Bacterial Disease Infectious CoryzaPREPARED BY : MUBIN FAISAL

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Infectious Coryza

Contents1. Introduction2. Etiology 3. Species affected4. Transmission 5. Incubation Period6. Signs and Lesions7. Microscopic changes8. Differential diagnose9. Pictures of the Affected Birds10. References

IntroductionInfectious 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 asRoupContagious or infectious catarrhCold and uncomplicated Coryza

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.

EtiologyBased 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.

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.

Species affectedChickens

Pheasants

Guinea fowl

Common in game Chicken flocks .

Chickens appear to be the only natural hosts

of H. paragallinarum

TransmissionThe infection can be spread byDrinking 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.

Incubation PeriodCharacteristic 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.

Signs and Lesions

Postmortem FindingsAt 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.

Signs and LesionsSneezingInflammation 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)

In severe casesSwollen wattles (particularly in males)Difficulty in breathingBirds 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

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

A foul odour may be detected in flocks in which the disease has become chronic and complicated with other bacteria.

Signs and Lesions

Microscopic changesEssential changes in the nasal cavity, infra-orbital

sinuses, and trachea consisted ofSloughingDisintegrationHyperplasia of mucosal and glandular epitheliaThe products of mast cells, heterophils, and

macrophages may be responsible for the severe vascular changes and cell damage leading to Coryza.

Differential Diagnosis

Clinical cases of infectious Coryza can resembleSwollen head syndromeFowl pox (wet form)ChlamydiosisVitamin A deficiencyMycoplasmosis or chronic fowl cholera.

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

Typical facial edema (Note typical swelling on the face of a chicken)

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

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.

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.

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

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