Avian Mycoplasmosis is a chronic respiratory disease which causes very low mortality but it decreases egg production and causes carcass condemnation. A cross sectional study was conducted from September 2010 to October 2012 to identify the potential risk factors for Mycoplasma gallisepticum (Mg) seroprevalence in commercial chicken production in Chittagong area, Bangladesh. A total of 5589 serum samples were collected from one hundred chicken flocks of different production systems (commercial

more »

... yer, broiler and layer breeder). Antibody against Mycoplasma gallisepticum was determined by commercial indirect Enzyme Linked Immunosorbent Assay (ELISA) kit. A multivariable logistic regression model was designed to evaluate the risk factors for Mg seroprevalence. The ELISA test results demonstrated that 32% of the birds were seropositive to Mg antibodies in the study area. A multivariable logistic regression model identified a strong effect of 'age' on the Mg antibody level where birds of more than 53 weeks of age showed the greatest risk of being positive for Mg (OR 419.27, 95% CI 294.67-596.54, P<0.0001) compared to birds less than 16 weeks of age. Moreover, monsoon season (OR 2.962, 95% CI 2.24-3.92, P<0.0001), male birds (OR 1.192, 95% CI 1.03-1.38, P=0.0196) and Commercial layer type of production system (OR 2.641, 95% CI 2.17-3.22, P<0.0001) were factors found to be associated the risk of attracting Mg in chickens.