By Levi Clancy for Student Reader on
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.
|Agent||Trypanosoma 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.|
|Vector||Transmitted by the Reduviid (aka kissing bug) genera Rhodnius prolixus which resides in rural settings or forests.|
|Transmission||Rhodnius prolixus discharges Trypanosoma rengali via its saliva whilst taking a blood meal.|
|Surra Disease||In 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.|
|First Sightings||In 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.|
Trypanosome brucei includes three subspecies.