Trypanosoma brucei gambiense and rhodesiense Profile 3 subspecies

Trypanosoma brucei gambiense and rhodesiense

Profile § 3 subspecies- brucei, gambiense, rhodesiense § Causes trypanosomaiasis (African sleeping sickness) § 2 hosts- 1 insect, 1 mammalian § Lives in bloodstream § Classification: kingdom- Protista phylumclassordergenusspecies- Euglenozoa Kinetoplastea Trypanosomatida Trypansoma T. brucei

gambiense vs. rhodesiense § Gambiense- causes slow onset chronic trypanosomaiasis, infects only humans (West African Sleeping Sickness) , transmitted human to human via a vector § Rhodesiense- causes fast onset acute trypanosomaiasis, infects animals (East African Sleeping Sickness), able to be transmitted to humans

Incidence Gambiense Rhodesiense

Life Cycle Procyclic cells replicate in fly’s midgut Transform into epimastigotes, replicate Transform into metacyclic trypomastigotes in salivary gland

Life Cycle Tsetse fly Metacyclic Trypomastigote Bloodstream

Life Cycle Bloodstream trypomastigote Binary fission replication in blood Tsetse fly takes blood meal

First Stage of Disease § West (Gambiense)- fever, faint rash § East (Rhodesiense)- possible death without treatment

Second Stage of Disease § West- after months § East- after weeks : § Trypanosomes cross blood-brain barrier, enter central nervous system

Second Stage (con’t) § encephalopathy –brain disease

Second Stage (con’t) § § § Reduced mental functions Difficulty in concentration Eventually enter terminal somnolent state, “Sleeping Sickness”

Death § After considerable loss of weight, most patients die § West- after months, East- after weeks

Treatment for West (Gambiense) § Stage 1 -first line: pentamadine -second line: eflornithine or melarsoprol § Stage 2 -first line: melarsoprol -second line: eflornithine

Treatment for East (Rhodesiense) § Stage 1 -first line: suramin -second line: melarsoprol § Stage 2 -first line: melarsoprol -second line: nifurtimox combined with melarsoprol

Problems with Treatment § Many drugs cause extensive brain damage § Hard to obtain drugs in certain regions of Africa § Treatment, resources scarce in poor areas