Harmful effects
Blood loss
Young animals may develop severe anemia and even die.
Flea allergy dermatitis (FAD)
Hypersensitivity to flea saliva not only causes itching and irritation after a flea bite, but is the major cause of flea allergy dermatitis (FAD). In dogs FAD typically occurs as hot spots, while in cats it takes the form of miliary dermatitis. FAD is the most common allergic skin disease of dogs and cats and is most prevalent in the summer months. The allergic reaction causes lesions, seborrhea, alopecia and pruritus leading to wounds because of constant licking and scratching.
Transmission of tapeworms
Fleas are frequently infected with the tapeworm Dipylidium caninum. When an infected flea is ingested by an animal, the infectious stages of D. caninum develop into adult tapeworms. It has to be borne in mind that young children are also exposed to the risk of acquiring a tapeworm infection due to their naturally close contact to companion animals.
Transmission of bacterial diseases
It is well known that fleas may act as vectors of various bacterial diseases. In former times plague was a real threat for mankind. Fleas can transmit various types of brucellosis in addition to typhoid fever and pasteurellosis, if they were exposed to the respective pathogens previously.