Demonstration of infectious virus by inoculation of homogenates of clinical samples of typical APV skin lesions onto the CAM of embryonated hen's eggs is the gold standard method for diagnosis of APV, although some strains of APV do not grow readily on chicken embryos [16] . Eggs are first swabbed with 70% alcohol and a pore is made in an area over the air-cell and another one on the other side of the egg to make a false air sac and lower the CAM by negative pressure using a rubber bulb. Inoculation of infectious samples by the CAM route is performed with sterile disposable 1 mL syringe with approximately 0.1-0.2 mL of inoculum. Eggs are incubated at 37°C for 5 days with daily candling to check for embryo death. Pock lesions measuring in size 0.5-1.5 mm are observed on the membrane 3-5 days after inoculation, depending on the virulence of the virus [15, 16] . Another method of isolation of APV requires the excision and homogenization of clinical skin lesions and inoculation of a homogenate supernatant onto a permissive cell culture, such as CEF cells. This results in the formation of CPE within 4-6 days post inoculation, depending on the virus isolate and on the multiplicity of infection (MOI) [4] .