A design pattern for conditions such as post-herpetic neuralgia or postinfectious encephalitis, where the disease is secondary to the initial infection.
TODO: write better guidelines on what constitutes a secondary disease vs primary. * We do not use this pattern for AIDS-HIV for example, instead representing this is using SubClassOf. * We draw a distinction between infectious and postinfectious encepahlitis. * we do not use this pattern for chickenpox, but we do for shingles