Infectious Coryza

Infectious Coryza

A highly contagious upper respiratory disease of chickens.

Alternative names of Infectious Coryza

Roup, Catarrh, Cold, Hemophilus Infection, and Infectious Catarrh.

Etiologic agent of Infectious Coryza

Avibacterium paragallinarum.

Former name of Avibacterium paragallinarum

Haemophilus paragallinarum.

Gram reaction of Avibacterium paragallinarum

Gram-negative.

Cell morphology of Avibacterium paragallinarum

Pleomorphic rod.

Motility of Avibacterium paragallinarum

Nonmotile.

Catalase reaction of Avibacterium paragallinarum

Catalase-negative.

Oxygen requirement of Avibacterium paragallinarum

Microaerophilic.

Growth factor required for culture

Nicotinamide adenine dinucleotide (V factor).

Characteristic colony appearance

Satellite colonies with dewdrop-shaped appearance.

Primary host of Infectious Coryza

Chickens.

Mode of transmission

Direct contact with infected birds or asymptomatic carriers.

Indirect transmission of Infectious Coryza

Contaminated equipment and personnel.

Egg transmission of Infectious Coryza

Does not occur.

Main source of infection

Clinically affected birds and carrier birds.

Mild clinical sign of Infectious Coryza

Listlessness.

Characteristic nasal discharge

Serous nasal discharge.

Characteristic facial lesion

Slight facial swelling.

Severe ocular lesion

Conjunctivitis.

Periorbital lesion

Inflammation of the periorbital fascia.

Most commonly affected facial structure

Infraorbital sinuses.

Characteristic respiratory signs

Facial swelling, nasal discharge, and conjunctivitis.

Diagnosis of Infectious Coryza

History, clinical signs, bacterial isolation, and laboratory confirmation.

Characteristic laboratory finding

Dewdrop-shaped satellite colonies.

Treatment of choice

Erythromycin.

Alternative treatment

Oxytetracycline.

Purpose of antibiotic treatment

Reduce clinical signs and control infection.

Best preventive measure

Good biosecurity and preventing introduction of carrier birds.

Carrier birds

Birds that appear healthy but continue to spread the organism.

Disease classification

Bacterial upper respiratory disease.

Characteristic culture requirement

V factor (NAD).

Key differentiating feature from Mycoplasmosis

Not transmitted through eggs.

Most important transmission route

Direct contact with infected or carrier birds.