Fleas are common external parasites that feed on animal blood, producing itching, skin irritation, and perhaps allergic reactions. They can also spread illnesses.
Ticks cling to animals in order to feed on their blood. They can spread infections like Lyme disease, ehrlichiosis, and anaplasmosis.
Mosquitoes can transmit diseases like heartworm to dogs and cats. Heartworm disease can cause major health problems, such as heart failure.
Lice are microscopic, wingless insects that live in pet fur. They can be a nuisance even if they are species-specific, causing irritation and itching.
Ear mites and sarcoptic mange mites, among others, can cause itching, hair loss, and skin irritation in pets. Ear mites are parasites that live in the ears and can cause infections.
Certain fleas, such as the brown dog tick, are capable of transmitting diseases such as Rocky Mountain spotted fever and canine babesiosis.
Cheyletiella mites, commonly known as walking dandruff, can infest your pet's skin and fur, producing itching and flaky skin.
Stinging insects can be dangerous to pets if they get stung. Allergic reactions to stings can be minor to severe, and numerous stings can be fatal.
The human flea can cause itching, redness, and pain in pets. While it prefers human hosts, it can bite and annoy animals.