A new technology aims to stop wildlife from spreading Ebola, rabies, and other viruses. It could prevent the next pandemic by stopping pathogens from jumping from animals to people.

Imagine a cure that’s as contagious as the disease it fights—a vaccine that could replicate in a host’s body and spread to others nearby, quickly and easily protecting a whole population from microbial attacks. That’s the goal of several teams around the world who are reviving controversial research to develop self-spreading vaccines.

Their hope is to reduce infectious disease transmission among wild animals, thereby lowering the risk that harmful viruses and bacteria can jump from wildlife to humans as many experts believe happened with SARS-CoV-2, the virus that caused the COVID-19 pandemic.

The U.S. Centers for Disease Control and Prevention estimates that 60 percent of all known infectious diseases and 75 percent of new or emerging infectious diseases are zoonotic. Scientists cannot predict why, when, or how new zoonotic diseases will emerge. But when they do, these diseases are often deadly and costly to control. What’s more, many researchers predict that climate change, biodiversity loss, and population growth will accelerate their spread.