High mortality in a commercial turkey flock associated with coinfection by <i>Pasteurella multocida</i> and <i>Mycoplasmoides</i> ( <i>Mycoplasma</i> ) <i>gallisepticum</i>

Six 11-wk-old, commercial, Broad-Breasted White, meat turkeys were submitted to the Turlock branch of the California Animal Health & Food Safety (CAHFS) laboratory for autopsy and diagnostic work-up. Clinical signs in the turkeys of the affected flock included depression, ruffled feathers, swollen periorbital areas, rales, and sneezing. A mortality of 50% (5,000 of 10,000) was reported at the time of case submission. Flock morbidity was 100% by 12 wk of age, and mortality eventually exceeded 90%. Fibrinous pleuropneumonia, airsacculitis, increased luminal mucoid exudate in the nasal cavities and tracheas, mottled and enlarged spleens, and hepatomegaly were the most remarkable gross findings. Microscopically, fibrinoheterophilic pneumonia and epicarditis with intralesional bacterial colonies, and necrotizing hepatitis and splenitis, were noted. <i>Mycoplasmoides</i> (<i>Mycoplasma</i>) <i>gallisepticum</i> (MG) was detected in tracheal and sinus pools by quantitative real-time PCR. Multilocus sequence analysis of the <i>mgc2</i> gene and IGSR segment of MG differentiated our strain from MG vaccine strains, but were similar to MG isolates detected previously in other commercial turkey operations in California. <i>Pasteurella multocida</i> was isolated from air sacs, lungs, tracheas, hearts, and livers, and classified as profile H<i>ha</i>I 0001, strain X-73, by restriction enzyme analysis DNA fingerprinting. Coinfection with <i>P. multocida</i> and MG in a susceptible flock resulted in rapid elevation of mortality and significant economic losses in this commercial meat turkey operation.