Avian infectious bronchitis

Avian Infectious Bronchitis

Avian Infectious Bronchitis (IB) is a highly contagious viral disease that affects chickens. It is caused by the Infectious bronchitis virus (IBV), which is a member of the Coronaviridae family. The disease primarily affects the respiratory tract, but it can also impact the reproductive and renal systems, leading to significant economic losses in the poultry industry.

Etiology

The causative agent, Infectious bronchitis virus, is an enveloped virus with a single-stranded, positive-sense RNA genome. It is characterized by its ability to rapidly mutate, leading to the emergence of numerous serotypes and variants. This genetic diversity complicates the development of effective vaccines and control measures.

Transmission

IBV is transmitted through direct contact with infected birds or indirectly via contaminated equipment, feed, water, and personnel. The virus is shed in respiratory secretions, feces, and eggs, facilitating its spread within and between flocks.

Clinical Signs

The clinical presentation of avian infectious bronchitis varies depending on the age of the birds, the virulence of the virus strain, and the presence of secondary infections. Common signs include:

• Respiratory distress (coughing, sneezing, and nasal discharge)
• Decreased egg production and poor egg quality in laying hens
• Nephritis and increased mortality in severe cases

Diagnosis

Diagnosis of IB is based on clinical signs, post-mortem examination, and laboratory tests. Polymerase chain reaction (PCR) and virus isolation are commonly used to detect and identify IBV. Serological tests, such as enzyme-linked immunosorbent assay (ELISA), can also be employed to assess antibody levels in flocks.

Prevention and Control

Effective control of avian infectious bronchitis relies on a combination of biosecurity measures and vaccination. Biosecurity practices include:

• Limiting access to poultry houses
• Regular cleaning and disinfection
• Controlling movement of personnel and equipment

Vaccination is a critical component of IB control. Live attenuated and inactivated vaccines are available, but their efficacy can be limited by the antigenic diversity of IBV strains. Vaccination programs should be tailored to the specific needs of each flock, considering local virus strains and risk factors.

Economic Impact

IB can cause significant economic losses due to decreased egg production, poor egg quality, increased mortality, and costs associated with vaccination and biosecurity measures. The disease poses a continuous challenge to the poultry industry worldwide.

Also see

• Newcastle disease
• Avian influenza
• Poultry farming
• Viral diseases of poultry