Figure 4. Purse string–like tactic with progressive elimination (17). Numbers represent successive oral rabies vaccination (ORV) zones that attempt to roughly encircle and shrink the baited area, exclude virus incursion from outside, and lead to a maintenance zone that prevents reintroduction of the disease after the current population matures and vaccination effects are lost. Potential savings are assumed to occur within the ORV areas and for assumed distances beyond the outer zone. The rectangle bordering the rabies source (i.e., 5) highlights an area of enhanced surveillance, possible point infection control (PIC)/trap–vaccinate–release (TVR) activities, or an ORV zone intended to deter future reemergence of the virus.