Evaluation of Treatment of Conjunctivitis Associated with Mycoplasma gallisepticum in House Finches ( Carpodacus mexicanus )

Thirty-seven house finches (Carpodacus mexicanus) with conjunctivitis were admitted to a rehabilitation center. Six (35%) of 17 conjunctival swab samples collected before treatment began were positive on culture for Mycoplasma gallisepticum. All birds were treated with cipro­ f10xacin hydrochloride ophthalmic solution (one drop in each eye [OU] q 12h) for 5 to 7 days and tylosin tartrate in water (l mg/ml) as the sole source of drinking water for 21 to 77 days. Con­ junctivitis was resolved in all birds after therapy was completed (60 to 177 days). Conjunctival swab samples from all birds collected after treatment and submitted for culture were negative for M. gallisepticum. Two (11 %) of the 18 conjunctival swab samples collected after treatment were positive for M. gallisepticwn by polymerase chain reaction (PCR). Serum samples from 2 (5.4%) other of the 37 birds were antibody positive for M. gallisepticum by serum plate agglutination; serum samples from these two birds were antibody negative when retested 22 days later. No gross lesions were found at necropsy in 16 house finches that had been treated, including the birds that tested positive by PCR or serum plate agglutination. Tissue samples of conjunctiva, choanae, in­ fraorbital sinus, trachea, lungs, air sacs, and reproductive organs collected at necropsy were negative for mycoplasma by culture (n = 16) and PCR (n = 15). We did not tind evidence of M. gallisepticum infection in house finches after treatment with tylosin tartrate administered orally and ciprofloxacin hydrochloride ophthalmic solution applied topically.