Download H. paragallinarum

BY:asst.prof.Dr.firas AL-bawi
Infectious Coryza (IC)
INTRODUCTION
 Infectious coryza (IC) is an acute respiratory disease of chickens
caused by the bacterium known as Avibacterium paragallinarum,
once known as Haemophilus paragallinarum and Haemophilus
gallinarum.
 Av. paragallinarum and Av. gallinarum are both Gram-negative
nonmotile bacteria. In 24-hour cultures, both appear as short rods or
coccobacilli 1–3 mm in length and 0.4–0.8 mm in width, with a
tendency for filament formation.
ETIOLOGY
 Hemophilus gallinarum
 X-(hemin) and V-(nicotinamide adenine dinucleotide—NAD) factors
 Hemophilus paragallinarum V-factor
 H. gallinarum and H. paragallinarum are identical in all other growth
characteristics and disease producing potential.
Incidence and Distribution
 Infectious coryza occurs wherever chickens are raised.
 Natural and Experimental Hosts
 The chicken is the natural host for H. paragallinarum
 The following species are refractory to experimental infection:
 Turkey, pigeon, sparrow, duck, crow, rabbit, guinea pig, and mouse.
Age of Host Most Commonly Affected
 All ages are susceptible.
 Less severe in juvenile birds.
 The incubation period is shortened, and the course of the disease
tends to be longer in mature birds, especially hens with active egg
production.
Transmission, Carriers, and Vectors
 Chronic or healthy carrier birds have long been recognized as the
main reservoir of infection.
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BY:asst.prof.Dr.firas AL-bawi
 On farms where multiple-age groups are brooded and raised, spread
of the disease to successive age groups usually occurs within 1—6
weeks after such birds are moved from the brooder house to growing
cages near older groups of infected birds. Infectious coryza is not an
egg-transmitted disease.
Incubation Period
The characteristic feature is a coryza of short incubation that develops
within 24—48 hours after inoculation of chickens with either culture or
exudate. Susceptible birds exposed by contact to infected cases may show
signs of the disease within 24—72 hours. In the absence of a concurrent
infection, IC usually runs its course within 2—3 weeks.
Clinical Signs
 The most prominent features are an acute inflammation of the upper
respiratory tract including involvement of nasal passage and sinuses
with a serous to mucoid nasal discharge, facial edema, and
conjunctivitis.
 Swollen wattles may be evident, particularly in males. Rales may be
heard in birds with infection of the lower respiratory tract.
 Birds may have diarrhea, and feed and water consumption
 Usually is decreased; in growing birds, this means an increased
number of culls; and in laying flocks, this means a reduction in egg
production (10—40%). A foul odor may be detected in flocks in
which the disease has Become chronic and complicated with other
bacteria.
Gross lesion
 H. paragallinarum produces an acute catarrhal inflammation of
mucous membranes of nasal passages and sinuses.
 Frequently, a catarrhal conjunctivitis and
subcutaneous edema of face and wattles occur.
DIAGNOSIS
 Isolation and Identification of Causative Agent
 PCR
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BY:asst.prof.Dr.firas AL-bawi
Differential Diagnosis
Chronic respiratory disease, chronic fowl cholera, fowl pox, swollen head
syndrome and A-vitaminosis
INTERVENTION STRATEGIES
 Management Procedures
 Vaccination
TREATMENT
 Sulfonamides and antibiotics are useful in alleviating the severity and
course of IC .
 Erythromycin and oxytetracycline are two commonly used antibiotics.
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