Fleas are a major nuisance for pets and pet owners alike. They thrive when the weather is warm and humid. Many pets reside indoors and fleas have become a year round problem with contamination of both the yard and home. Fleas are a constant source of irritation for your pet and can be the source of FAD, flea allergy dermatitis and intestinal tapeworms. They are capable of transmitting several diseases. Heavy infestations can cause iron deficiency anemia.