Fleas are parasites that feed on the blood of any warm-blooded host. The most common species is the cat flea, which often feasts on cats, dogs and humans.
Fleas transport themselves on rodents and other mammals, and usually remain on their hosts at all times. They infest both household pets and wild animals like opossums, raccoons and skunks. Fleas use their powerful legs to jump as high as 8 inches vertically and 16 inches horizontally. They can also be found on shoes, pant legs or blankets, which can transfer the fleas to new environments.
Fleas are the most common transmitter of the rare bubonic plague. They also transmit the bacterial disease murine typhus to humans through infected rats. Their saliva can cause serious flea allergy dermatitis in pets and their debris has been reported to cause similar allergic reactions in humans. Fleas can also transfer tapeworms and cause anemia in pets. Flea bites commonly cause painful, itchy red bumps.