How pathogens affect the trachea in poultry

The trachea is an important defense line in the respiratory system and whole body system. The essential weapons of the trachea are cilia and mucosal secretions any fault in behavior of the weapons due to escape of the organisms and affect the body.
How do pathogens affect the trachea??
1-ND Newcastle disease: this disease due to cilia less of the trachea after 2 days of infection.
2-IB infection bronchitis: this virus affected the subepithelial cells of the trachea and due to edema in these cells and slough of the epithelial cells.
3-MG mycoplasma gallisepticum: MG after enter the trachea it will secrete the metabolic materials due to necrosis of the cilia and due to cilia less so the MG enter to the respiratory system.
4-ILT infection Laryngotracheitis: the proliferation of this virus and aggregate of viruses copy in the vacuoles in cytoplasm of the tracheas cells due to death of the tracheas cell by apoptosis and slough of the epithelial cells.
5- The important pathogens affected the trachea and whole respiratory system is
ND+IB+MG:
When these diseases incorporated to affect the trachea and this allied happened in the poultry field when we the live vaccines of ND+IB applied by spray and the broiler affected by MG (CRD) I saw in the upper trachea mucosal secretions and in the bronchi I saw the fibrinous plugs due to mortem of birds by asphyxia.
How we can evade this problem:
We must not applied the two live vaccines simultaneously especially which is used for the respiratory system protection (there must be intervals of 15 days between 2 applied).
Monitoring of the MG in the broiler breeder.
Don’t vaccinate the ill birds (and we must always remember that the vaccine for protection and the time of vaccine isn’t imperative).
Good applied for the vaccine because the take (reaction) of abused vaccine is worst than infection in itself.
Don’t vaccine the broilers in age up 25 days old because it will due to carcass contamination in the slaughter house.
Thank you
(It is my pleasure to be one from the engormix family).