Abstract

The cytological and ultrastructural findings of Pneumocystis carinii(PC) obtained from rats by bronchoalveolar lavage(BAL) are described. All developmental forms of the PC organisms were obtained in the lavage fluid. Ultrastructurally, the cysts were almost circular in shape, and were nearly devoid of surface tubular extensions. The wall of the cyst was composed of an unit membrane, and intermediate electron lucent layer and an external electron dense layer. The cysts frequently contained intracystic bodies, so called sporozoites. Occasionally empty or collapsed cysts with no intracystic bodies, and precysts were found. Trophozoites were variable in size and shape with abundant tubular extensions along the single electron dense pellicle. BAL is a useful method for concentrating the various morphologic forms of PC organisms, and is a rapid diagnostic method for PC pneumonia.

• Keywords: Pneumocystis carinii;Cytology;Ultrastructure;Bronchoalveloar lavage;