FLeas are the number one cause of skin disease in pets. These blood sucking parasites inject minute amounts of saliva when they take a blood meal. This results in an irritation and causes your pet to chew and scratch. This damages the skin and allows for secondary bacterial infections to occur. Fleas will also take a meal from humans, resulting in an itchy swelling where the bite was inflicted.
Fleas are the intermediate host for tapeworms .
Tapeworm egg cases are passed with an animals feces or directly from the anus. They dry out and release tapeworm eggs into the environment. The larval stage of the flea ingests the eggs and an intermediate stage of the tapeworm develops in the growing flea. When your pet is itchy it chews at itself and ingests the flea, along with its baby tapeworm. The tapeworm then completes its lifecycle in your pet's intestine.