Coryza Etiology Various Haemophilus paragallinarum serotypes are recognized.  Occurrence The disease is potentially encountered in any poultry-raising area but generally occurs in specific regions or countries as a chronic or seasonal problem. Coryza results in decreased egg production in commercial multi-age laying and breeder operations. Transmission Infection follows direct contact with clinically affected or asymptomatic carriers or indirect contact with contaminated equipment or personnel. The pathogen does not remain viable outside the host for periods exceeding 24 hours.  Clinical Signs Flock morbidity varies from 1 to 20%. Mortality is negligible in uncomplicated cases of coryza. Egg production in young commercial or breeder flocks is lowered following infection. Clinically affected birds show unilateral or bilateral ocular discharge progressing to facial cellulitis and chronic sinusitis. Pathology Acute cases show severe conjunctivitis and inflammation of the periorbital fascia. Chronic cases show serous to caseous sinusitis. Diagnosis Haemophilus paragallinarum can be isolated from sinus swabs in acutely affected birds. Since the organism is susceptible to desiccation it is recommended that acutely infected live birds should be submitted to a diagnostic laboratory whenever possible. Alternatively, severed heads packed on ice can be forwarded to a laboratory. Isolation involves inoculation of blood agar media streaked with Staphylococcus sp. and incubated in a candle jar. Treatment Immature birds can be treated with water-soluble sulfonamides. These drugs should not be administered to mature flocks due to contamination of eggs and the deleterious effect of sulfonamides on production and shell quality. Combinations of tetracyclines are frequently used to treat coryza and can be administered in water or injected directly by the intramuscular route. Compulsory or recommended withdrawal periods for eggs should be followed after treatment of commercial flocks. Prevention Appropriate biosecurity measures will limit the possibility of introducing infection on to breeding and commercial egg production farms. Immature flocks can be protected by administration of inactivated multivalent or homologous bacterins in aqueous suspension or oil emulsion. Two doses of inactivated vaccine should be administered by the subcutaneous or intramuscular route, as recommended by the manufacturer at four week intervals during the rearing period.   Source for this article ~ For Educational Purposes Only; Information provided in a handbook from AMERICAN SOYBEAN ASSOCIATION   Backgrounds Property of The Gander Gab/Perfect Pets ©copyright 2004   ABeeBG