Review on Diagnostic Methods of Infectious Coryza in Chickens

Abstract

The total poultry population in Ethiopia is estimated to be 51.35 million. The Poultry sector is a fastest growing among the animal production activities offers an opportunity to feed the fastest growing human population and provide income resources for poor farmers. There are different diseases which can affect chicken. Among the bacterial diseases, Infectious Coryza (IC) is an acute and contagious respiratory disease of chickens caused by the bacteria, Avibacterium paragallinarum. IC is distributed worldwide and typically transmitted by direct contact, airborne droplets and contamination of drinking water. But Egg transmission does not occur. The initial step in the pathogenesis of infectious coryza is adherence to and colonization of the nasal mucosa. The diagnosis can be based on a history of rapid disease spread, clinical symptoms, and pathological changes caused by IC. Diagnostic methods for IC include direct isolation, the HI test for serovar A and Polymerase Chain Reaction (PCR). Diagnosis of Avibacterium paragallinarum have been proposed as alternatives to conventional serotyping by the Page scheme. The HI test, which is one of the most widely used serological test, is often utilized to detect changes in antibody titers in cases of field infection or vaccination, and is useful for evaluating the prevalence of IC in certain areas. Rapid and accurate detection of respiratory IC has become a challenge because of the involvement of more than one agent with similar clinical signs and lesions, which complicates diagnostic decisions, as well as treatment and control strategies.