Infectious bronchitis (IB)
Infectious bronchitis (IB) is a highly contagious viral disease caused by the Infectious Bronchitis Virus (IBV). It primarily affects the respiratory system of chickens but can also impact the reproductive, renal, and circulatory systems. One notable effect of Infectious bronchitis disease is the “blue comb” phenomenon, which occurs due to hypoxia, or reduced oxygen levels in the blood, resulting from severe respiratory distress and poor oxygen exchange caused by inflammation and congestion in the trachea and air sacs.
Furthermore, IB-induced damage to the kidneys can lead to circulatory issues, which contribute to poor blood flow and cyanosis, characterized by a bluish discoloration in peripheral tissues such as the comb. The pathogenesis of the virus begins when it enters the chicken through inhalation or ingestion. Within 18 to 36 hours, the virus rapidly replicates in the epithelial cells, causing symptoms such as coughing, sneezing, and nasal discharge.
Severe inflammation in the respiratory tract hinders oxygen delivery, while systemic effects of the infection, such as dehydration and electrolyte imbalances from renal dysfunction, worsen circulatory deficiencies. Studies have shown that outbreaks of IB can increase mortality rates in stressed flocks, particularly when secondary bacterial infections occur. Therefore, early diagnosis and management are crucial to preventing severe outcomes, including the blue comb phenomenon.