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BB 30052 Scientific Communication The pathophysiology of Acanthamoeba K eratitis. Junho Jung 30 th April 200 7. Introduction. What is Acanthamoeba ? One of the most common protozoa in soil, and also frequently found in fresh water Most species are free-living bacterivores
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BB30052Scientific CommunicationThe pathophysiology ofAcanthamoeba Keratitis Junho Jung 30thApril 2007
Introduction • What is Acanthamoeba? • One of the most common protozoa in soil, and also frequently found in fresh water • Most species are free-living bacterivores • some are opportunists that can cause infections in humans and other animal • Relatively rare disease. However in2002, between 17 and 21Acanthamoeba infection cases per million contact-lenswearers reported in UK.
Acanthamoeba as a human pathogen • Acanthamoeba causes amoebic keratitis and encephalitis • Eye infection has been associated with contact lens use • Also enter the skin through a wound or nostrils. Amoebas can travel to the lungs and through the bloodstream to central nerve system, cause fatalinfection called granulomatous amebic encephalitis (GAE).
Symptoms of Acanthamoeba infection • A corneal ulcer may result from exposures. This could be sight-threatening without proper treatment. • Acanthamoeba spp. can cause skin lesions and a systemic (whole body) infection. • GAE Patients may suffer with headaches, stiff neck, nausea, vomiting, tiredness, confusion, lack of attention, loss of balance and bodily control, seizures, and hallucinations.
The pathogenic cascade of Acanthamoeba keratitis • Attachment • Destruction of epithelium and upregulation of MMPs • Breachment of Bowman’s membrane • Degradation of stroma • Radialneuritis
Treatment for infection with Acanthamoeba • Eye and skin infections are generally treatable. Treatment is most effective when the diagnosis is made promptly. • Because the cyst may form, and can be highly resistant to therapy, a combination of agents is generally used. • Although most cases of brain (CNS) infection with Acanthamoeba have been fatal, a few have recovered from the infection with proper treatment.
Acanthamoeba and MRSA • Recent findings from the University of Bath demonstrate that MRSA can infect and replicate inside of Acanthamoeba polyphaga; • Since A. polyphaga can form cysts, cysts infected with MRSA can act as a mode of airborne dispersal for MRSA.
Concluding remarks • A better understanding of the pathogenic cascade of Acanthamoeba keratitis could lead to improved clinical treatment of this and other amebic infections. • Might be possible to develop Multivalent mucosal vaccines that induce multiple secretory IgA antibodies that target the lectin-binding molecules on the surface of the amoeba and the proteases that are released during invasion of the mucosal surface.