Epidemiological studies on infectious coryza in chickens in northern India

Abstract

Epidemiology of infectious coryza was studied by analyzing poultry postmortem record from 1997-2001. Haemophilus puragallinarum Was isolated from 19 samples out of 65 samples taken from 35 outbreaks. These isolates were showing characteristic tiny dewdrop colonies and Gram's method of staining revealed gram-negative, pleomorphic, coccobacilli or rods. Majority of the H. paragallinarum isolates were tested catalase negative, showed oxidase activity, failed to produce indole, reduced nitrate and did not ferment galactose or trehalose. Out of 27 samples 24 were confirmed positive by polymerase chain reaction (PCR). PCR detected H. paragallinarum even from culture negative samples, which indicatedthat PCR could give significantly better results than the traditional culture. Other organisms isolated were Proteus, Staphylococcus, E. coli and Pasteurella Inultocida.