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Candace Wells, MPH Student Walden University PUBH 6145-4 Dr. Robert Marino Winter Term, 2010. Onchocerciasis Disease (River Blindness). After this presentation…. Define Onchocerciasis Where does the name River Blindness come from Who and how one becomes infected Signs and symptoms
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Candace Wells, MPH Student Walden University PUBH 6145-4 Dr. Robert Marino Winter Term, 2010 Onchocerciasis Disease(River Blindness)
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
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 http://entoplp.okstate.edu/ddd/insects/blackflies.htm The Centers for Disease Control and Prevention[CDC] (2010a). Onchocerciasis-Disease. Retrieved from http://www.cdc.gov/parasites/onchocerciasis/disease.html
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 http://www.cdc.gov/parasites/onchocerciasis/disease.html
Signs and symptoms • Some do not exhibit symptoms • Others show: • Itchy skin rashes • Nodules under skin • Vision changes
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 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, 1454-1460.
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 World Health Organization [WHO] (2010). Prevention of Blindess and Visual Impairment: Onchocerciasis (river blindess)-Disease information. Retrieved from:http://www.who.int/blindness/partnerships/onchocerciasis_disease_information/en/index.html
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 World Health Organization [WHO] (). Prevention of Blindess and Visual Impairment: Onchocerciasis (river blindess)-Disease information. Retrieved from http://www.who.int/blindness/partnerships/onchocerciasis_disease_information/en/index.html
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
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, 1454-1460.
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% World Health Organization [WHO] (2006). Weekly epidemiological record (30) 293-296.
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
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.
Questions/ Comments • For any questions or comments please feel free to contact me at: • Candace.wells@waldenu.edu
References: • The Centers for Disease Control and Prevention[CDC] (2010a). Onchocerciasis-Disease. Retrieved from http://www.cdc.gov/parasites/onchocerciasis/disease.html • The Centers for Disease Control and Prevention [CDC] (2010b). Onchocerciasis FAQs. Retrieved from http://www.cdc.gove/parasites/onchocerciasis/gen_info/faqs.html • World Health Organization [WHO] (). Prevention of Blindness and Visual Impairment: Onchocerciasis Control Programme (OCP). Retrieved from http://www.who.int/blindness/partnerships/onchocerciasis_OCP/en/index.html
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, 1454-1460. • World Health Organization [WHO] (2010). Prevention of Blindess and Visual Impairment: Onchocerciasis (river blindess)-Disease information. Retrieved from http://www.who.int/blindness/partnerships/onchocerciasis_disease_information/en/index.html • World Health Organization [WHO] (2006). Weekly epidemiological record (30) 293-296.
For Further Reading • The Carter Center (2011). River Blindness Program. http://www.cartercenter.org/health/river_blindness/index.html • The World Bank (2011). African Program for Onchocerciasis Control, Phase II. http://go.worldbank.org/EEZUW32F20 • Hall, L.R., Pearlman, E, (1999). Pathogenesis of OnchocercalKeratitis (River Blindness). Clinical Microbiology Reviews (12), 3, 445-453.