Fleas feed off the blood of a host usually a dog, cat, rat or human. They will usually live as parasites on warm-blooded vertebrates, and however, in the absence of a host, they often live in fabric with carpet being perfect for larvae to develop. In the UK fleas (although feeding on blood) are in general, not responsible for the spread of disease although in the past were thought to be responsible for the transference of the bubonic plague from rats to humans. The effects of a flea bite include an intense itching sensation and sometimes allergic reactions. Flea bites can remain itchy and inflamed for weeks causing severe discomfort. Although fleas are a common problem in UK homes were pets are present they can occur even if you do not have pets. Fleas can be carried by non-domestic animals such as rats, mice, rabbits, livestock and foxes.