Sero-prevalence and Associated Factors of Major Respiratory Diseases (Avian Influenza, Newcastle Disease, Infectious Bronchitis, and Mycoplasma Gallisepticum) in Layers Farms in Dakar and Thiès, Senegal

Purpose: This study aimed to identify associated factors and the prevalence of major avian respiratory diseases, including Mycoplasma gallisepticum, Influenza H9, Infectious Bronchitis (IB), and Newcastle disease in poultry farms in the Dakar and Thiès regions of Senegal. Methodology:A cross-sectional observational study was conducted on purposively selected farms with over 1000 birds exhibiting respiratory symptoms. Blood samples (400) were collected for serological analysis, and post-mortem examinations were performed to assess disease prevalence. Additionally, data on biosecurity, vaccination, medication practices, general management, and farm infrastructure were obtained through direct observation. Student t-tests were used to analyze the association between different farming practices and respiratory infections. Findings: The results indicated that proximity to neighboring farms, non-compliant buildings, mixed-age groups, and lack of farmer training were associated with respiratory diseases in the surveyed farms. Serological analysis revealed a high prevalence of Mycoplasma gallisepticum and Influenza H9, each detected in 50% of the farms. Infectious Bronchitis was found in 40% of the farms, while Newcastle disease was detected in 35%. Co-infections were common, with the combination of H9 influenza and Mycoplasma gallisepticum being the most prevalent (33%). Unique Contribution to Theory, Practice and Policy: The study emphasizes the need for targeted interventions, including improved biosecurity measures, vaccination strategies, and farmer training, to control respiratory infections. Strengthening biosecurity protocols and enhancing farmer education will help reduce disease.