Trypanosoma brucei

Trypanosoma brucei
"Trypanosoma brucei brucei" TREU667 (Bloodstream form, phase-contrast picture. Black bar indicates 10 µm.)
T. b. brucei TREU667 (Bloodstream form, phase-contrast picture. Black bar indicates 10 µm.)
Scientific classification Edit this classification
Domain: Eukaryota
Phylum: Euglenozoa
Class: Kinetoplastea
Order: Trypanosomatida
Family: Trypanosomatidae
Genus: Trypanosoma
Species:
T. brucei
Binomial name
Trypanosoma brucei
Plimmer & Bradford, 1899
Subspecies
  • Trypanosoma brucei brucei
  • Trypanosoma brucei gambiense
  • Trypanosoma brucei rhodesiense

Trypanosoma brucei is a species of parasitic kinetoplastid belonging to the genus Trypanosoma that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is exclusively extracellular and inhabits the blood plasma and body fluids.[1] It causes deadly vector-borne diseases: African trypanosomiasis or sleeping sickness in humans, and animal trypanosomiasis or nagana in cattle and horses.[2] It is a species complex grouped into three subspecies: T. b. brucei, T. b. gambiense and T. b. rhodesiense.[3] The first is a parasite of non-human mammals and causes nagana, while the latter two are zoonotic infecting both humans and animals and cause African trypanosomiasis.

T. brucei is transmitted between mammal hosts by an insect vector belonging to different species of tsetse fly (Glossina). Transmission occurs by biting during the insect's blood meal. The parasites undergo complex morphological changes as they move between insect and mammal over the course of their life cycle. The mammalian bloodstream forms are notable for their cell surface proteins, variant surface glycoproteins, which undergo remarkable antigenic variation, enabling persistent evasion of host adaptive immunity leading to chronic infection. T. brucei is one of only a few pathogens known to cross the blood brain barrier.[4] There is an urgent need for the development of new drug therapies, as current treatments can have severe side effects and can prove fatal to the patient.[5]

Whilst not historically regarded as T. brucei subspecies due to their different means of transmission, clinical presentation, and loss of kinetoplast DNA, genetic analyses reveal that T. equiperdum and T. evansi are evolved from parasites very similar to T. b. brucei, and are thought to be members of the brucei clade.[6]

The parasite was discovered in 1894 by Sir David Bruce, after whom the scientific name was given in 1899.[7][8]

  1. ^ Romero-Meza, Gabriela; Mugnier, Monica R. (2020). "Trypanosoma brucei". Trends in Parasitology. 36 (6): 571–572. doi:10.1016/j.pt.2019.10.007. PMC 7375462. PMID 31757771.
  2. ^ Luzak V, López-Escobar L, Siegel TN, Figueiredo LM (October 2021). "Cell-to-Cell Heterogeneity in Trypanosomes". Annual Review of Microbiology. 75 (1). Annual Reviews: 107–128. doi:10.1146/annurev-micro-040821-012953. PMID 34228491. S2CID 235759288.
  3. ^ Baker JR (March 1995). "The subspecific taxonomy of Trypanosoma brucei". Parasite. 2 (1): 3–12. doi:10.1051/parasite/1995021003. PMID 9137639. Open access icon
  4. ^ Masocha W, Kristensson K (2012). "Passage of parasites across the blood-brain barrier". Virulence. 3 (2): 202–212. doi:10.4161/viru.19178. PMC 3396699. PMID 22460639.
  5. ^ Legros D, Ollivier G, Gastellu-Etchegorry M, Paquet C, Burri C, Jannin J, Büscher P (July 2002). "Treatment of human African trypanosomiasis--present situation and needs for research and development". The Lancet. Infectious Diseases. 2 (7): 437–440. doi:10.1016/S1473-3099(02)00321-3. hdl:10144/18268. PMID 12127356.
  6. ^ Gibson W (July 2007). "Resolution of the species problem in African trypanosomes". International Journal for Parasitology. 37 (8–9): 829–838. doi:10.1016/j.ijpara.2007.03.002. PMID 17451719.
  7. ^ Joubert JJ, Schutte CH, Irons DJ, Fripp PJ (1993). "Ubombo and the site of David Bruce's discovery of Trypanosoma brucei". Transactions of the Royal Society of Tropical Medicine and Hygiene. 87 (4): 494–495. doi:10.1016/0035-9203(93)90056-v. PMID 8249096.
  8. ^ Cook GC (1994). "Sir David Bruce's elucidation of the aetiology of nagana--exactly one hundred years ago". Transactions of the Royal Society of Tropical Medicine and Hygiene. 88 (3): 257–258. doi:10.1016/0035-9203(94)90068-x. PMID 7974656.