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the world's second leading infectious cause of blindness Pooja Makam

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Prevalence! 95% + of cases occur within 30 African countries! 17.7 Million INFECTED! 40% of cases are in Nigeria!!! 300, 000 people are blind

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Whos at Risk?? West Africa Central/South America Yemen People living near fast moving rivers Fast Moving Water is Well oxygenated= Great breeding ground! 78 millon people at risk!!

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Causative Agent Black fly- Simulium Onchocerca volvolus

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How do we get sick from a fly?

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Death of Microfilaria Inflammatory Response

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Diagnosis Presence of microfilaria in blood, urine and eyes

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Treatment Medication= Ivermectin Kills by paralyzing microfilariae(larvae) NO Reproduction NO Inflammatory Resonse- No Lesions

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Mechanism of Ivermectin Glutamate-gated Chloride Channels- found only in Invertebrate Inhibitory Postsynaptic Potential (IPSP) decreases future action Potential Paralysis DEATH Irreversibly activates channel receptors in worm

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Repeated Ivermectin exposure Resistance! Due to genetic changes in parasite genetic marker = -tubulin gene Roger Prichard (McGill University, Canada) and colleagues

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No Vaccinations!! Currently no safe drug available to cure this disease or prevent it! FUTURE?? Research: Some Cattle develop natural immunity to disease

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Socioeconomic Impact Blindness = up to 50% of adults in W. Africa Abandoned the fertile river -valleys in fear of contracting the disease + adults were blind and could not work Poverty and famine!! 1974: economic losses =$30 million need for Prevention Programs !

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Prevention: VECTOR CONTROL Onchocerciasis Control Programme-OCP in West Africa(1974) African Program for Onchoceriasis Control APOC- (1997) Pesticide Spraying Clear brush/vegetation from the banks of fast running streams to reduce the number of flies Avoid sleeping outdoors in the day time

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Treatment Span OCP= (green) APOC=(yellow)

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References: http://www.who.int/topics/onchocerciasis/en/ http://www.utmb.edu/gsbs/microbook/images/fig92_3.JPG http://images.google.com/imgres?imgurl=http://www.stanfor d.edu/group/parasites/ http://www.dpd.cdc.gov/dpdx/HTML/Filariasis.htm http://images.google.com/imgres?imgurl=http://www.mectiza n.org/images/onchoafricamap.jpg TRD Wellcome trust Scientists Step Closer To New Treatments For River Blindness- ScienceDaily (Apr. 16, 2006) River Blindness Parasite Becoming Resistant To Standard Treatment-ScienceDaily (Sep. 5, 2007) WHO CDC