Potential for transmission of the finch strain of Mycoplasma gallisepticum between house finches and chickens.

Although Mycoplasma gallisepticum (MG) is established in house finch (Carpodacus mexicanus) populations in at least 33 states, the potential risk of MG introduction to domestic poultry by infected finches currently is unknown. The objectives of this study were to determine if chickens could be infected with the finch strain of MG via direct, across-wire, and proximity (across-room) contact with naturally infected house finches and to determine if house finches could be infected through direct contact with experimentally infected chickens. Chickens were infected with the finch strain of MG through direct contact with naturally infected house finches, a determined by seroconversion (80%), polymerase chain reaction (PCR) (20%), and culture of MG (30%). Clinical disease was not observed in infected chickens. Isolates from chickens were identified as the original finch strain by arbitrary primed PCR. Transmission required an extended period of direct contact (10 wk) with infected finches, and no evidence of MG infection was detected in chickens exposed to infected finches across wire or across the room. Evidence of contact transmission of MG from infected chickens to house finches was limited to positive serum plate agglutination results, and infection could not be confirmed by PCR or culture. Results suggest that minimal biosecurity measures that restrict direct contact between chickens and house finches should significantly reduce the potential for MG transmission between these species.