Chlamydial pneumonia in Costa Rica: results of a case-control study.

This paper presents a brief review of chlamydial pneumonia in infancy and indirect evidence that the incidence of this disease may be high in developing countries. The results of a case-control study in Costa Rica, involving 39 cases of pneumonia and 43 controls (cases of diarrhoea), suggest that chlamydial pneumonia is of considerable public health importance there. Thirteen out of the 39 (33%) cases of pneumonia had serum antibody to Chlamydia trachomatis serovars D, E, F, G and L2, whereas only 1 out of the 43 controls was IgM-antibody positive (P<0.001). The occurrence of chlamydial pneumonia as a major health problem in developing countries is discussed.