Chronic Respiratory

Chronic respiratory disease (CRD) is one of the most common respiratory diseases occurring in poultry. The disease occurs when birds infected with Mycoplasma gallisepticum are stressed. The subsequent invasion by secondary bacteria causes the major damage to the bird.

CRD is the most prevalent of the so-called ‘stress diseases’. Mycoplasma gallisepticummay be present in the tissues of healthy birds (carrier birds). Outbreaks occur most frequently when the flock's immunity is lowered either during times of stress - often caused by moving, chilling, vaccinating, beak trimming, deworming, poor ventilation, damp litter and ammonia build-up or in the presence of other diseases. Transmission may occur even in flocks that appear to be perfectly healthy.

Egg transmission is very important as it is the means by which the disease perpetuates itself. The disease is airborne (aerosol), Carrier birds, Visitors and generally rapid, but it does not travel distances. Characteristic symptoms for CRD are abnormal respiratory sound, sneezing, coughing and gasping. The organism is quite sensitive to common disinfectant. Line of treatment for CRD is Tylosin phosphate, tylosintartarate or tiamutin.