Chlamydia are bacteria-like obligatory intracellular parasites. Although they were considered once to be large viruses, they differ from the viruses in having two nucleic acids and in having a discrete cell wall. They do resemble viruses only in the obligatory intracellular nature of their parasitism.1.2
A number of human diseases are caused by Chlamydia. Recent studies have shown that chlamydial infection in the newborn is associated with a pneumonia syndrome that is characterized by an afebrile course, chronic diffuse lung involvement, tachypnea, and elevated serum IgG and IgM levels.3-5
In the 2-week-old infant with severe pneumonitis who is to be described, C trachomatis was isolated from tracheal aspirates as well as from her mother's cervix.
Report of a Case.—A 4,100-g term female infant was born to a 30-year-old mother, after a normal pregnancy, labor, and delivery. There was no maternal history of conjunctivitis, or of respiratory