Occurrence: Worldwide, but more common in tropical areas of the world and in farms with multiage pullets. Coryza means head cold.
Age of bird: Mostly 15‑30 weeks, but has been seen in broiler age birds.
Species affected: Only chickens.
Cause: Haemophilus paragallinarum is a gram‑negative, polar‑staining, non‑motile bacterium, and appears as short rods or coccobacilli.
Coryza
A chronic disease caused by Haemophilus paragallinarum is a gram‑negative, polar‑staining, non‑motile bacterium, and appears as short rods or coccobacilli. Strong odor (rotten eggs) given off by the organism.
Fecal, aerosol.
Watery eyes, facial edema, diarrhea, lowered weight gain, anorexia, and high cull rate (20%) may be evident. Nasal discharge, swollen infraorbital sinus, labored 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, airsacculitis, and conjunctivitis may be evident.
Respiratory signs, odor and isolation of organisms are important. Serologic tests include agar gel precipitin and hemagglutination‑inhibition. It simulates many respiratory problems, fowl pox (FP), vitamin A deficiency, fowl cholera (FC), and mycoplasma infections.
Bacterin (containing serogroups A,B,C) 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.
A number of antibiotics can be used in the feed or water.
Old bird diseases occur more among free-range hens
Over the last two decades old bird diseases, such as Coryza, Blackhead and Pasteurelle multocida increasingly reared their ugly heads among free-range hens. These diseases barely occurred when laying hens were kept in cages.
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