the world's second leading infectious cause of blindness Pooja
Makam
Slide 2
Prevalence! 95% + of cases occur within 30 African countries!
17.7 Million INFECTED! 40% of cases are in Nigeria!!! 300, 000
people are blind
Slide 3
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!!
Slide 4
Causative Agent Black fly- Simulium Onchocerca volvolus
Slide 5
How do we get sick from a fly?
Slide 6
Death of Microfilaria Inflammatory Response
Slide 7
Diagnosis Presence of microfilaria in blood, urine and
eyes
Slide 8
Treatment Medication= Ivermectin Kills by paralyzing
microfilariae(larvae) NO Reproduction NO Inflammatory Resonse- No
Lesions
Slide 9
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
Slide 10
Repeated Ivermectin exposure Resistance! Due to genetic changes
in parasite genetic marker = -tubulin gene Roger Prichard (McGill
University, Canada) and colleagues
Slide 11
No Vaccinations!! Currently no safe drug available to cure this
disease or prevent it! FUTURE?? Research: Some Cattle develop
natural immunity to disease
Slide 12
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 !
Slide 13
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
Slide 14
Treatment Span OCP= (green) APOC=(yellow)
Slide 15
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