CRD- Incurable disease in Chicken, being cautious is the only cure

Chronic respiratory disease is the highly contagious respiratory disease Characterised by chronic but mild respiratory disease of adult chickens and air sac disease in young birds.

All species of birds of all ages are susceptible to chronic mycoplasma infection.
Can it spread from chicken to chicken?

Yes, chicken get infected via transovarian or by direct contact with birds, exudates, aerosols airborne dust and feathers and to a lesser extent fomites.


1.Stunted growth and reduced feed efficiency.

2.Respiratory symptoms: coughing, sneezing and nasal discharge.

3.Eye problems, conjunctivitis, periorbital swelling and inflammation/swelling and darkening around the face, beak, wattle and head.

4.Open mouth breathing, gurgling throat sounds/respiratory rales and sneezing.

Mycoplasma, gallisepticum

Gross Lesions:

  1. Airsacculitis: Cloudy appearance of the air-sacs.

2. Fibrinous pericarditis and perihepatitis

3. Catarrhal inflammation of nasal passages, sinuses, trachea and bronchi.

4. Congested trachea mucopurulent material in the lumen


1.Hatch stock, free of mycoplasma infection.

2.Hygiene and all-in/all-out production

3.Increased ventilation without drafts reduces the spread of severity of CRD.

It is difficult to prevent infections caused by Mycoplasma gallisepticum because the disease is transmitted by egg and any new birds must be free of the disease. Vaccinations have not proven to be a successful preventative measure because CRD is so often complicated by underlying diseases. Careful management strategies that minimise stress and the ability to determine the stage of CRD are important preventative measures in the treatment and long term prevention of Mycoplasma gallisepticum infections.


History, Clinical signs and lesions.

Serology, isolation and identification of orgasm


Antibiotic is useful for treatment (Tetracycline, Doxycycline, Tylosinetartarate) as per recommended doses.

Director of research, GADVASU

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