Conventional etiological, immunohistological and serological methods [18] [19] [20] were routinely used in AHV-1 identification. However, the sensitivity is usually not high enough and the methods were time-consuming since virus propagation in cell cultures is usually required and the onset of virus-induced cytopathic effect (CPE) usually requires at least 2-3 days to develop. Titration of infectious virus in cell cultures is usually achieved by the endpoint dilution method in cell monolayer. Since titration of the virus load is labor-consuming and requires about 5 days for evaluation of virus-induced CPE, distinguishing between virus-induced CPE and non-specific cell alterations may be difficult, the established real-time PCR assay will be particularly suitable in these studies. In addition, an even more important factor is that the virus from tissues of infected birds is usually not readily adapted to cell culture system during the initial several rounds of propagations [21] .