The science behind poultry aspergillosis
Author(s): Brajen Singh
Abstract: Fungal infections in poultry, though less prevalent than bacterial and viral diseases, are increasingly recognized as significant respiratory threats, with aspergillosis being the most common mycosis. The disease, primarily caused by Aspergillus fumigatus and A. flavus, arises from inhalation of spores found in contaminated litter, feed, hatcheries, or ventilation systems. Stress, poor ventilation, overcrowding, nutritional deficiencies, and immunosuppressive conditions increase susceptibility, particularly in young chicks, turkeys, and ducklings. The infection manifests in acute or chronic forms, depending on spore load and host immunity, and may affect the respiratory and nervous systems. Seasonality, environmental humidity, and housing practices strongly influence outbreaks, with higher prevalence during warm, damp conditions. While moldy substrates such as feed, feathers, and litter act as reservoirs, hatchery contamination remains a key source of infection. Clinical outcomes vary with immune status, co-infections, and environmental stressors, often leading to high mortality. Interestingly, certain Aspergillus species, such as A. niger and A. awamori, exhibit probiotic effects when used as dietary supplements, highlighting a paradoxical role of the genus in poultry health. Effective management requires strict biosecurity, proper nutrition, and improved housing practices.
