Respiratory and Pericardial Lesions in Turkeys Infected with Avian or Mammalian Strains of Chlamydia psittaci

Three groups of turkeys were inoculated with strains of C. psittaci (B577, VS1, TT3) from different restriction endonuclease groups. Turkeys were necropsied at 15 times through post-inoculation day 70. Birds infected with the TT3 strain were lethargic and had decreased body weight. After forced exercise, dyspnea was seen in VS1-infected turkeys. Pericarditis was the most severe lesion in TT3-infected birds. Airsacculitis and bronchopneumonia were the most severe lesions in VS1-infected turkeys. Lateral nasal adenitis was in both VS1- and TT3-infected birds. Only mild peribronchial pneumonia was in B577-infected turkeys. Chlamydial antigen, identified by light microscopy using an immunoperoxidase technique, was seen from post-inoculation days 9 through 50 in the lateral nasal gland and at earlier times in other tissue from VS1- and TT3-infected turkeys. No chlamydial antigen was detected in tissue from B577-infected birds. These studies showed that chlamydial strains from different restriction endonuclease groups are associated with distinct disease syndromes in turkeys.