Immortal pathogens can have abnormal proteins attached to the surface, which confuse the immune system and protect the pathogen from an immune system attack. When immortal pathogens become intracellular, the pathogens cause normal proteins inside the cell to become abnormal. Science has identified hundreds of abnormal proteins based on shape. Abnormal proteins are a sign of chronic infection, but science has not yet correlated the abnormal protein shapes with the chronic infections generating the abnormal proteins.