If only 70 percent of households affected have a dog, 30 percent is still a significant number to say that it does not appear to be the family pet causing the problem. Have they considered checking how many children with hepatitis all of a sudden were vaccinated and even have the boosters? It is just a question, but something well into 90 percent range would be the more likely culprit. "Take heed that no man deceive you" (Matthew 24:4).