Chlamydia trachomatis causes which of the following?

• A. Rat-bite fever
• B. Inclusion conjunctivitis
• C. A skin disease found predominantly in tropical areas
• D. Zoonosis in birds and parrot fever in humans

Answer: (B)

Chlamydia trachomatis is an intracellular bacterium that causes ocular infections known as inclusion conjunctivitis. This condition presents with redness and a mucopurulent discharge, and under the microscope you see characteristic inclusions inside conjunctival epithelial cells. It’s one of the classic diseases caused by this organism, along with trachoma and certain sexually transmitted infections.

Other options are caused by different pathogens: rat-bite fever comes from Streptobacillus moniliformis (or Spirillum minus in some cases); a tropical skin disease points to other organisms such as treponemes or fungi; and parrot fever (psittacosis) is caused by Chlamydia psittaci, not Chlamydia trachomatis. So the condition tied specifically to Chlamydia trachomatis in this context is inclusion conjunctivitis.