English abstract
Mycoplasma gallisepticum (Mg) is an etiologic agent of chronic respiratory disease (CRD) in poultry. The disease is characterized by respiratory distress, sneezing, sinusitis, and conjunctivitis. In the present study, 551 sera (local = 327, exotic = 224) and 226 egg-yolk samples (local = 111, exotic =115) were collected from broilers and layers respectively. The samples were tested for the presence of antibodies using an antigen specific MgELISA (Enzyme Linked Immunosorbant Assay) and the results were compared to a routinely used MgSPA (Serum Plate Agglutination) test. The results demonstrated that 27.2% of sera and 50.9% of egg yolk samples were found to have specific antibodies for Mg. Further analysis revealed that the local breed had a higher percentage of seropositive broilers and positive egg-yolk samples in layers. The highest percentage of seropositive chickens was recorded in the local broilers (34.8%) when compared to exotic broilers (1.8%). Similarly, the results of egg yolk samples demonstrated that the local layers had a higher number of positive samples (21.6%) than the exotic layers (3.2%). There was a significant difference (p<0.05) in seropositivity between broilers and layers of local and of exotic breeds. Based on the results of the MgELISA and the MgSPA tests, it was determined that the MgSPA test gave 6.3% false positives and 1.4% false negative results. When the same sera were tested with an antigen specific MsELISA test, it was found that 61.3% of the false positive samples were due to infection with Mycoplasma synoviae (Ms) which indicates that most cross reactions seem to be caused by infections with Ms.
