Onchocerca volvulus

1
Onchocerca volvulus

• David Meyer

2
Brief Review

• Helminthes worm
• Commonly called river blindness
• Blackfly vector

3
Life Cycle Quickie
4
Historical Accounts

• Microfilariae of a river blindness mentioned in
  ancient Egyptian text. 2nd millennium BC.
• Also mentioned in African account of river
  blindness in 1st millennium BC.

5
The Road to Discovery

• John ONeill in 1874 (microfilaria)
• I was induced to bestow much time on its
  microscopic examination, and succeeded length in
  discovering a filaria which I believe to be the
  immediate cause of the complaint.
• Unnamed German Doctor in 1890 (adult worm)
• Leuckart in 1890 (adult worm)
• Robles in 1917 (blackfly vector)
• Donald Blacklock in 1923 (transmission)

6
Cultural Practices

• Farming techniques in Africa (Nigeria)
• Living near open running water
• Cultural fishing practices
• Clothing options

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Human Migrations

• Migration of population after village becomes
  infected with Onchocerciasis
• Blackfly migration
• Bantu Expansion/Nomadic tribes
• Prevalence 35 countries total. 28 in tropical
  Africa where 99 of infected people live.
• 17.7 million infected

8
Infrastructure

• Lack of knowledge/education
• Location of communities close to blackfly
  breeding grounds
• Poor medical attention for those who are infected
• Agricultural/Cultural practices expose humans to
  vector

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Response of Health Care

• Treatments
• Ivermectin
• Albendazole
• Corticosteroids
• Control
• Using protective netting
• Pesticides

10
Anthropogenic Changes

• Deforestation
• Economic Development
• Education

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Resources

• www.dpd.cdc.gov
• www.who.int/tdr/diseases/oncho/
• www.emedicine.com/med/topic1667.htm
• ucdnema.ucdavis.edu/imagemap/nemmap/ent156html/nem
  as/onchocercavolvulus
• en.wikipedia.org/wiki/Onchocerciasis