I think it's not really possible. Last year I was also concerned about the problem of lice in my dog. I tried to protect my Mr. Stuffy from fleas as much as possible. I washed him with special flea shampoos and tried to protect him from communicating with other dogs. One day I bought my Stuffy a
Cricket Ball Toy and didn't keep track of how he started playing with his ball with the neighbor's dog. The neighbor then apologized and reported that his dog had fleas. But nothing was transmitted through the toy. Since then, I'm not so afraid that my dog will get infected with fleas, it's still easy to get them out nowadays.