Many owners consider their household pets family members, but just like their human counterparts, these animals can spread illnesses to people.
Pet-to-human transmission is called zoonosis, and highly publicized examples include disease that's passed from nonhousehold animals to humans, such as mad cow disease and bird flu.
"Good Morning America" contributor Dr. Marty Becker gives you tips on how avoid getting sick from your pet.
Note: The animals featured on "GMA" today are available for adoption at the Humane Society of New York.
How do diseases get passed from our cats and dogs to us?
What are some of the more common diseases passed from animals to people?
The most common by far are diseases spread by parasites, such as fleas, ticks or worms. A new study from the Centers for Disease Control and Prevention found that 14 percent of the U.S. population is infected with toxocara, or internal roundworms, contracted from dogs and cats.
From roundworms, people can contract visceral larval migrans, which is a potentially serious disease that can affect the eyes or other organs. Symptoms can include fever, cough, loss of appetite, weakness and lung congestion.
Another common problem is cat scratch fever, which is just what it sounds like. It's an infection caused by a cat bite or scratch. Bacteria found on a cat's nails or claws is transmitted through the scratch and can cause high fever, loss of appetite and swollen glands.
If you're a healthy person, cat scratch fever is mild and if you wash out the scratch or bite with soap and water it can resolve itself. But it can be very dangerous for people with weakened or immature immune systems.
Contracting salmonella also is a potential problem and the most frequently reported cause of foodborne illnesses in humans. It's in the news now because of contaminated tomatoes. However, it can also be passed through animal waste, and may cause symptoms like fever, vomiting, diarrhea and exhaustion. The biggest pet culprits are reptiles, so it is important to practice excellent hygiene when caring for them.
And then there are protozoal infections. Protozoa are single-celled organisms that can be found on undercooked or raw meat, or unwashed or undercooked vegetables. Your pets have frequent contact with all those things and can pass the protozoa on to you, which can cause diarrhea that can sometimes be severe.
Who is most at risk to catch a disease from a pet?
Kids have the greatest risk of catching a disease from a pet because they not only play with their pets but often come into contact with an animal's waste, which can be hidden in the grass in the yard or in the sandbox. Inevitably, little hands that play in the grass or sand end up in little mouths.
Pregnant women, the elderly and anyone with a weakened immune system also are in danger. This includes people undergoing cancer treatment, or recent organ recipients — anyone with an autoimmune disease.