Every January, planes dump 1 million small plastic packets covered in fishmeal crumbles along the Texas-Mexico border. When the sharp teeth of feral dogs or coyotes pierce the plastic, a liquid rabies vaccine squirts into their mouths.
Not every animal that eats a packet becomes immune to rabies, but since the State of Texas started its oral rabies vaccination program in 1995, enough have become immune that the canine strain of rabies was eliminated from the U.S. in 2008. Continued flights keep canine rabies from re-entering the U.S. from Mexico. And though other animals, like foxes, skunks and raccoons, do still carry their own strains of the disease — and dogs and coyotes can still get these other strains from an animal bite — eliminating even one reservoir of rabies is an accomplishment.
Can this success be replicated to eliminate other zoonotic diseases — diseases that spread from animals to humans — such as plague, Lyme disease or even COVID-19? Some researchers are skeptical, like Melinda Rostal, a principal scientist in vector-borne diseases for the New York-based nonprofit EcoHealth Alliance. She says her organization prioritizes keeping people away from the animals that cause disease. The search for animal reservoirs can take decades, she says, and sometimes, when a disease is carried by mosquitoes, ticks or other vectors, it’s more effective to target these disease carriers instead.
