when is chickenpox contagious
Chickenpox incubation period. Chickenpox (varicella) is a common, highly contagious, viral infectious disease of childhood. Usually mild, itâs characterised by a very itchy rash that can spread over the whole body. In the UK, it is common and most cases occur during winter and spring.he incubation period is seven to 21 (usually 10 to 21) days after exposure to the herpes varicella-zoster virus to the development of the symptoms. The disease is most contagious a day or two before the rash appears and until the rash is completely dry and scabbed over, about five to six days after onset of the rash.