Risk factors for Mycoplasma gallisepticum seropositivity in backyard poultry flocks in the vicinity of wintering site for migratory birds in Southern Brazil

Mycoplasma gallisepticum (MG) is an important pathogen that affects domestic and wild birds, causing severe respiratory disease. The lack of biosecurity on backyard poultry flocks can be a source of MG infection. The aim of this study was to evaluate the frequency of anti-MG antibodies and associated risk factors in backyard poultry flocks in one of the main wintering sites for migratory wild birds in Brazil, the Parque Nacional da Lagoa do Peixe (PNLP). Three hundred and ninety-one adult and clinically healthy birds from 48 household flocks were randomly selected for blood collection and further detection of antibodies against MG by ELISA. A questionnaire was used to evaluate potential risk factors. Twenty-eight households (58.3%) had at least one bird that was seropositive to MG. Seropositivity was significantly associated with bird confinement (PR = 3.40, 95% CI: 1.93 – 5.99) and with interaction between “poultry/egg exchange and neighbors have poultry” (PR = 2.16, 95% CI: 1.24 – 3.76). This is the first study that evaluates the risk factors associated with anti-MG antibodies in backyard poultry flocks. The results demonstrate the importance of backyard poultry in households located in wintering sites for migratory birds as potential reservoirs and sources of infection of diseases that can affect both commercial poultry and migratory wild birds that come to the region.