Characteristics of infectious coryza in chicken
Infections Coryza is usually acute and sometimes chronic, highly infectious disease of chickens, occasionally pheasants and guinea-fowl. Infectious Coryza is characterised by catarrhal inflammation of the upper respiratory tract, especially nasal and sinus mucosae.
Infectious Coryza is caused by the bacterium Haemophilus paragallinarum and is seen in many countries especially in multi-age farms that are never depopulated. Morbidity is high but mortality low if uncomplicated, although it may be up to 20%.
The route of infection is conjunctival or nasal with an incubation period of 1-3 days followed by rapid onset of the disease over a 2-3 day period with the whole flock affected within 10 days. This results in increased culling. Carriers are important with transmission via exudates and by direct contact. It is not egg-transmitted.
The bacterium survives 2-3 days outside the bird but is easily killed by heat, drying and disinfectants. Intercurrent respiratory viral and bacterial infections are predisposing factors.
Infectious coryza is a serious bacterial disease of chickens which affects respiratory system and it is manifested by inflammation of the area below the eye, nasal discharge and sneezing. The disease is found all over the world causing high economic losses. Economic loss is due to stumping off and reduction of egg production in case of laying chickens. The disease was discovered early 1930s by considering clinical signs.
Causes and Transmission
Signs and symptoms
- Facial swelling.
- Purulent ocular and nasal discharge.
- Swollen wattles.
- Loss in condition.
- Drop in egg production of 10-40%.
- Catarrhal inflammation of nasal passages and sinuses.
- Eye-lid adherence.
- Caseous material in conjunctiva/sinus.
A presumptive diagnosis may be made on signs, lesions, identification of the bacteria in a Gram-stained smear from sinus. Confirmation is by isolation and identification – requires X (Haematin) and V (NAD) factors, preferably in raised CO2 such as a candle jar. Serology: HI, DID, agglutination and IF have all been used but are not routine.
Differentiate from Mycoplasmosis, respiratory viruses, chronic or localised pasteurellosis and vitamin A deficiency.
More Tips of Poultry Disease
Factors Contributing to Disease in poultry
- Poor-quality food and water
- Poor hygiene and inadequate cleaning programme
- Leaking water bowls
- Rat and fly problems
- Overcrowding of chicks
- Chickens of mixed ages reared together
- No security measures to prevent people and animals from entering the chicken house.
- Too hot or too cold conditions
- Wet litter
- Dusty bedding
- High build up of chicken droppings
- No air circulation
- Sharp wires in the cages
- Young chickens
- Weak second-grade chickens
- Chickens affected with other diseases
- Poor condition as a result of underfeeding
- No vaccination