ElsitioAvicola.com - Avicultura, Salud Aviar, Bienestar, Enfermedades, Noticias Avícolas, Artículos, Fotos Avícolas

ThePoultrySite Quick Disease Guide

Use the above box to quickly switch to another disease
Contents of Quick Disease Guide

Infectious Bronchitis, IB Egg-layers

Extracted From:
A Pocket Guide to
Poultry Health
Order me a copy
By Paul McMullin
© 2004
Click Here to
Order Your Copy


A Coronavirus infection of chickens, with much antigenic variation. The condition has a morbidity of 10-100% and mortality of 0-1%. Infection is via the conjunctiva or upper respiratory tract. There is rapid spread by contact, fomites or aerosol. A few birds are carriers up to 49 days post infection.

The virus is moderately resistant and may survive 4 weeks in premises. Poor ventilation and high density are predisposing factors.


  • Drop in egg production (20-50%).
  • Soft-shelled eggs.
  • Rough shells.
  • Loss of internal egg quality.
  • Coughing, sneezing.
  • Rales may or may not be present.

Post-mortem lesions

  • Follicles flaccid.
  • Yolk in peritoneal cavity (non-specific).


3-5 passages in CE, HA-, typical lesions, FA. Serology: HI, SN, Elisa, DID. Differentiate from Egg Drop Syndrome, EDS­76.


Sodium salicylate 1gm/litre (acute phase) where permitted - antibiotics to control secondary colibacillosis (q.v.).


Live vaccines of appropriate sero-type and attenuation, although reactions can occur depending on prior immunity, virulence, particle size (if sprayed) and general health status. Maternal immunity provides protection for 2-3 weeks. Humoral immunity appears 10-14 days post vaccination. Local immunity is the first line of defence. Cell-mediated immunity may also be important.

Figure 22. Flaccid ovarian follicles in a broiler parent chicken undergoing challenge with Infectious Bronchitis virus.

¿Quién Está En Línea?



No se pierda...

Probiotics In Poultry - 5m Books