Sensitivity and specificity of the fluorescent antibody technique for detection of infectious laryngotracheitis virus

The specificity of a fluorescent conjugate to infectious laryngotracheitis virus was examined using chick trachea organ culture or tissue sections infected with other avian viruses (adenovirus, infectious bronchitis, poxvirus, reovirus, Newcastle disease virus, Marek's disease virus, avian encephalomyelitis and infectious bursal agent) or Mycoplasma gallisepticum. Confirmation of virus replication in these preparations was obtained by either 1) demonstration of virus titre increase or 2) demonstration of fluorescence when using the homologous conjugate. Once either of these criteria had been satisfied, negative results with the infectious laryngotracheitis conjugate were taken to indicate that the conjugate would not present false positive results in differentiated cells infected with these heterologous viruses. The spectrum of reactivity of the infectious laryngotracheitis conjugate was then examined on organ cultures infected with several infectious laryngotracheitis isolates from across Canada. Finally, the conjugate was applied to experimental and natural cases of infectious laryngotracheitis and its efficiency was compared to routine virus isolation methods.