Middle ear infection in feedlot lambs

Of 133 feedlot lambs that died and were necropsied, 67 had normal lungs and 66 had pneumonic lungs. The middle ears of all lambs were opened by a specified technique. Of the 67, 8 (12%) had otitis media, and of the 66, 26 (39%) had otitis media. The difference in prevalence in the 2 groups was highly significant (P less than 0.005). In acute stages, the mucosae of tympanic cavities and tympanic membranes were inflamed and the cavities contained fluid, whereas in later stages lumens were partially filled with exudate. In chronic stages, however, exudate remained in lumens and mucosae were thick and rough. None of the tympanic membranes was ruptured, and none of the external acoustic meatuses contained exudate. The infected ears of 24 lambs were cultured and Pasteurella haemolytica was isolated from 18, and P multocida from 3. The infections probably ascended from the pharynx through the auditive tubes into the tympanic cavities.

Suppurative otitis media in the rabbit: prevalence, pathology, and microbiology

The middle ears of 2001 young and 583 adult rabbits being slaughtered for human consumption were examined. Otitis media was found in 87 (4%) of the young rabbits, and in 188 (32%) of the adult rabbits. The condition was bilateral in 61% of the affected young rabbits and 70% of the affected adults. Pasteurella multocida was isolated from 60 (98%) of 61 affected young rabbits. The gross and microscopic lesions and secondary complications were similar to those described in children. Rupture of the tympanic membrane was observed in both affected young and affected adult rabbits.

Otitis media of guinea pigs

Otitis media occurred in 177 of 1373 guinea pigs necropsied during a six-year period. Streptococcus pneumoniae (20%), Streptococcus zooepidemicus (15%), Bordetella bronchiseptica (12%), and Pseudomonas aeruginosa (11%) were the most common bacteria isolated from affected tympanic bullae. Radiology and otoscopy were tested as means of antemortem screening for affected guinea pigs. Radiology gave 96% accuracy in diagnosing otitis media and proved to be a more satisfactory technique than otoscopy.

Bulla curettage for chronic otitis media and interna in dogs

In a series of 10 clinically affected and 6 clinically normal dogs, the technique of bulla curettage via the external ear canal, after lateral ear resection, was evaluated. In 5 of the 10 dogs with chronic otitis media and interna, the head carriage became normal 2 to 8 weeks after surgery and remained so for at least 18 months; 4 other dogs improved, but the improvement was either temporary or incomplete. In the clinically normal dogs, postsurgical complications were minimal; the tympanic membrane healed completely in 4 of the 6 dogs.

Self-mutilation in mice associated with otitis media

Mutilation of the external ear and adjacent tissues was an enzootic problem in outbred Mcr:(ICR) breeder mice in a commercial colony. Necropsy examination of affected and randomly selected, nonaffected adult breeder mice revealed a probable association of the cutaneous lesions with suppurative otitis media. Several microorganisms, including Mycoplasma pulmonis and Pasteurella pneumotropica, were isolated from the tympanic bullae.