A hive tool touches frame after frame, hive after hive, during every inspection round. If it is never cleaned it becomes a shuttle for spores, mites and bacteria — carrying a little of whatever the last hive had straight into the next one. This model follows one hive tool down a row of hives during a routine inspection, tracking how much "spore load" it picks up and hands on depending on whether — and how — it gets sterilised in between.
Many experienced beekeepers carry two hive tools and a small propane torch or tub of washing soda solution specifically so a tool can be scorched or dunked between colonies — especially after opening a weak, dying or dead-out hive, where American foulbrood spores can otherwise remain viable in wax and wood for decades.
A single hive tool moves down a row of hives during an inspection round, and whether it gets sterilised in between decides if disease spores stay contained to one hive or spread across the whole apiary.
Every hive contact both deposits and picks up "spore load" on the tool. A flame scorch or alcohol wipe between hives strips most of that load off before it reaches the next colony; skipping it lets contamination climb hive by hive.
Choose a sterilisation method, set the row length and inspection speed, and toggle an unmanaged dead-out hive to see how a single neglected colony can seed an entire row if the tool is never cleaned.
American foulbrood spores can stay viable in old wax and hive woodware for over 40 years, which is exactly why experienced beekeepers scorch or dunk their hive tool between colonies — especially after opening a dead-out.