The causative agent is ''Cillia-associated respiratory bacillus''. It is an unclassified bacteria that can't be grown in culture. It colonises ciliated epithelium in '''rodents''' and ruminants. | The causative agent is ''Cillia-associated respiratory bacillus''. It is an unclassified bacteria that can't be grown in culture. It colonises ciliated epithelium in '''rodents''' and ruminants. |