RIVER BLINDNESS

1
RIVER BLINDNESS
Kenetra Ruffin, MBA/HCM, BSMT, BB(ASCP) PhD
Candidate Public Health Epidemiology Walden
University PUBH 8165-3 Instructor Dr. Rebecca
Heick Fall 2009
2
Table of Contents

• What is River Blindness?
• Causative Agent
• Life Cycle of Onchocerca volvulus
• Signs Symptoms
• The Blindness
• The Rivers
• Geographical Distribution
• Morbidity/Mortality
• Prevention Control
• Help is Needed

3
What is River Blindness?

• The medical term is called Onchocerciasis.
• It is the worlds second leading cause of
  infectious blindness.
• It is caused by black flies that breed in fast
  flowing water that transmit the disease to people
  in riverside areas.
• It is a chronic condition that is rarely life
  threatening, but has extreme manifestations and
  causes severe disability for infected persons.
• 99 of infected people live in tropical areas of
  Africa.
• References World Health Organization
  WHO/Tropical Disease Research TDR, 2004

4
Causative Agent

• Is a parasitic nematode worm known as Onchocerca
  volvulus.
• The larvae from the worm is injected to a host
  once the person is bitten by an infected blackfly
  from the genus Simulium.
• The blackfly is the only vector of the parasite .

References Eezzuduemhoi Wilson, 2008 WHO/TDR,
2004
5
Life Cycle of Onchocerca volvulus
Reference University of Tuebingen, n.d.
6
Signs Symptoms

• Nodules
• Debilitating pruritus
• Malnutrition
• Stigmatizing skin lesions
• Depigmentation of the skin
• Skin rashes
• Intense itching
• Elephantiasis of the genitals
• Visual Impairment
• Blindness

References Goldbamboo, 2009 WHO/TDR, 2004
7
The Blindness

• There are approximately 2 million people who are
  blind because of the disease.
• The microfilariae of the parasite enters the eye
  of the host by passing along the sheaths of the
  vessels and nerves from under the conjunctiva
  directly into the cornea.
• Dead microfilariae in the eye leads to an
  inflammatory immune response, the formation of
  secondary cataracts and ocular lesions.
• The results of the heavy infections often lead to
  progressive blindness in the hosts.

References Goldbamboo, 2009 UC Davis, 2006
8
The Rivers

• Fast flowing rivers, streams and well oxygenated
  waters are where the blackfly breeds.
• The larvae of the parasite have an obligatory
  aquatic stage during which they require high
  oxygen tension.
• This is why Onchocerciasis is often referred to
  as river blindness.

References UC Davis, 2006 Department of Water
Affairs and Forestry, n.d.
9
Geographical Distribution

• Approximately 96 of all reported cases of River
  Blindness are in Africa.
• 30 of the 36 endemic countries that have the
  disease are in sub-Saharan Africa.

References UC Davis, 2006 Nations Online, 2009
10
Morbidity/Mortality

• About 85.5 million people live in the endemic
  areas.
• An estimated 18-40 million people are affected
  worldwide.
• Infection with O. volvulus reduces immunity and
  resistance to other diseases, and this results in
  a reduction of the life expectancy of infected
  individuals by almost 13 years.
• Reference Eezzuduemhoi Wilson, 2008

11
Prevention Control

• Ivermectin is an antimicofiliarial agent that
  provides primary prevention for endemic
  communities by decreasing the number of
  microfilariae picked up by blackflies during
  feedings.
• Ivermectin also acts as a secondary prevention
  method in infected individuals by reducing the
  parasite survival rate.
• No effective vaccine exists and ivermectin only
  kills the larvae, not the adult worms.
• The risk of resurgence remains and treatment
  programs must occur on annual basis.
• Reference Poolman Galvani, 2006

12
Help is still needed

• River blindness is a major public health problem
  that must addressed.
• Millions of people are still chronically
  suffering from the ill effects of the disease.
• The company who manufactures ivermectin has
  pledged to make a donation of the drug as long as
  it is needed.
• This is an important stimulus for the current
  initiative to globally control river blindness.
• Using community-based treatment strategies will
  continue to be helpful.
• You can help by supporting the various
  intervention efforts that are being conducted by
  the World Health Organization, the Carter Center
  and other organizations.
• Reference The Carter Center, 2009

13
References

• Centers for Disease Control. (2008). Fact Sheet
  River Blindness. Retrieved October 20, 2009 from
  http//www.cdc.gov/ncidod/dpd/parasites/onchocerc
  iasis/factsht_onchocerci asis.htm
• Department of Water Affairs and Forestry.
  (n.d.). River Photos. Retrieved October 20
• from http//www.dwaf.gov.za/iwqs/rhp/stat
  e_of_rivers/state_of_umngeni_02/pho tos/upper_umng
  eni_800.jpg
• Eezzuduemhoi, D.R. Wilson, D. Onchocerciasis.
  Retrieved October 20, 2009 from
  http//emedicine.medscape.com/article/1204593-ove
  rview
• Goldbamboo. (2009). Onchocerciasis Pictures.
  Retrieved October 20, 2009 from
  http//www.goldbamboo.com/pictures-t2268.html
• Nations Online. (2009). Map of Africa. Retrieved
  October 15, 2009 from http//www.nationsonline.or
  g/maps/africa_small_map.jpg
• Opoku, F.B. (2009). River blindness fly makes
  tasty meal for midges. Retrieved October 20,
  2009 from http//www.jrsbdf.org/v2/docs/Ghanaian
  20Journal20- 20River20Blindness20Fly.pdf.

14
References (continued)

• Poolman, E.M. Galvani, A.P. (2006). MODELING
  TARGETED IVERMECTIN TREATMENT FOR CONTROLLING
  RIVER BLINDNESS. Retrieved October 20, 2009 from
  http//www.ajtmh.org/cgi/reprint/75/5/921
• The Carter Center. (2009). River Blindness.
  Retrieved October 20, 2009 from
  http//www.cartercenter.org/health/river_blindnes
  s/index.html?gclidCICq ksjwy50CFSUMDQoddRmpqw
• UC Davis. 2006. Onchocerca volvulus. Retrieved
  October 15, 2009 from http//plpnemweb.ucdavis.
  edu/NEMAPLEX/Taxadata/Ov olvulus.HTM
• University of Tuebingen. (n.d.). O. volvulus life
  cycle image. Retrieved October 20, 2009 from
  http//www.tuniuebingen.de/modeling/images/O_volvu
  lus LifeCycle.gif
• World Health Organization/Tropical Disease
  Research. (2004). Onchocerca volvulus. Retrieved
  October 20, 2009 from https//apps.who.int/tdr/di
  seases/oncho/default.htm
•