Chlamydia

Chlamydophilae are obligatory intracellular parasites incapable of generating their own energy source. Chlamydophilae depend on the host cell's adenosine triphosphate (ATP) for energy. Like bacteria, they can be eliminated by broad-spectrum antibiotics, but like viruses, they require living cells for multiplication. Once, Chlamydophilae were thought to be large viruses rather than bacteria due to their small size and dependence on the host cell. Some scientists suggested that Chlamydophilae, a 'primitive' bacteria, occupied the evolutionary space between traditional viruses and bacteria.

There are two distinct forms in the life cycle of Chlamydophilae: the intracellular form and the infective form. During the intracellular form, the Chlamydophilae reproduce within the host cell as many organisms as the host cell will hold. This occurs 35-40 hours after infection. Once full of Chlamydophilae organisms, the weakened cell bursts and dies. At this point, the Chlamydophilae organisms enter the infective form as it seeks more host cells to invade. In this form, the organisms are especially resistant and are transmitted to other hosts.

The name Chlamydia derives from the Greek word "chlamys" denoting the cloak-like mantle worn by men in Ancient Greece. The name was given to Chlamydiae organisms since they were believed to be intracellular protozoan pathogens that cloaked the nucleus of an infected cell. Scientists have since discovered that Chlamydiae are prokaryotic organisms, and what appeared to be a cloak was a cytoplasmic vesicle with countless individual organisms inside. Chlamydia trachomatis, the most famous Chlamydia disease, is the leading cause of preventable blindness in the developing word, and in the developed world, it is a sexually transmitted diseases responsible for infertility and pelvic inflammatory disease in women.