Mycoplasma spp. in backyard poultry: Isolation, serology, and molecular evidence from southeastern Brazil

Avian mycoplasmosis affects commercial and backyard poultry, but its occurrence in subsistence flocks in Brazil remains poorly characterized. This pilot study investigated Mycoplasma spp. in 35 clinically healthy birds from five domestic species on 11 rural properties in southeastern Brazil. Tracheal swabs were cultured in Friis medium and isolates screened by genus-specific qPCR, followed by species-specific qPCR for M. gallisepticum , M. synoviae , and M. meleagridis . Sera from 25 chickens and two turkeys were tested with a commercial M. gallisepticum / M. synoviae ELISA. Presumptive growth occurred in 22/35 samples (62.9%; 95% CI, 46.3–76.8%). Of 64 selected colonies, 29 were confirmed as Mycoplasma spp. (45.3%; 95% CI, 33.7–57.4%). At least one confirmed isolate was obtained from 13/35 birds (37.1%; 95% CI, 23.2–53.7%) and 7/11 properties (63.6%; 95% CI, 35.4–84.8%). None of the isolates was identified as the three targeted species. Antibodies to M. gallisepticum and/or M. synoviae were detected in 18/27 birds (66.7%; 95% CI, 47.8–81.4%), all chickens (18/25; 72.0%; 95% CI, 52.4–85.7%); both turkeys were seronegative. The discrepancy between serological exposure and absence of molecular detection of classical pathogenic species may reflect previous exposure without active shedding or circulation of non-target Mycoplasma species. These findings support broader surveillance and molecular characterization of Mycoplasma in subsistence poultry at the domestic–wild bird interface.