1. Onchocerciasis Disease (River Blindness)
Candace Wells, MPH Student
Walden University
PUBH
Dr. Robert Marino
Winter Term, 2010
Hello Ladies and Gentlemen. My name is Candace Wells and today I will be presenting information on Onchocerciasis Disease, better known as River Blindness. This presentation is designed to educate the population about this disease, this can include citizens in countries whom are affected and citizens from countries who may not know much about this disease.

2. After this presentation…
Define Onchocerciasis
Where does the name River Blindness come from
Who and how one becomes infected
Signs and symptoms
Know where is incidence and prevalence greatest
Describe prevention and control measures
Throughout this presentation I will be discussing key points to increase knowledge on this disease, in hopes to reduce incidence and the impact of this disease. Once I’m am done with this presentation you will be able to define Onchocerciasis and know where the name River Blindness comes from, learn how a person can become infected, pinpoint the countries where the greatest incidence and prevalence occurs and be able to describe prevention and control measures.

3. What is River Blindness?
Infection caused by parasitic worm Onchocerca volvulus
Spread by Simulium blackfly
Breads rapidly in fast flowing streams
Infection causes blindness
Black Fly adult
We start by answering the question: What is Onchocerciasis? Onchocerciasis is an infection caused by the parasitic worm Onchocerca volvulus, that is spread through the bite of an infected Simulium blackfly. It is also called river blindness because the fly that causes this disease breads quickly in fast-flowing rivers and the infection can cause blindness.
The Centers for Disease Control and Prevention[CDC] (2010a). Onchocerciasis-Disease. Retrieved from

4. How are we infected
Blackfly deposits O. volvulus into skin when attempting to extract blood.
Lives in fibrous nodules under skin where females can reproduce
Develop within the fly to infective stages, then transmissible to others
Adult larvae is detectable in the skin 10 to 20 months after initial infection.
The Centers for Disease Control and Prevention[CDC] (2010a). Onchocerciasis-Disease. Retrieved from
Humans become infected when the blackfly deposits O.vulvulus into the skin when attempting to extract blood. Once the larvae is inside the human body it matures into adults anywhere from 3 months to a year (CDC, 2010a). Most of the adults live in fibrous nodules underneath the skin and can be found sometimes near muscles.

5. Signs and symptoms Some do not exhibit symptoms Others show:
Itchy skin rashes
Nodules under skin
Vision changes
Once infected with O. volvulus, Some people do not exhibit symptoms and this can be because the larvae can migrate through the body without provoking an immune system response. Those who larvae provoke a response from the immune system will have itchy skin rashes, vision changes, and nodules under the skin.

6. Endemic where?
Basanez et al (2006) reports O. volvulus is endemic in 27 sub-Saharan African countries, Yemen, 6 Latin countries.
Estimated 37 million carry the disease, 90 million at risk in Africa
In order to prevent the spread of this disease we must know the causes, location and transmission of the disease. We’ve touched on the causes and transmission of river blindness, now we move into the location. River blindness is found in 27 sub-Saharan African countries and 6 Latin countries. It is estimated that 37 million people carry the disease, with 90 million people in Africa at risk.
Basanez, M.G., Pion, S.D.S., Churcher, T.S., Breitling, L.P., Little, M.P., Boussinesq, M, (2006). River Blindness: A success Story under Threat? Plos Medicine (3), 9,

7. Disease burden
Repeated years of exposure, lesions may lead to irreversible blindness and disfigurative skin diseases
50% of men in West African countries over the age of 40 have been blinded by this disease
Estimated annual economic loss in the 1970s was $30million
The real burden of this disease has been underestimated! Onchocerciasis is responsible for the annual loss of over 1 million disability-adjusted life years, which has greatly reduced a person ability to generate income (Basanez et al., 2006). As noted above, excessive mortality of the blind is known to happen in males. The disfigurative skin diseases can sometimes be called “leopard” or “lizard” skin (WHO, 2010)
World Health Organization [WHO] (2010). Prevention of Blindess and Visual Impairment: Onchocerciasis (river blindess)-Disease information. Retrieved from:

8. Onchocerciasis Control Program (OCP)
Launched by WHO in 1974
In collaboration with World Bank, the United Nations Development Programme (UNDP) and Food and Agriculture Organization (FAO)
Stretched over 1, 200, 000 km2 to protect 30 million people in 11 countries
Following the consequences of onchocerciasis in West Africa, The World Health Organization, better known as WHO, launched The Onchocerciasis Control Programme in This was done in collaboration with the World Bank, the United Nations Development Programme and Food and Agriculture Organization and stretched over 1,200,000 kilometers squared to protect over 30 million people in 11 different countries. (WHO, 2010). OCP countries include Benin, Ghana, Niger, Guinea ,Senegal
World Health Organization [WHO] (). Prevention of Blindess and Visual Impairment: Onchocerciasis (river blindess)-Disease information. Retrieved from

9. OCP
Previously based on spray of insecticides by helicopters and aircrafts
In 1987 control operations changed to larviciding combined with ivermectin treatment
Responsible for prevention of 600,000 cases of blindness
Mass administration of ivermectin once or twice a year reduces morbidity and disability and also lowers transmission
The success of the OCP program is exemplary with 600,000 cases of blindness prevented and 18million children born in areas free from the risk of blindness. When the program was first developed it sprayed insecticides by helicopters and aircrafts, in 1987 control operations changed to larviciding combined with ivermectin treatment. This change was possible with the donation of Mectizan (ivermectin) by Merck & Co. (WHO, 2010).

10. Control strategies cont
Onchocerciasis Elimination Program for the Americas (OEPA)
Initiated in 1993 to eliminate all morbidity from Onchocerciasis in the six affected Latin American countries
Based on biannual mass invermectin distribution
African Programme for Onchocerciasis (APOC)
Launched in 1995 in order to recover the remaining 19 African countries not protected under OCP
Based on annual invermectin distribution
Basanez, M.G., Pion, S.D.S., Churcher, T.S., Breitling, L.P., Little, M.P., Boussinesq, M, (2006). River Blindness: A success Story under Threat? Plos Medicine (3), 9,
Listed here are the different Onchocerciasis control programs.

11. Treatments in 2005
Brazil: 1.8% of the population in need of treatment for onchocerciasis.
Provided 13,483 treatments in during this year.
Reached 85% treatment coverage
Guatemala: 4 endemic foci, in which 39% of the population needing treatment
Provided 326,646 invermectin treatment
Surpassed 85% treatment coverage
Ecuador: single endemic focus and 4.5% of the population needing treatment
Provided 39,385 invermectin treatments
Achieved a treatment coverage of >85%
Listed are treatments done in 2005 in different countries. As you can see invermectin treatments were very successful in the countries listed. Each treatment coverage reached over 85%.
World Health Organization [WHO] (2006). Weekly epidemiological record (30)

12. Prevention
The best prevention is to avoid being bitten by infected blackfly
By using DEET on exposed skin
Wearing long sleeve shirts and pants
Wearing permethrin treated clothing
No Vaccine available
No drug available
This slide shows the few prevention strategies for this disease. As you can see, it is easier to control the spread of this disease instead of preventing the disease. If you are in the countries known to spread this disease, it can be difficult avoiding getting bitten. If you are in these countries you can use DEET on exposed skin, wear long sleeve shirts and pants, or wear permethrin treated clothing.

13. Conclusion
Onchocerciasis is a disease worth noting. With the help of the control programs such as the OCP, APOC, and OEPA, this disease is well on its way to being non-existent.
Although River Blindness is known as the neglected disease, there is still great importance in keep incidence and prevalence rates down. With the help of control programs such as OCP, APOC and OEPA, Onchocerciasis is well on its way to becoming non-existent. I hope I have provided you with all he information needed to increase you knowledge on this disease.

14. Questions/ Comments
For any questions or comments please feel free to contact me at:

15. References:
The Centers for Disease Control and Prevention[CDC] (2010a). Onchocerciasis-Disease. Retrieved from
The Centers for Disease Control and Prevention [CDC] (2010b). Onchocerciasis FAQs. Retrieved from
World Health Organization [WHO] (). Prevention of Blindness and Visual Impairment: Onchocerciasis Control Programme (OCP). Retrieved from

16. References cont…
Basanez, M.G., Pion, S.D.S., Churcher, T.S., Breitling, L.P., Little, M.P., Boussinesq, M, (2006). River Blindness: A success Story under Threat? Plos Medicine (3), 9,
World Health Organization [WHO] (2010). Prevention of Blindess and Visual Impairment: Onchocerciasis (river blindess)-Disease information. Retrieved from
World Health Organization [WHO] (2006). Weekly epidemiological record (30)

17. For Further Reading
The Carter Center (2011). River Blindness Program.
The World Bank (2011). African Program for Onchocerciasis Control, Phase II.
Hall, L.R., Pearlman, E, (1999). Pathogenesis of Onchocercal Keratitis (River Blindness). Clinical Microbiology Reviews (12), 3,
For further reading, take a look at the listed websites and article.