Millbrook, New York, had taken their larval blood meal from (and therefore been infected by) either a white-footed mouse, a chipmunk, a short-tailed shrew, or a masked shrew. Those four hadn’t fed 90 percent of all blacklegged nymphs but, because of the differences in reservoir competence and grooming efficiency, they had fed 90 percent of those that became infected and dangerous to people.
