Occurrence: Mainly in warm and tropical / sub-tropical climates.   Species affected: Chickens.   Age affected: All ages.

Causes: Gram negative, non-motile bacterium- Hemophilus gallinarum.

Effects: 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.

Infectious coryza affects chickens of 15-30 weeks. It is more common in tropical humid areas and where multi-age pullet farms are kept. Coryza means head cold.

The causative agent, Hemophilus gallinarum is a gram-negative, polar-staining, non-motile bacterium and appears as short rods or coccobacilli.

Faecal, aerosol.

It is found in Southern US and Third World Countries (multi-age farms) and is common in backyard flocks. Several serotypes (A,B,C) make successful vaccination difficult.

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.

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.

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.

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.

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.

Back to "I" Health & Diseases page

Back to main Health & Diseases page