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Importance of Chicken Infectious Bronchitis Virus: Q&A

Updated September 28, 2020

Tamer Sharafeldin

Assistant Professor, Veterinary Pathologist

Questions and Answers

Several chickens in chicken coup. Some are resting lethargically.

We usually hear the term IBV said by veterinarians and poultry professionals, what is that?

Infectious bronchitis virus (IBV) is a coronavirus that infects chicken flocks, causing respiratory disease. Some IBV isolates can result in a kidney disease (nephritis). Drop of egg production in laying hens is an important sign for IBV infection.

You just said a coronavirus, is it like COVID-19?

No, it is not. Coronaviridae is a big virus family with many viruses. Some of them cause enteric diseases and some them induce respiratory diseases with varying magnitudes. IBV does not infect humans or other mammals. IBV was the first coronavirus discovered and typed in the 1930s in North Dakota before the discovery of human coronaviruses.

Why is IBV an important disease?

Because the virus is highly contagious and can easily transmit among birds in the flock in a short time. The virus does not produce a lethal respiratory disease but a secondary bacterial infection or concurrent viral respiratory infection in addition to some environmental stressors (low temperature) can result in high mortality. Additionally, IBV is a big concern for the layer industry and owners of small laying flocks as the virus causes a drop in egg production.

When I need to suspect that I have IBV in my flock?

Chickens infected with IBV can display respiratory signs (coughing, gasping, weakness, huddling and/or nasal ocular secretions) which can be worse if there is a secondary bacterial infection. IBV is the hidden criminal behind the obvious secondary bacterial infection. The primary IBV infection is the main starter of the respiratory illness. On many occasions, respiratory illness is attributed to secondary bacteria and IBV is not recognized although it is the main initiator. The virus affects the upper respiratory tract and air sacs. Please note that some IBV strains can result in diarrhea due to kidney disease leading to high mortality in young chickens (1-3 weeks). If your laying hens display drop in egg production, IBV should be on the top of your list.

Would you elaborate more about IBV egg drop?

IBV can affect the reproductive tract of chicken hens at two levels. First, it infects young pullets at 1-3 weeks of age resulting in destruction of the developing oviduct. Pullets will reach sexual maturity because the ovary is functional, but they will not lay eggs because of the destroyed oviduct (which usually looks like a thin-walled cyst with watery secretions). The flock hardly exceeds 50% egg production, and this is a significant economic loss that is not discovered but after the age of laying after putting a huge investment in the growing pullets. This false layer syndrome is a big concern for egg producers. The second level when IBV affects laying hens. Infection will result in a gradual drop (nearly 10%-20%) in egg production which will gradually resume after birds develop immunity.

How can we protect our flocks from IBV?

 Vaccination is the best-known solution to protect against IBV. The fact that there are multiple IBV strains that are not cross protective should be considered in designing the vaccination program. Strict biosecurity measures are the key for safe profitable production. Vaccination may be challenging for small flocks, but it is not impossible.

Can we diagnose IBV? and what can we do for a reliable IBV diagnosis?

Clinical disease displayed by birds may be suggestive for IBV infection. Confirmatory diagnosis requires virus isolation, detection and/or typing using molecular genetic methods. SDSU Animal Disease Research and Diagnostic Laboratory (ADRDL) in Brookings, SD will offer comprehensive diagnostics for the identification and typing of IBV. This will help the layer industry and small flock owners develop effective protection plans.

Related Topics

Poultry, Animal Health