosomiasis.

This is in contradistinction to American trypanosomiasis which is distributed only in central and south America.

Trypanosoma rangeli

AgentTrypanosoma rangeli is a protozoan parasite morphologically similar to T. cruzi and with an overlapping geographical distribution. T. rangeli infects humans and other animals but does not have pathogenic activity. However it is devastating to its insect vector R. prolixus.
VectorTransmitted by the Reduviid (aka kissing bug) genera Rhodnius prolixus which resides in rural settings or forests.
TransmissionRhodnius prolixus discharges Trypanosoma rengali via its saliva whilst taking a blood meal.

Trypanosoma evansi

Surra DiseaseIn 1880, Griffith Evans, an English veterinarian in Punjab, India, found trypanosomes in the blood of horses, mules and camels suffering from a fatal wasting disease called surra (aka African Trypanosomiasis today). Inoculating healthy animals with trypanosome-infected blood produced surra; Evans was convinced the trypanosome was a parasite. In 1899, another research identified a biting stable fly as the vector. The trypanosome was later known as Trypanosoma evansi.

Trypanosoma sanguinis

First SightingsIn 1841, G. Valentinin Berne of Switzerland examined trout blood and saw a protozoan propelled by an undulating membrane. This was a trypanosome. In 1843, David Gruby of Paris discovered a similar organism in frog blood and called it Trypanosoma sanguinis. Its etymology is: the Greek word trypano, meaning auger- or screw-like; the Greek word soma, meaning body; and the Latin word sanguinis, meaning blood. Trypanosomes were considered curiosities with no applied importance.

Trypanosoma brucei

Trypanosome brucei includes three subspecies.