In a paper recently published by PLOS Pathogens, Niko Heddergott and colleagues describe how they modeled the remarkable motion of the parasite Trypanosoma brucei, the African Trypanosome. The name “trypanosome” is derived from the Greek trypano (borer) and soma (body) because of the corkscrew-like motion that they make. African Trypanosomes are parasites that live free in the bloodstream and cause the deadly tropical disease known as African Sleeping Sickness in humans.
For propulsion, trypanosomes utilize a single flagellum, which follows the cell body and protrudes from the front end of the cell.
Continuous swimming by trypanosomes helps them to remove antibodies produced by the host’s immune system and deposited on their surface coat and tag them for destruction by macrophages (see article here). Yet blood is a crowded mixture of cells and other particles that might be expected to impede rapid swimming.
Niko Heddergott and colleagues show that trypanosomes actually swim much more quickly among particles than in particle-free environments, and, using modeling, demonstrate that they swim near their maximum speed among particles of similar properties to red blood cells.
The article has more videos of African Trypanosomes. It also explains how trypanosomes remove antibodies by swimming, how researchers simulated the conditions in the bloodstream and how they described trypanosome motion with computer simulation.