Can fleas and ticks affect other pets or people?

Fleas don't discriminate. They don't mind getting on your other dog and start biting them. Or sometimes, if they're bad enough, they'll bite you. They generally don't discriminate in that sense. Ticks are kind of the same way. Once they get into the house, they don't care who they feed on, as long as they're getting a meal.

They can. If fleas or ticks are on your pet, they certainly can cause disease in humans. Fleas can easily jump from your pet, and if ticks are attached to your pet, they most likely cannot. But if they're crawling, they haven't yet taken a blood meal, and if they don't take it from your pet, they will find the next nearest warm body. If that is someone in your household, they do not distinguish. They will just try to get their next meal. Tickborne disease is a really important thing to prevent in dogs and in humans.