A novel model for Avian Chlamydiosis by throat inoculation in SPF chickens

• 1、College of Veterinary Medicine, China Agricultural University, Beijing 100193

Abstract：Fifteen-day-old specific pathogen free chickens were given 5×108.5TCID50/0.1mL of four strains of Chlamydia psittaci by ocular-intranasal way and by throat injection, including 6BC, CB7, CB3 or HJ strains. Our current study aims to establish Chlamydia psittaci model in SPF chickens. Post inoculation by throat way, SPF chickens were observed to have lower feed take, and poor activity of drinking water as well as body weight gain. The average body-weight gain of infected chickens was 30.2%, 24.7%, 13.8% and 25.1%, respectively as compared to that of 46.5% in healthy group as the control. Moreover, the pathologies were characterized as fibrinous airsacculitis, pericarditis, peritonitis and pneumonia. More important, local hemorrhagic lesions were characterized in livers and bursa fabricius. In comparison with eye-intranasal route, more severe pathological lesions were observed in birds post inoculation by throat route. Furthermore, antibody was not detected on day 3, found to increase dramatically on day 7 and to decrease on day 10 post infection. From above data, 15-old-day SPF chickens displayed the typical lesions of avian Chlamydiosis by throat administration with above 4 strains while CB7 strain from ducks and HJ strain originated from pigeons are confirmed to be high pathogenic for SPF chickens. It is the first time that immune injury has been reported post inoculation with Chlamydia psittaci.

Keywords： Model Chlamydia psittaci throat inoculation pathogenicity SPF chickens