Fleas are the most common.
Dr. Greg Magnusson, a veterinarian for Angie's List, says, "It takes about three months for a flea egg to develop into a flea adult so the adults that you're seeing on your pet today are laying eggs that aren't going to hatch for another three months."
Fleas can jump up to 2 feet in the air, which makes your four–legged friend, their personal breeding ground.
Indoor cat owners? You're not out of the woods. Even if your cat doesn't take a single step outside, humans can track fleas inside, also.
There's also heartworms, which are spread through mosquitoes.
Dr. Magnusson, says, "A mosquito will suck blood out of an infected dog or cat and fly over to a neighbor's house and then take a second blood meal off that dog or cat and inject the worms into that pet."
A monthly chewable can help protect your pet from heartworms, but you'll need to obtain a prescription from your vet.
Another parasite, your pet can pick up from outside, is ticks. Experts say to regularly check your pet for ticks, especially since they can transmit Lyme Disease. Angie's List says, most of the ticks we find on our dogs aren't necessarily from hiking in wooded areas, rather, from simply playing in their own backyard.
There are several effective products on the market today that protect against all three of these parasites.
To ensure your pet's protection, experts say it's critical you don't skip a dose of whatever medicine your vet recommends.