Characteristics of infectious coryza in chicken
It is a usually acute, sometimes chronic, highly infectious disease of chickens, occasionally pheasants and guinea-fowl, characterised by catarrhal inflammation of the upper respiratory tract, especially nasal and sinus mucosae.
Causes and Transmission
Chronically ill or healthy carrier birds are the reservoir of infection. Chickens of all ages are susceptible, but susceptibility increases with age. The incubation period is 1–3 days, and the disease duration is usually 2–3 wk. Under field conditions, the duration may be longer in the presence of concurrent diseases.
Infected flocks are a constant threat to uninfected flocks. Transmission is by direct contact, airborne droplets, and contamination of drinking water. Management has essentially eradicated infectious coryza from many commercial poultry establishments. Commercial farms that have multiple-age flocks tend to perpetuate the disease. Egg transmission does not occur
Signs and sypmtoms
In acute cases, lesions may be limited to the infraorbital sinuses. There is a copious, tenacious, grayish, semifluid exudate. As the disease becomes chronic or other pathogens become involved, the sinus exudate may become consolidated and turn yellowish. Other lesions may include conjunctivitis, tracheitis, bronchitis, and airsacculitis, particularly if other pathogens are involved
Sulphonamides, tylosin, erythromycin. Flouroquinolones should be used as directed by the manufacturer.
Prevention is the most effective method of control. Farms with good vaccination and isolation methods are the best way to avoid infectious coryza. Infected birds should be separated and treated. Erythromycin and oxytetracycline are usually beneficial. sulfonamides, sulfonamide-trimethoprim, and other combinations have been successful.