MOLECULAR EPIDEMIOLOGIC INVESTIGATIONS OF MYCOPLASMA-GALLISEPTICUM CONJUNCTIVITIS IN SONGBIRDS BY RANDOM AMPLIFIED POLYMORPHIC DNA ANALYSES

An ongoing outbreak of conjunctivitis in free-ranging house finches (C arpodacus mexicanus) began in 1994 in the eastern United States. Bacte rial organisms identified as Mycoplasma gallisepticum (MG) were isolat ed from lesions of infected birds. MG was also isolated from a blue ja y (Cyanocitta cristata) that contracted conjunctivitis after being hou sed in a cage previously occupied by house finches with conjunctivitis , and from free-ranging American goldfinches (Carduelis tristis) in No rth Carolina in 1996. To investigate the molecular epidemiology of thi s outbreak, we produced DNA fingerprints of MG isolates by random ampl ification of polymorphic DNA (RAPD). We compared MG isolates from song birds examined from 1994 through 1996 in 11 states, representing three host species, with vaccine and reference strains and with contemporar y MG isolates from commercial poultry. All MG isolates from songbirds had RAPD banding patterns identical to each other but different from o ther strains and isolates tested. These results indicate that the outb reak of MG in songbirds is caused by the same strain, which suggests a single source; the outbreak is not caused by the vaccine or reference strains analyzed; and MG infection has not been shared between songbi rds and commercial poultry.