English: Illustration depicting a chlamydia-infected cell (pink and red oval shape). Chlamydia trachomatis bacteria (represented by small spherical shapes colorized brown) undergo development within a membrane-enclosed "inclusion body" (center area; orange). The dark red area on the right of the illustration denotes the cell nucleus. In the background is a CDC micrograph of cells (yellow) exhibiting chlamydia inclusion bodies (red). Credit: NIAID and CDC