Easiest Way to Treat Infectious Coryza in Poultry

Cause of Infectious Coryza in Poultry

Table of Contents

The disease is caused by Avibacterium paragallinarum (previously referred to as Haemophilus paragallinarum. This causative agent belongs to the genus Avibacterium in the family Pasteurellaceae.

Some Characteristics of Avibacterium

A gram-negative, pleomorphic bacterium
Nonmotile, catalase-negative, microaerophilic
Rod shape bacterium requires nicotinamide adenine dinucleotide (V-factor) for culture.

Host range

Infectious coryza is seen primarily in pullets and laying hens and occasionally in broilers. It is most prevalent in commercial flocks and chicks having an age of less than 3 weeks.

Note: It is not a zoonotic disease.

Transmission of Infectious Coryza in Chickens

The main reservoirs of infection for A. paragallinarum are chronic or apparently healthy carrier birds. Once introduced into a flock, A. paragallinarum is spread rapidly via direct or indirect contact with infected birds, through ingestion of contaminated feed or water, and by aerosols.

Susceptible birds exposed to infected birds may show signs of the disease within 24-72 hours. Chickens who have recovered can become carriers, shedding the bacteria when stressed.

Note: Transmission does not occur via eggs.

Clinical Signs of Infectious Coryza in Poultry

Infectious coryza usually begins abruptly, with all susceptible chickens showing signs of disease within 24-72 hours after exposure to infection. The typical symptoms are

Facial swelling
Nasal discharge
Conjunctivitis
Eye discharge
Watery eyes
Sneezing
Abnormal breathing sounds
Change in voice
Coughing
Open-mouth breathing
Increased respiratory rate
Swollen wattles
Head shaking
Gurgling sounds
Depression/lethargy
Reduced appetite
Diarrhea
Weight loss
Decreased egg production
Ruffled feathers

Postmortem Findings of Infectious Coryza in Chickens

Infraorbital sinuses may be filled with a lot of profuse, greyish, semifluid exudate
Respiratory glandular and mucosal epithelia are edematous, hyperplastic, eroding, and infiltrating with heterophils, macrophages, and mast cells

How to Diagnose Infectious Coryza in Poultry Birds

A well-renowned pathologist said,

Forget the Treatment, Diagnosis is everything

Usually, in every disease, the diagnostic protocols revolve around clinical signs and symptoms and further confirmation by laboratory tests. In the same way, to diagnose infectious coryza in poultry birds, you have to check the following mentioned things:

1- A bacterial culture or PCR assay

2- A catalase-specific test

Polymerase chain reaction testing of live flocks assay has been reported to provide more accurate results as compared to bacterial culture.

Production of typical signs after inoculation with nasal exudate from infected susceptible chickens is also reliable diagnostically.

Differential Diagnosis

Infectious coryza in poultry must be differentiated from other related diseases in poultry in which birds show similar clinical signs. Some important differential diagnoses include:

Treatment of Infectious Coryza in Poultry Birds

Early treatment is crucial, hence it is advised to administer medication right away through drinking water until the medicated feed is available. Usually, erythromycin and oxytetracycline work well. Furthermore, a number of modern antimicrobials (such as fluoroquinolones and macrolides) are effective against infectious coryza. The following are the recommended treatment options for infectious coryza in poultry birds.

Name	Dosage Rate
Tylosin	Administered IM (15-30 mg/kg q6-12h) or in drinking water (250-1000 mg/L)
Sulfadimethoxine	Administered in drinking water (330-400 mg/L initially, then reduced to 200-265 mg/L x 4 days) or orally (25-55 mg/kg q24h x 3-7 days)
Norfloxacin	Administered orally (8-10 mg/kg q24h), or in drinking water (100 mg/L x 5 days)
Enrofloxacin (Baytril)	Administered in drinking water (50 mg/L) or PO, SC, IM (10-15 mg/kg)
Danofloxacin mesylate	5 mg/kg PO, IM, IV

Prevention

Vaccine: Given by intramuscular injection twice a year
Provide warm, draft-free housing in the winter
Quarantine any new birds before adding to your flock.

References

Blackall, P. J. (1999). Infectious Coryza: Overview of the Disease and New Diagnostic Options. Clinical Microbiology Reviews, 12(4), 627-632. Available here

Infectious coryza in chickens. (2022, December 2). In Wikipedia. Available here

Merck Veterinary Manual, Infectious Coryza in Chickens. Available here

The Happy Chicken Coop, All You Need to Know About Coryza in Chickens. Available here

The Poultry Site, Infectious Coryza. Available here