Trachoma is the leading cause of preventable blindness

• • • Trachoma is the leading cause of preventable blindness in humans and is also caused by Chlamydia trachomatis obtained through contact of infected eye discharge or from “eye-seeking” flies The first sign of trachoma are mild discharge and inflammation followed by marked infiltration of lymphocytes and macrophages. This infiltration leads to a pebbled appearance to the upper eyelid and soon pseudomembrane forms over the cornea. Affects about 21. 4 million people of whom 2. 2 million are visually impaired and 1. 2 million are blind. ” Highly prevalent in Africa, Asia, and Central and South America O. Packer F 2013 Modified by DYH

O. Packer F 2013 Modified by DYH • • • Life Cycle of C. trachomatis Elementary body (EB), (non-replicating form of chlamydia) comes into contact with a eukaryotic host cell’s mammalian genital tract, conjunctivae, or respiratory tract and proteins from the EB enter into the host cell to assist in the phagocytosis of the EB. Within the host cell, the elementary body changes to the replicating form of chlamydia, called the reticulate body (RB). RB replicates in a “membrane-bound vacuole, ” called an inclusion. Integral membrane proteins called Inc proteins alter the inclusion that holds the replicating RB. Inc proteins interact with host cytosolic factors to establish a chlamydia factory that acquires lipids and nutrients from other host organelles” while avoiding parts that would destroy it. RB are converted back to elementary bodies and released soon after. video on developmental cycle Another Video Link