Editing Flea (section)

=== Direct effects of bites ===
{{Main|Pulicosis}}
[[File:Jigger infested foot (2).jpg|thumb|Human foot infested with jigger fleas, ''[[Tunga penetrans]]'']]

In many species, fleas are principally a nuisance to their hosts, causing an [[itch]]ing sensation which in turn causes the host to try to remove the pest by biting, pecking or scratching. Fleas are not simply a source of annoyance, however. Flea bites cause a slightly raised, swollen, irritating nodule to form on the epidermis at the site of each bite, with a single puncture point at the centre, like a [[mosquito]] bite.<ref name="Mullen">{{cite book |title=Medical and Veterinary Entomology |last=Mullen |first=Gary R. |author2=Mullen, Gary|author3=Durden, Lance |year=2009 |publisher=Academic Press |isbn=978-0-12-372500-4 |page=637 |url=https://books.google.com/books?id=6R1v9o-uaI4C }}</ref>{{rp|126}} This can lead to an [[eczema]]tous itchy skin disease called [[flea allergy dermatitis]], which is common in many host species, including dogs and cats.<ref name=Krasnov72>{{cite book|author=Krasnov, Boris R. |title=Functional and Evolutionary Ecology of Fleas: A Model for Ecological Parasitology |url=https://books.google.com/books?id=tkvr8h8zxFwC&pg=PA72 |year=2008 |publisher=Cambridge University Press |isbn=978-1-139-47266-1 |pages=72–74}}</ref> The bites often appear in clusters or lines of two bites, and can remain itchy and inflamed for up to several weeks afterwards. Fleas can lead to secondary hair loss as a result of frequent scratching and biting by the animal. They can also cause [[anemia]] in extreme cases.<ref name="Mullen"/>{{rp|126}}