Occurrence of conjunctivitis, sinusitis and upper region tracheitis in Japanese quail (Coturnix coturnix japonica), possibly caused by Mycoplasma gallisepticum accompanied by Cryptosporidium sp. infection.

On a farm raising approximately 75,000 Japanese quail (Coturnix coturnix japonica) for egg production, the diseased quail showed clinical signs of swelling of the head, nasal discharge, increased lacrimation, and decreased egg production. The flock experienced a mortality rate of 5.7% per day. Macroscopic observation revealed large, gelatinous masses of caseous exudate in the sinuses, egg peritonitis, and airsacculitis. Microscopically, non-purulent or purulent inflammation accompanied by lymphoid hyperplastic tissue with germinal centers was observed in the oculofacial respiratory mucosa. The developing stage of the lesions was abscess formation. In the investigation of pathogens, antigens to Mycoplasma gallisepticum and Pasteurella multocida serotype D were immunolabeled on and demonstrated in the mucosal membranes. In addition, P. multocida, Escherichia coli, Staphylococcus sp., and Streptococcus sp. were isolated from the infraorbital sinuses, and Mycoplasma isolated from a diseased bird was confirmed as M. gallisepticum by polymerase chain reaction (PCR). Furthermore, Cryptosporidium sp. was frequently found in the brush border. Serological, bacteriological and PCR examinations, some with negative outcomes, were carried out concerning microbes that are known to cause swollen heads in birds (Haemophilus paragallinarum, Newcastle disease virus and turkey rhinotracheitis virus). The average concentration of ammonia fumes in the cages was 30.6 parts/106, which suggests that the high levels of ammonia fumes promoted infection and multiplication of M. gallisepticum in the quail, and that the clinical disease then worsened due to mixed infection with M. gallisepticum and Cryptosporidium sp. or other bacteria.