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 Post subject: Coryza
PostPosted: Sun Apr 21, 2013 7:21 am 
Wise Wyandotte
Wise Wyandotte

Joined: Fri Feb 15, 2008 11:58 am
Posts: 4234
Location: Plainland, SEQ

Infectious coryza is a specific respiratory disease in chickens that occurs most often in semi-mature or adult birds. Infection may result in a slow-spreading, chronic disease that affects only a small number of birds at one time, or in a rapid spreading disease with a higher percentage of birds being affected. The occurrence of infectious coryza is not widespread and the incidence is relatively low.

The disease is caused by a bacterium known as Hemophilus gallinarum. Outbreaks usually result from the introduction of infected or carrier birds into a flock. Transmission of the infection occurs by direct contact, airborne infection by dust or respiratory discharge droplets and drinking water contaminated by infective nasal exudate.

Susceptible birds usually develop symptoms within three days after exposure to the disease. Recovered individuals may appear normal but remain carriers of the organism for long periods. Once a flock is infected, all birds must be considered as carriers.

The most characteristic symptoms of infectious coryza include edematous swelling of the face around the eyes and wattles, nasal discharge and swollen sinuses. Watery discharge from the eyes frequently results in the lids adhering together. Vision may be affected because of the swelling.

The disease results in a decrease in feed and water consumption and an increase in the number of cull birds. An adverse effect on egg production usually occurs in proportion to the number of affected birds.

Diagnosis can be confirmed only by isolation and identification of the causative organism. The organism, Hemophilus gallinarum, is extremely fastidious and often difficult to isolate.
Prevention is the only sound approach in controlling infectious coryza.

It usually can be prevented by management programs that eliminate contact between susceptible and infected birds. It requires only separating affected or carrier birds from the susceptible population. In order to prevent the infection, introduce started or adult birds only from sources known to be free of the infection.

If infection occurs, complete depopulation followed by thorough cleaning/disinfecting is the only means for eliminating the disease.
A number of drugs are effective for treating the symptoms of the disease although the disease is never completely eliminated. Sulfadimethoxine or sulfathiazole in the feed or water or erythromycin administered in the drinking water can reduce the symptoms of this disease.




Haemophilus paragallinarum (gram negative, catalase negative bacterial rod).

Coryza is a term used for any disease that causes sinusitis and running eyes. The list is long and included infectious Bronchitis, Vitamin A deficiency (Roup), Infectious Coryza, Mycoplasma, and physical irritation (ammonia, dust, excessive moisture, etc)

Species affected:
Chickens, pheasants, and guinea fowl are the most common species affected by this disease
It is also common in game chicken flocks

Culture growth requirements
Requires V factor (nicotinamide adenine dinucleotide) for growth in culture medium. Satellitism with Staph nurse colonies.

It is a serious avian respiratory disease.
Primarily affects chickens (especially pullets and layers, occasionally broilers).
Susceptibility increases with age.

Direct contact, aerosolization, and ingestion (drinking water). Reservoir = chronically ill or healthy carrier birds.
Coryza is primarily transmitted by direct bird-to-bird contact. This can be from infected birds brought into the flock as well as from birds which recover from the disease which remain carriers of the organism and may shed intermittently throughout their lives.
Birds risk exposure at poultry shows, bird swaps, and live-bird sales.
Inapparent infected adult birds added into a flock are a common source for outbreaks.
Within a flock, inhalation of airborne respiratory droplets, and contamination of feed and/or water are common modes of spread.

Clinical signs:
Malodorous mucoid nasal discharge, sneezing, conjunctivitis, facial swelling, decreased egg production, and diarrhea.
Mild form (young Leghorns or broilers): Depression, serous nasal discharge, occasional slight facial swelling).
Severe form (young adult Leghorns or heavy breeders): Severe swelling of one or both infraorbital sinuses with edema of surrounding tissue (may close one or both eyes). Especially in males, may see edema extending to the intermandibular space and wattles.

Clinical Signs:
Continual nasal discharge
Swelling around the face
Labored breathing and rales (rattles, an abnormal breathing sound)
Conjunctivitis, eyelids are irritated and may be stuck together
Smelly nasal discharge (mild form)
Decreased egg production
Diarrhea, and growing birds may become stunted
Depression (mild form)
Occasional slight facial swelling (mild form only)
Severe facial sinus swelling (severe form only)
Swollen eye with discharge (severe form only)
Swollen mandible and wattle area (severe form only)
Birds often show stained wings where they repeatedly wipe their eyes

This disease usually occurs when there is cold weather, (change of seasons is a high risk time) dusty conditions and in high pollen seasons

Mortality from coryza is usually low, but infections can decrease egg production and increase the incidence and/or severity of other diseases. Mortality can be as high as 50 percent, but is usually no more than 20 percent. The clinical disease can last from a few days to 2-3 months, depending on the virulence of the pathogen and the existence of other infections such as mycoplasmosis

Copious, tenacious, grayish, semifluid exudate in the sinuses (may become consolidated/yellowish with time and secondary infection).

Clinical signs and culture conditions (see above). Antibodies are detectable 2-3 weeks after infection (agglutination, HI, etc).
DDx: Fowl cholera especially. Also mycoplasmosis, laryngotracheitis, Newcastle, infectious bronchitis, avian influenza, and vitamin A deficiency.

Water soluble antibiotics or antibacterials can be used. Sulfadimethoxine (Albon, Di-MethoxTM) is the preferred treatment. If it is not available, or not effective, sulfamethazine (Sulfa-Max�, SulfaSureTM), erythromycin (gallimycin), or tetracycline (Aureomycin) can be used as alternative treatments. Sulfa drugs are not FDA approved for pullets older than 14 weeks of age or for commercial layer hens. While antibiotics can be effective in reducing clinical disease, they do not eliminate carrier birds.
Antibiotic Name = Tetravet 100 (recommended by Camden Poultry Centre)
Erythromycin, oxytetracycline, fluoroquinolones, macrolides. Use medication in water while waiting for medicated feed to be formulated.
May see relapses when discontinue antibiotics.
Antibiotics are used to cure this disease, however recovered birds remain carriers and will become continually reinfected. Some breeds and strains of chickens seem to be more susceptible than others.
Symptoms have a rapid onset usually lasting 1-3 days
Bacterial diseases

You can put warm, hot compresses on his face and, if you can get some from your vet, apply fucithalmic ointment to his eyes.

Bacterins are available to help prevent and control the disease.
Has been essentially eradicated from commercial poultry in the USA (via all in/all out).
Good management and sanitation are the best ways to avoid infectious coryza. Most outbreaks occur as a result of mixing flocks. All replacement birds on "coryza-endemic" farms should be vaccinated. The vaccine (Coryza-Vac) is administered subcutaneously (under the skin) on the back of the neck. Each chicken should be vaccinated four times, starting at 5 weeks of age with at least 4 weeks between injections. Vaccinate again at 10 months of age and twice yearly thereafter

Infectious Coryza is an acute, sometimes chronic respiratory disease. Avoid its introduction by isolating flocks and by introducing all poultry at the one time, not allowing further introductions until all those birds have left. If this is not possible, Coryza most probably will occur and should be vaccinated against.

Reference: ... hread=1217


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