Infectious Coryza Modelling in Chickens Using Indonesian

Avibacterium paragallinarum is the causative agent of infectious coryza in chickens, characterized by reduced egg production and elevated morbidity. Despite the extensive reporting of this illness, data on the pathogenicity and infection dynamics of local Indonesian isolates are limited. This research aimed to evaluate the infection model for local Indonesian isolates of A. paragallinarum in chickens. Four groups of chickens were utilized: a control group, an A. paragallinarum inoculation group, a Staphylococcus aureus coinfection group, and a natural transmission group. The bacteria were inoculated into the infraorbital sinus, and clinical symptoms were observed, daily average scores were recorded, and confirmation was performed by PCR using HPG-2 primers. The test findings demonstrated mild clinical impacts, including swelling of the infraorbital sinus, in the inoculated group, while the natural transmission group showed no clinical symptoms. The mean daily score in the A. paragallinarum inoculation group rose from 0.3 on day 7 to 0.4 on day 14. Simultaneously, the coinfection cohort showed a decline in score from 0.3 on day 7 to 0.1 on day 14. The HPG-2 PCR test identified the infection prior to the onset of clinical manifestations. The peak of infection occurred on day 7, with 6 of 10 chickens in the inoculation group, 10 of 10 in the coinfection group, and 8 of 10 in the natural transmission group positive. The results validate that local Indonesian A. paragallinarum isolates exhibit varying levels of pathogenicity, and the infection model developed may represent disease dynamics for further study and the development of management strategies.