This report details the first experimental production of clinical disease, mortality, and pathology resembling that of field infections by using Ornithobacterium rhinotracheale alone. Twenty-two-week-old male turkeys were exposed to O. rhinotracheale or lung homogenate from O. rhinotracheale-infected turkeys. Within 24 hr after inoculation, turkeys given O. rhinotracheale or lung homogenate intratracheally were depressed and coughing and had decreased feed intake. By 48 hr, several birds were coughing blood and ultimately died. Grossly, the lungs were reddened, wet, and heavy, failed to collapse, and were covered by tenacious tan-to-white exudate. Microscopically, the parabronchi and air capillaries were filled with fibrin, heterophils, macrophages, and small numbers of gram-negative bacteria. The pleura was often covered by a thick layer of fibrin, heterophils, and macrophages. Turkeys that survived to day 7 postinoculation had severe, subacute pneumonia. Ornithobacterium rhinotracheale was recovered from the lungs of most birds with pneumonia and was also cultured from the air sacs, sinuses, tracheas, spleens, and livers. All turkeys inoculated with O. rhinotracheale developed antibodies to O. rhinotracheale detectable by the serum plate agglutination test.

Between July, 1993, and October, 1994, seven cases were examined that consisted of increased mortality in commercial turkeys due to cellulitis. The condition started at 13-16 wk of age in toms and persisted until the birds were marketed. The mortality rate was 1-2% per week. Lesions began on the ventrum of the tail and consisted of swelling and the formation of vesiclelike structures. Most of the affected birds also had an accumulation of gelatinous fluid in the subcutis of the tail and breast areas. The underlying musculature was often darkened or petechiated. Clostridium perfringens type A was isolated from two of the cases. Lesions similar to those found in the field were reproduced experimentally in turkeys injected with the subcutaneous fluid obtained from birds in field cases.

Increased death loss was seen in a flock of 22-wk-old tom turkeys. The predominant postmortem lesion was fibrinopurulent pneumonia and pleuritis. Within 5 wk, turkey flocks on 17 other farms developed similar problems. All affected flocks during the 5-wk period were between 14 and 22 wk of age, and the severity of clinical signs and the degree of mortality increased with age. Ornithobacterium rhinotracheale was isolated in pure culture from affected lungs. Further investigation by tracheal swab culture of 261 flocks between 5 and 7 wk of age resulted in detection of O. rhinotracheale in 43% of the flocks.

A virus adsorption-elution (viradel) procedure was modified and evaluated for the concentration of influenza virus from water. Influent pH, flow rate, eluent pH and composition, and a second-step concentration method were evaluated. The viradel procedure in combination with a chicken erythrocyte adsorption technique resulted in up to 3200-fold concentration of influenza virus from 100 liters of tap water.

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