1. RIVER BLINDNESS Kenetra Ruffin, MBA/HCM, BSMT, BB(ASCP)
PhD Candidate Public Health Epidemiology
Walden University
PUBH
Instructor: Dr. Rebecca Heick
Fall 2009
Hello everyone! My name is Kenetra Ruffin. I am a PhD student at Walden University in the Public Health Epidemiology program. My presentation is on a condition known as River Blindness. I hope that you enjoy and learn from the material. Please let me know if you have any questions. Thank you!

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
This is a list of the contents and learning objectives that I will be covering today.

3. What is River Blindness?
The medical term is called Onchocerciasis.
It is the world’s 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
River blindness spreads person to person by the bite of an infected blackfly (Centers for Disease Control and Prevention [CDC], 2008). The disease is preventable, and it causes serious obstacles to the socioeconomic development in Africa (WHO/TDR, 2004).

4. References: Eezzuduemhoi & Wilson, 2008; WHO/TDR, 2004
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 .
The pictures on the slide is of the blackfly that bites its victims and the adult worm that forms inside of infected individuals. O. volvulus is the only parasitic worm of the Onchocerca species with a human host (Eezzuduemhoi & Wilson, 2008). The lifespan of the parasite without a host is 4 weeks. Inside of a human host, the parasite can live up to 15 years.
References: Eezzuduemhoi & Wilson, 2008; WHO/TDR, 2004

5. Life Cycle of Onchocerca volvulus
This picture represents the life cycle of the parasite that causes river blindness. The human host is infected with the larvae by the bite of the blackfly. Then the larvae develops into an adult filariae in subcutaneous tissues of the host. Adult worms are then bounded by connective tissue and can be palpated as nodules through the skin. Some of the nodules contain numerous adult male and female worms that can reach up to 15 years of age. The female worm measures between 33 to 50 cm in length and 270 to 400 m in diameter. The male worm only reaches 19 to 42 mm in length and 130 to 210 m in diameter. Female worms are capable of producing their offspring, called microfilariae, for approximately 9 years while the parasite lives inside the host. The microfilariae can survive for up to 2 years and are found in the skin and connective tissues. Black flies ingest some of these microfilariae when they bite an infected host and the microfilariae migrate to the thoracic muscles of the blackfly. That is where the intra-cellular parasites live and develop into what is known as the infective larva. At this stage, the parasite migrates to the blackfly's proboscis and is able to infect another human (University of Tuebingen, n.d.).
Reference: University of Tuebingen, n.d.

6. References: Goldbamboo, 2009; WHO/TDR, 2004
Signs & Symptoms
Nodules
Debilitating pruritus
Malnutrition
Stigmatizing skin lesions
Depigmentation of the skin
Skin rashes
Intense itching
Elephantiasis of the genitals
Visual Impairment
Blindness
The raised nodules can be seen under the skin. These nodules occur because the parasite larvae are immobilized in those locations while the host is sleeping and are trapped by the body's cellular defense mechanisms (UC Davis, 2006). The leopard skin appearance is a result of the lost of pigmentation of the host’s skin. The infected hosts are very uncomfortable and become fatigued and malnourished.
References: Goldbamboo, 2009; WHO/TDR, 2004

7. References: Goldbamboo, 2009; UC Davis, 2006
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.
Some host can actually feel and see the parasitic worms move across their eyes. Over a period of time the eye becomes inflamed, infected, irritated and the host becomes blind. The blindness debilitates the host and they are unable to work and perform some of their usual daily activities (WHO/TDR, 2004).
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.
The transmission of the parasite is most intense in remote African rural agricultural villages that are located near rapidly flowing streams (CDC, 2008). The eggs of the parasite require fast-running rivers for breeding grounds. The adult worms emerges after 8-12 days following egg production and have the ability to travel hundreds of kilometers by flight on wind currents (Eezzuduemhoi & Wilson, 2008).
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.
There are 36 countries in total that have reported river blindness cases. The vast majority of those countries are in tropical areas of Africa where 99% of infected people live. There are also isolated foci in 6 countries located in Latin America and Yemen (WHO/TDR, 2004).
References: UC Davis, 2006; Nations Online, 2009

10. Reference: Eezzuduemhoi & Wilson, 2008
Morbidity/Mortality
About 85.5 million people live in the endemic areas.
An estimated 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
Over 90% of certain village populations in Africa are infected with river blindness, and about 35-50% of these people have ocular Onchocerciasis (Eezzuduemhoi & Wilson, 2008). Men may be affected more often than women because of their occupations in the fields and on farms. Approximately 50% of people who are 40 years old or older may be blind in endemic areas (Eezzuduemhoi & Wilson, 2008).

11. Reference: Poolman & Galvani, 2006
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
The primary and secondary use of ivermectin will help to reduce the disease burden and transmission of river blindness. Operational conditions in Africa make it difficult to properly implement and maintain vector control programs and these programs use chemicals to remove the blackflies. Morbidity of river blindness will be heightened if the treatment of ivermectin ends (Poolman & Galvani, 2006). Other vector ideas include the use of biological agents that will consume the vector. Midges, Cardiocladius oliffi, have the ability to hunt blackflies and eat them at the immature stages. This will help to reduce the amount of adult flies that could become infected and transmit the disease (Opoku, 2009).

12. Reference: The Carter Center, 2009
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
The individuals who live in the endemic areas are bitten as many as 20,000 times a year by infected blackflies (The Carter Center, 2009). The population in these endemic countries are poor and are suffering and can not protect themselves from the blackflies. Visitors and travelers to endemic countries are not in great risk of contracting the parasite. However, they should wear long sleeves and pants to protect themselves from insect bites. Thank you very much for attention. Are there any questions?

13. References
Centers for Disease Control. (2008). Fact Sheet: River Blindness. Retrieved October 20, 2009 from asis.htm
Department of Water Affairs and Forestry. (n.d.). River Photos. Retrieved October 20
from tos/upper_umngeni_800.jpg
Eezzuduemhoi, D.R. & Wilson, D. Onchocerciasis. Retrieved October 20, 2009 from
Goldbamboo. (2009). Onchocerciasis Pictures. Retrieved October 20, 2009 from
Nations Online. (2009). Map of Africa. Retrieved October 15, 2009 from
Opoku, F.B. (2009). River blindness fly makes tasty meal for midges. Retrieved October 20, from %20River%20Blindness%20Fly.pdf.

14. References (continued)
Poolman, E.M. & Galvani, A.P. (2006). MODELING TARGETED IVERMECTIN TREATMENT FOR CONTROLLING RIVER BLINDNESS. Retrieved October 20, 2009 from
The Carter Center. (2009). River Blindness. Retrieved October 20, 2009 from ksjwy50CFSUMDQoddRmpqw#
UC Davis Onchocerca volvulus. Retrieved October 15, from olvulus.HTM
University of Tuebingen. (n.d.). O. volvulus life cycle image. Retrieved October 20, from LifeCycle.gif
World Health Organization/Tropical Disease Research. (2004). Onchocerca volvulus. Retrieved October 20, 2009 from