Avian diseases refer to illnesses that affect birds, including both wild and domesticated species. These diseases can be caused by various pathogens such as viruses, bacteria, fungi, and parasites. Common avian diseases include avian influenza, Newcastle disease, and psittacosis, which can lead to significant health issues and even death in affected birds. Preventing avian diseases involves proper management practices, including vaccination, biosecurity measures, and regular health monitoring. It is essential for bird owners and poultry farmers to be aware of the signs of illness and to seek veterinary care when necessary to protect their flocks and prevent the spread of diseases.