3. Contents
1. Introduction
2. Etiology
3. Species affected
4. Transmission
5. Incubation Period
6. Signs and Lesions
7. Microscopic changes
8. Differential diagnose
9. Pictures of the Affected Birds
10. References
4. Introduction
Infectious Coryza (IC) is an acute (sudden and
severe) respiratory disease of chickens caused
by Haemophilus paragallinarum (Hpg).
Also known as “fowl Coryza”.
The clinical syndrome has been described in the
early literature as
Roup
Contagious or infectious catarrh
Cold and uncomplicated Coryza
5. Cont…
The disease was named infectious Coryza
because it was infectious and affected primarily
the nasal passages (nasal discharge).
This disease is mainly observed in layers, and
cessation of egg laying occurs in affected hens.
Chickens of all ages are susceptible, but older
birds suffer more severely.
6. Etiology
Based on studies conducted during the 1930s,
the causative agent of infectious Coryza (IC)
was classified as H. gallinarum
Because of its requirement for both factor X-
(hemin) and factor V (NAD- nicotinamide
adenine dinucleotide) for growth.
H. paragallinarum is a gram-negative, non-
motile, non-spore forming, small rod shaped
capsulated bacillus bacterium.
7. Cont…
Hpg is classified into three types, A, B and C,
based on the agglutinin.
And is at least classified into 7 types from HA-1
to HA-7, based on the erythrocyte agglutinin
(HA).
A capsule may be demonstrated in virulent
strains.
8. Species affected
Chickens
Pheasants
Guinea fowl
Common in game Chicken flocks .
Chickens appear to be the only natural hosts
of H. paragallinarum
9. Transmission
The infection can be spread by
Drinking water contaminated with discharges
from the nose.
Infection can also be spread over a short
distance by the air.
Lateral spread occurs readily by direct contact.
Spread between cages with nipple drinkers
occurs more slowly.
10. Incubation Period
Characteristic feature is a Coryza of short incubation
develops within 24-48 hours after inoculation.
The latter will more consistently induce disease.
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.
IC is usually characterized by low mortality and high
morbidity.
12. Postmortem Findings
At autopsy, the mucous membranes in the
nasal cavity and infra-orbital sinus are
hypertrophied.
And pools of serous fluid and mucous are
observed inside the cavities.
When layers are infected, peritonitis, due to
deposited eggs in the peritoneal cavity, soft
shell eggs and eggs with hematomas are often
observed in the ovary.
13. Signs and Lesions
Sneezing
Inflammation of the mucous membranes of
nasal passages and the space present below
the eye (sinuses).
Mucus-like discharge from the openings of the
nose and eyes
Swelling on the face due to accumulation of
fluid under the skin is marked (subcutaneous
oedema of face).
Marked Conjunctivitis (with closed eyes)
14. In severe cases
Swollen wattles (particularly in males)
Difficulty in breathing
Birds may have diarrhea, and feed and water
consumption is usually decreased leading to
loss of weight.
Results in a drop in egg production, or an
increase in the culling (removal) of inferior,
weaker, and worthless birds.
Signs and Lesions
15. Upper trachea may be involved but the lungs
and air-sacs are affected only in chronic,
complicated cases.
Chronic cases show serous to caseous sinusitis.
Typically, pneumonia and air-sacculitis are
rarely present
Rales may be heard in birds with infection of
the lower respiratory tract.
Signs and Lesions
16. A foul odour may be detected in flocks in
which the disease has become chronic and
complicated with other bacteria.
Signs and Lesions
17. Microscopic changes
Essential changes in the nasal cavity, infra-
orbital sinuses, and trachea consisted of
Sloughing
Disintegration
Hyperplasia of mucosal and glandular
epithelia
The products of mast cells, heterophils, and
macrophages may be responsible for the
severe vascular changes and cell damage
leading to Coryza.
18. Differential Diagnosis
Clinical cases of infectious Coryza can resemble
Swollen head syndrome
Fowl pox (wet form)
Chlamydiosis
Vitamin A deficiency
Mycoplasmosis or chronic fowl cholera.
19. Some of the following pictures given below show the
symptoms signs and lesions of the Infectious Coryza (IC)
Eyelids stick together by Watery swollen eyes and face,
mucous and exudates purulent nasal exudates
21. Ocular discharge and swelling of the nasal sinus associated with Coryza.
Differential diagnosis includes Mycoplasmosis or Laryngotracheitis.
Accumulation of purulent material in the
infra-orbital sinus is characteristic of Coryza
22. Section of maxilla cut between a nostril and the eyes. In the affected bird,
mucous membrane in the nasal cavity and infra-orbital sinus are
hypertrophied, and a pool of mucous fills inside the cavities.
Right: A healthy chicken as a control.
23. Treatment
Immature birds can be treated with water-soluble
sulfonamides.
These drugs should not be administered to
mature flocks due to residues in eggs and the
deleterious effect of sulfonamides on production
and shell quality.
Combinations of tetracyclines are frequently
used to treat Coryza by administration in water or
injected directly by the intramuscular route.
24. References: -
1. Common Poultry Diseases (G.D. Butcher, J.P. Jacob, And F.B. Mather)
2. Handbook Of Poultry Diseases Important In Africa (A Project Of The
Global Livestock CRSP)
3. Diseases of Poultry / Edited By Y. M. Saif. (11th Edition)
4. Poultry Diseases
Simon M. Shane, FRCVS, PhD, MBL, ACPV- Adjunct Professor
North Carolina State University
Professor Emeritus, School of Veterinary Medicine
Louisiana State University USA
5. Important Poultry Diseases (Manual)
6. Colour Manual Diseases of Birds (Edited By: Japanese Society On
Poultry Diseases)
7. A Colour Atlas Of Poultry Diseases (By: J.L. Vegad)
8. Picture Book of Infectious Poultry Diseases. (The ECTAD Southern
Africa Team)
9. http://www.thepoultrysite.com/diseaseinfo/82/infectious-coryza
