Infectious coryza In Poultry

Infectious coryza is a sudden and severe respiratory disease of chickens.

The disease is characterized by swelling of the face and discharges from the eyes and nostrils . The greatest economic losses occur from poor growth in growing birds, and a marked drop in egg production (10-40%) in layers. The disease is extremely common both in broilers and layers. Chickens of all ages are susceptible, but older birds suffer more severely.

Cause

A bacterium called Haemophilus paragallinarum. It is a delicate bacterium and dies quickly outside the bird .

Survival outside the body under fa rm conditions is not more than 48 hours.

Spread

I. The infection can be spread by drinking water contaminated with discharges from the nose.

2. Infection can also be spread over a short distance by t he air.

3. Lateral spread occurs readily by direct contact.

4. Spread between cages with nipple drinkers occurs more slowly.

Symptoms

I. The first symptoms include sneezing, mucus-like discharge from the openings of the nose and eyes, and swelling on the face . In severe cases, marked conjunctivitis (inflammation of conjunctiva) with closed eyes, swollen wattles, and difficulty in breathing can be seen.

2. Feed and water consumption is usually decreased. This results in a drop in egg production, or an increase in the culling (removal) of inferior, weaker, and worthless birds.

Postmortem Findings

I. Swelling of the face and wattle due to accumulation of fluid under the skin is marked .

2. There is inflammation of the nasal passages and the space present below the eye.

3. The upper trachea may be involved but the lungs and airsacs are affected only in chronic, complicated

cases.

Diagnosis

I. Marked swelling on the face and discharges from the eyes and nostrils are quite diagnostic of the disease.

2. Postmortem findings are helpful in making the diagnosis.

Treatment

Various sulpha drugs and antibiotics are useful in treating the disease. The combination of sulpha drug trimethoprim, tetracyclines, and enrofloxacin may be used. Erythromycin and oxytetracycline are also commonly used antibiotics.

Control

I. Improved management practices, such as culling of birds, good sanitation, traffic control, and avoiding birds of multiple ages help in breaking the disease cycle. Keep only birds of the same age on the farm.

2. Because of the difficulty of controlling infectious coryza by sanitary measures, drug therapy and/or vaccination are used. Vaccination with a killed virus can protect chickens against the disease.

3. To eliminate the agent from the farm, it is necessary to dispose of the infected or recovered birds because such birds remain as a reservoir of the bacterial agent. After cleaning and disinfection, the farm should be allowed to remain vacant for 2-3 weeks before restocking with clean birds.