Whether the virus persists in recovered turkey flocks is also unknown. TRT virus has been detected in oviduct tissue, but no proof of egg borne transmission has been shown. The virus is transmitted by direct contact between infected and susceptible birds and is believed to be transmitted by indirect contact including exposure to aerosol droplets or to virus-contaminated boots, clothing or equipment. Airborne transmission from farm to farm is widely suspected but unproven. The clinical signs are extremely variable and seem to depend on the age, gender, concurrent infections, and environmental factors.
Silent infections are possible.
Listlessness, huddling, coughing, sneezing, rales, swollen sinuses, nasal discharge and stained shoulder feathers may be observed. As clinical signs subside birds may begin to die. FSIS condemnation rates are usually elevated if turkeys are infected within two weeks of processing. There are few striking lesions because the disease is mild. There may be mild tracheitis, airsacculitis, lung congestion and inflammation of the turbinates.