Texas wiped out two strains of rabies by throwing vaccine snacks out of airplanes. By the early '90s, a dog rabies strain had jumped into coyotes in South Texas, and a separate strain was tearing through gray foxes in the west. Two people died. In 1994, Texas governor Ann Richards declared a state health emergency. In 1995, Texas started airdropping baits - small vaccine packets coated in fishmeal. Coyotes and foxes eat them and more often than not come away immune. Dog-coyote rabies cases fell from 122 in 1994 to zero by 2000. Gray fox cases fell from 244 in 1995 to zero by 2009. The gray fox strain has been declared eliminated from Texas, and the dog-coyote strain is now gone from the whole US. It's not a one-time win. Texas still flies the Mexico border every winter to keep it out, and last year expanded into far West Texas as a new fox strain moved in from New Mexico. Today, it costs Texas about $2.3 million a year. A USDA study of its first decade found every dollar saved $3 to $13, mostly in rabies shots and lab tests nobody ended up needing.