African Trypanosomaisis

 Nagana: -Zulu “To be depressed”  First described in the 14 th century  Noticed by slave traders who would not buy slaves displaying symptoms  Trypanosomes first detected in humansin

 Worked in Ubombo, South Africa with wife Mary  Discovered both trypanosome and transmission by tsetse fly in 1903  ‘trypanosome fever’ = ‘sleeping sickness’

 Bites of Tsetse flies, vertical, or mechanical transmission  Earliest epidemic took place between 1896 and 1906; estimated 800,000 died.  Major break outs in 1940’s and 1980’s; smaller epidemics from Senegal to Cameroon from ’s.  Linked to droughts and political turmoil due to increase human-fly contact

Glossina/Tsetse flies

T. brucei gambiense  West African Sleeping Sickness  Chronic, moderate symptoms with delayed onset  Represent more than 90% of sleeping sickness cases T. brucei rhodensiense  East African Sleeping Sickness  Rapid onset of severe symptoms  Intermittent fever within a few weeks

 Shifts from procyclic to metacyclic to trypomastigotes after exposure  Reproduction occurs through binary fission  Highly aerobic and completely dependent on host glucose for energy  Variant Surface Glycoprotein (VSG) are used to evade antibodies ◦ shields parasitic surface proteins and transport channels ◦ capable of shifting gene expression

 Early/hemolytic stage ◦ Bouts of fever, headaches, joint pain and itching ◦ Caused by hemolysis due to IgM-antigen complex which binds to ethryocytes  Late/CNS stage ◦ T. b. rhodensiense may advance within a few weeks while T. b. gambiense may take decades ◦ Begins as the parasite crosses the blood-brain barrier resulting in confusion, sensory disturbances, poor coordination, and sleep cycle disturbances

 Stage dependent ◦ Stage 1: Pentamidine and suramin (few side effects ◦ Stage 2: Melarsoprol – works against both strains but has severe side effects ◦ Eflornithine – Only works against T. b. gambiense but is much less toxic than melarsoprol.  Difficult to apply and requires strict regiment  -New Drugs on horizon

 On the Neglected Tropical Disease list  2000 – WHO partners with Aventis Pharma to provide treatment and free medicine to endemic countries  2006 – Success of WHO program causes increased private partners to assist in reducing African Trypanosomiasis as a health concern ◦ Still have limited surveillance and diagnostic abilities

 Insecticides  Bush clearing ◦ Harmful to environment  Game animal killing  Sterile male techniques ◦ Female only mates once  Pheromone-baiting traps ◦ Effective, cheap, nonpolluting, and trusted

 Screening: Use clinical signs and/or serological assays to find at-risk individuals  Diagnose  Determine stage: Examine cerebral-spinal fluid for parasites o T. b. gambiense requires active and exhaustive screening necessary in at-risk areas o “No universal methodology”

 3 million cattle die per year; over 35 million doses of trypancidal drugs administered  Under list B of the World Organization for Animal Health (OIE) ◦ High socio-economic or health importance in countries that are significant in international trade  Most economically important livestock disease ◦ loss of ~1 billion per year mages/hl_06.jpg

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