Infectious coryza occurs mainly in warm and tropical / sub-tropical climates in chickens of all ages. It is caused by a gram negative, non-motile bacterium- Hemophilus gallinarum.
- Causes of Infectious coryza >
- Effects of Infectious coryza >
- Diagnosis of Infectious coryza >
- Treatment & Control of Infectious coryza >
Causes of Infectious coryza
Strong odour (rotten eggs) given off by the organism. Water eyes, facial oedema, diarrhoea, anorexia and high cull rate (20%) may be evident. Nasal discharge, swollen infraorbital sinus, laboured breathing, drop in egg production and shell quality can occur.
Postmortem lesions
Oral or tracheal lesions, catarrhal inflammation of nasal passages and sinuses may be seen.
Congested lungs, facial swelling, swollen wattles, pneumonia, air sacculitis and conjunctivitis may be evident.
Effects of Infectious coryza
The organism gives off a strong odour of rotten eggs. Symptoms include watery eyes, facial oedema, diarrhoea, anorexia, and there may be a high cull rate (20%). Nasal discharge, swollen infraorbital sinus, laboured breathing, drop in egg production and poor shell quality can also occur.
Postmortem lesions
Oral or tracheal lesions, catarrhal inflammation of nasal passages and sinuses may be seen.
Congested lungs, facial swelling, swollen wattles, pneumonia, air sacculitis and conjunctivitis may be evident.
Diagnosis of Infectious coryza
Respiratory signs, odour and isolation of organisms are important. The organism is a polar-staining, facultative anaerobic gram-negative rod. Brain heart infusion and NAD-yields tiny dew-drop colonies. Serologic tests include agar gel precipitin and haemagglutination-inhibition.
It simulates many respiratory problems, fowl pox (FP), vitamin A deficiency, fowl cholera (FC) and mycoplasma infections.
Treatment & Control of Infectious coryza
Prevention
Bacterin at 10-12 and 16-18 weeks and one age per farm can help prevent the disease. Destroy all clinically ill birds to contain spread of the organism.
Live vaccine using homologous field strain can be given by water in tropical areas where bacterin is not effective.
Treatment
Administering bacterin at 8 and 16-18 weeks and keeping one age per farm can help prevent the disease. Treatment of all clinically ill birds will contribute to containing the spread of the organism.
