Occurrence: Worldwide.
Species affected: All.
Age affected: All.
Causes: Small procaryotic microorganisms- Mycoplasma gallisepticumM. meleagridis. Spread through egg contact or contact with infected birds by aerosol.
Effects: Signs include nasal discharge, emaciation, increased condemnation, sneezing and coughing, swollen infraorbital sinus (above the eye), feed refusal, foaming of the eye and/or air sacculitis.