PRIMARY PATHOGENICITY OF AN EUROPEAN ISOLATE OF CHLAMYDIA-PSITTACI FROM TURKEY POULTS

Chlamydia psittaci was isolated as the sole pathogenic agent from a se vere outbreak of respiratory disease in a commercial broiler turkey fa rm in the Netherlands. The mortality rate in the flocks was 65%. Clini cal signs included conjunctivitis, swelling of the sinus infraorbitali s and sneezing. Cloacal excretion of chlamydia was demonstrated in twe lve out of fifteen birds examined by a direct immunofluorescence test. In all the fifteen birds antibodies against Chlamydia psittaci were d etected in the sera by a competitive ELISA. At necropsy sinusitis, rhi nitis, airsacculitis, pneumonia, pericarditis and enlargement of the l iver and spleen were found. Chlamydiae were demonstrated in the sinus material of all and in conjunctival smears of eight of the fifteen exa mined birds. Chlamydiae were isolated from all the examined birds afte r one to three passages on Buffalo Green Monkey (BGM) cell cultures us ing samples taken from lung, liver and spleen. No other pathogens were isolated. The chlamydia isolate was typed using a panel of serovar-sp ecific monoclonal antibodies in a micro-immunofluorescence test. The i solate belonged to the avian Chlamydia psittaci serovar D. Experimenta l inoculation with this isolate of 7-day-old specific pathogen free (S PF) turkeys resulted in severe clinical signs, with mortality and exte nsive pathological lesions, similar to those seen in turkeys from the examined broiler turkey farm. From the data it was concluded that this Chlamydia psittaci isolate can cause severe disease in turkeys.