ACANTHAMOEBA There are four species belongs to Acanthamoeba species Acanthamoeba culbertsoni – formely known hartmanella culbertsoni Acanthamoeba polyphaga Acanthamoeba castellani Acanthamoeba astromyxis

PROPERTIES OF ACANTHAMOEBA SPECIES  They have trophozotes They have polygonal double walled cysts They differ from naegleria in not having flagellate stage and in forming cysts in tissues SOURCES OF INFECTION OF ACANTHAMOEBA Infection can be acquired by Inhalation Ingestion Traumatized skin or eyes From contaminated water

PATHOGENESIS OF ACANTHAMOEBA SPECIES Following inhalation of acanthamoeba cyst the organism migrate into the upper and lower respiratory tract and then enter the blood circulation and reach the brain where continues to multiply and produce more cyst which cause granulomatous amoebic encephalitis. For the case of chronic amoebic keratitis or keratouvetis of which over a thousands cases have been reported develops from the entry of amoebic cyst through abrasion on the cornea. The large majority of such cases have been associated with the use of contact lenses.

CLINICAL FEATURES GRANULOMATOUS AMOEBIC ENCEPHALITIS Patient presenting with the following neurological signs and symptoms: Seizures Fever Cranial nerve paralysis Abnormal reflexes Muscle weakness Personality changes Confusion Comatose

CHRONIC AMOEBIC KERATITIS Patient presents with the following features Difficult in vision Painful the eye Tearing Light sensitivity Blindness

DIAGNOSIS OF ACANTHAMOEBA Diagnosis of chronic keratitis is by demonstration of the cyst in cornea scraping by wet mount, histology and by culture. Growth can be obtained from the corneal scrapings inoculated on a nutrient agar, overlaid with live or dead Escherichia coli Diagnosis of granulomatous amoebic encephalitis is by examination of cerebrospinal fluids (CSF). CSF shows lymphocytic pleocytosis. Acanthamoeba trophozotes and cysts can be demonstrated in brain biopsy by microscopy, culture and immunofloresence using monoclonal antibodies.

TREATMENT Treatment with drugs such as propamidine, polyhexamethylene biguanide, chlorhexidine and ketoconazole along with surgical procedures has been found useful.

REFERENCE Text book of medical parasitology, 6th Edition, by CK Jayaram Paniker