Infectious coryza Etiologic agent: Hemophilus paragallinarum bacteria

Test code: B0038 - Qualitative detection of Infectious coryza (Hemophilus paragallinarum bacteria) by polymerase chain reaction

B0038 is included in the poultry respiratory panel

Infectious coryza (IC) is an infectious respiratory disease found in many avian species worldwide. The causative agent of IC is Hemophilus paragallinarum. The disease can be acute to subacute at onset but typically progresses to a chronic state, with infected birds becoming carriers of the bacteria. Common names for the disease include roup, cold and coryza. In the United States, it is predominantly found in small noncommercial, menagerie, or hobby flocks. While chickens are the primary host of infectious coryza, pheasants, guinea fowl and turkeys are also susceptible.

Chronically ill or inapparent healthy carrier birds are the reservoir of infection. The source of the disease is often the addition of carrier birds to the flock. Recovered birds remain carriers and shedders for life. Transmission occurs by direct bird to bird contact, inhalation of infectious aerosols coughed into the air, or by ingestion of contaminated feed and water. The organism can be transferred on contaminated clothing, equipment and other fomites.

Coryza usually occurs in juvenile and mature birds 14 weeks of age or older. Incubation period is 1 to 3 days and the course of the acute disease stage is 4 to 12 weeks. Symptoms include nasal discharge, facial swelling, sneezing, labored breathing and fetid odor of the exudates. The infection mainly involves the upper respiratory tract--trachea, sinuses and air passages of the head.

H. paragallinarum bacteria have a polar staining and pleomorphic rod morphology. The bacterium is non-motile and gram negative. There are three antigenic types (A, B, and C) which all share certain antigens. H. paragallinarum requires both “X” and “V” factors in the media to grow.

Culture identification has traditionally been used to identify this bacterium. However, the stringent requirements for sample handling for culture for this bacterium, long incubation time and the occurrence of numerous variants of the bacteria have made culture difficult to perform and not optimally sensitive. Serological detection of H. paragallinarum is limited by availability of good monoclonal antibodies and the sensitivity of the individual assay protocol. Molecular detection by PCR has been confirmed to be the most sensitive, specific and rapid way of identifying this bacterium (Blackall, 1999).

Utilities:

• Confirm the disease causing agent
• Environmental monitoring
• Ensure that bird populations are free of H. paragallinarum
• Early prevention of spread of this bacterium among bird populations
• Minimize human exposure to this bacterium
• Safety monitoring of biological products and vaccines that derive from birds

References:
Blackall, P.J. (1999) Infectious Coryza: Overview of the Disease and New Diagnostic Options. Clin Microbiol Rev. 12: 627–632.

Specimen requirements: Throat or sinus swab, shipped overnight at room temperature.

For specimen types other than those listed here, please call to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative PCR

Normal range: Nondetected