Close up of an eye affected by ^Iconjunctivitis^i also known as red or pink eye. The infection affects the conjuctiva, the delicate mucosa that covers the front of the eye and lines the inside of the eyelids. It occurs here in a child of 7 days old producing a watery and pus-containing discharge. The infection causes discomfort rather than pain and does not usually affect vision. In this case it is caused by ^ITrichomonas,^i a genus of parasitic flagellate protozoans and is treated with antibiotics such as tetracycline and erythromycin.