TRANSMISSIBILITY OF LIVE MYCOPLASMA-GALLISEPTICUM VACCINE STRAIN-TS-11 AND STRAIN-6 85 FROM VACCINATED LAYER PULLETS TO SENTINEL POULTRY/

In separate trials, layer pullers were vaccinated with Mycoplasma gall isepticum (MG) strain 6/85 or strain ts-11 commercially produced live vaccines. For a 15-wk postvaccination (PV) period, vaccinates were com mingled with unvaccinated pullers and were in indirect contact with se ntinel groups of pullers, broiler breeders, turkey breeders, or meat t urkeys in adjoining pens. Infectivity and transmissibility of vaccine strains were determined by tracheal culture and serology at 1 wk follo wed by 3-wk intervals PV. Strain 6/85 was recovered from 0%-20% of vac cinates, but not from commingled pullets or sentinel birds. Strain ts- ll was recovered from 60%-90% of vaccinates and 0%-40% of commingled p ullers but not from any of the sentinel birds. No birds in the 6/85 va ccine trial tested positive for MG antibodies by serology. MG enzyme-l inked immunosorbent assays detected positive responses in ts-11 vaccin ates (range = 10%-70%) at 42, 63, 84, and 105 days PV, and commingled pullets (10%) at 84 and 105 days PV MG serum plate agglutination tests detected positive responses in 90% and 20% of ts-11 vaccinates at 42 and 105 days PV, respectively, and commingled pullers (10%) at day 42 PV. Clinical signs, morbidity, or mortality suggestive of pathogenic M G infection were not observed in any bird during either trial, and no gross lesions were observed at necropsy. Random amplified polymorphic DNA analysis was capable of distinguishing each of the vaccinal strain s 6/85 and ts-11 from each other by their distinct DNA banding pattern s.