The reason why you get chickenpox is because you have a disease called chickenpox, which is an infectious disease, and the pathogen is called varicella-zoster virus, this is because this virus can cause diseases like shingles in addition to chickenpox. Therefore, the source of infection of chickenpox are people with chickenpox and people with shingles. Chickenpox is a virus that can only infect people and has only one serotype. After being infected with chickenpox, the associated virus will gradually multiply in the body, forming a viraemia, and chickenpox will appear, which is the initial infection. If you have had chickenpox once, you can gain lifelong immunity and your body’s blood circulation contains the appropriate antibodies, so you will not be infected with chickenpox again. If you have had chickenpox once, the corresponding virus will still be latent in the nerves of the body, and when the immunity is low and the virus is active again, it is still possible to get shingles again. The virus does not spread throughout the body through the bloodstream, and herpes zoster is confined to a single part of the body, not a rash all over the body, but only when the virus is first contracted.