1. Trypanosomiasis Sleeping Sickness David Humber Department of Life Sciences University of East London

2. Trypanosomes of Vertebrates T.corvi Corvids T.cruzi Humans, rodents, marsupials T.brucei spMan, ungulates T.lewisiRodents T.musculisRodents T.microtiVoles T.dionisiiBats T.equiperdum Equids Bone Marrow Heart muscle, autonomic ganglia Blood Lymphoid tissue Heart muscle Genitals SpeciesHostSite

3. African Sleeping Sickness Ngana South American Sleeping Sickness Chagas Disease

4. African Sleeping Sickness b Parasite - Trypanosoma brucei ssp Trypanosoma brucei rhodesienseTrypanosoma brucei rhodesiense Trypanosoma brucei gambienseTrypanosoma brucei gambiense b Vector - Tse Tse fly Glossina mortisans (Eastern Africa)Glossina mortisans (Eastern Africa) Glossina palpalis (Western Africa)Glossina palpalis (Western Africa)

5. Learning Outcomes b The Parasite & Vector b The Life Cycle b Clinical Features b Diagnosis b Epidemiology b Chemotherapy & Control b Vaccination

6. Taxonomy b Phylum b Sub-Phylum b Class b Order b Genus Mastigophora Sarcomastigophora Zoomastigophora Kinetoplastidae Trypanosoma ? species of mammals, birds, reptiles and amphibians

7. The Parasite b Polymorphic spindle-shaped Proliferative long-slenderProliferative long-slender IntermediatesIntermediates Non-proloiferative short-stumpyNon-proloiferative short-stumpy b Kinetoplast b Flagella & undulating membrane Trypomastigote Procyclic Epimastigote Parasitemia

13. African Trypanosomiasis The Life Cycle HumanTse fly TrypomastigoteTrypomastigote StumpyMetacyclic IntermediateEpimastigote SlenderTrypomastigote

14. The Vectors Glossina 22 species - hatchet wing cell Shady habitat (20-30 o C) Viviparous - 12 offspring Diurnal feeders (1mg/sec) Parasite development 10-14 days

17. Animal Reservoirs Sub species now thought to be zoonotic Largely ungulates Cattle & Pigs Wild game Hyaena

19. African Sleeping Sickness b Virulence b Reservoir b Zoonotic b Vector b Distribution Less More Human/animal Less More G.palpalis G.mortisans Western Africa Eastern Africa T.b.gambiense T.b.rhodesiense

20. Clinical Features Primary chancre - resolves 2-3 weeks Initial symptoms - fever & headaches Day time sleeping Tremors & Convulsions Coma & Death Enlarged cervical lymph nodes (T.b.g) Winterbottoms sign

25. Diagnosis b Direct microscopy Blood (T.b.r.)Blood (T.b.r.) Lymph node aspirate (T.b.g.)Lymph node aspirate (T.b.g.) Lumbar puncture (Late T.b.r. & T.b.g.)Lumbar puncture (Late T.b.r. & T.b.g.) b Serology b Animal inoculation

31. Epidemiology 50 million at risk <20% under surveillance 20,000 new case/year Devastating epidemics 200 endemic foci

32. Distribution of Disease & Vector

33. Chemotherapy b Early stage - most recover SuraminSuramin MelasporolMelasporol PentamidinePentamidine b Late stage - upto 5% relapse Only Melasoprol & EflornithineOnly Melasoprol & Eflornithine –10% encephalitis - 5% fatal

34. Control Destruction of animal reservoir Vector Control Diagnosis & treatment

37. Parasitemia

38. Variable Surface Glycoprotein 60kd (450aa) glycoprotein (CHO 7-17%) C-terminal anchored in membrane Often as a dimer (alpha helix) Densely clustered 10 7 molecules/parasite Only epitopes in end third of N-terminal exposed Presented as topographical array T-independent antigen

39. VSG Constant & Variable regions Random rearrangement of N terminal end (2/3) Almost no homology between V VSG’s Except cystein residues S-S bonds Switching not initiated by IR But selected

40. Production of VSG Gene rearrangement Produces on expression linked copy (ELC) ELC transposed to telomeric end of chromosome - replacing existing gene Displaced gene lost Switch occurs every 10 6 divisions 100-1000 copie of different VSG’s in clone

41. VSG Specific IR 3-4 days post infection strong IgM response Trypanosome disappear within hours VSG specific IgG appears - not relevant IgM response often >IgG After several cycles VSG abs vanish But abs to invariant ags remain elevated

42. Trypanosome Elimination Antibody mediated Destruction by Kupffer cells Splenic macrophages minor role (cf malaria) Uptake - C3b - C3bi - direct? C mediated lysis not important Trypanosome destroyed within minutes

43. Immunoregulation No secondary response to VSG’s unless cured by chemotherapy Failure of 1ry or 2ndry response prior to death Non specific polyclonal activation Suppresser Macrophages Failure of Ag presentation Anti idiotype responses

44. Resistance and Virulence Spectrum of disease T. brucei sub species Host differences Independant of VSG

45. Vaccination Effective Antibody response Phagocytosis & killing but Cyclical parasitemia Antigenic variation not predicable