Every infection is a chain of six links, and a pathogen must complete all six to spread. That is the good news: break any single link and transmission stops. Tap each link to explore it — then cut it.
The six-link cycle
Pathogen travels clockwise · tap a link to break it
The chain of infectiontap a link to begin
Six links, one cycleAn infectious agent leaves a reservoir through a portal of exit, travels by a mode of transmission, enters a new host through a portal of entry, and finds a susceptible host — who then becomes the next reservoir. Interrupt one link and the cycle cannot continue.