It's available on immunology we use to stick with virus antibody and antibody to stick with healthy antibody and then DAB will then go to the antibody reaction occurs, the cause of Brown, which means the virus is installed,
It uses the principles of immunology, we used antibody. To install the virus and antibody attached to the antibody and then treated DAB. Then the reaction the antibody, causing brown, which means that there is an infection.