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− | {{otheruses}}
| + | <noinclude><translate><!--T:1--> |
− | {{Taxobox
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− | | name = Flea
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− | | image = Scanning_Electron_Micrograph_of_a_Flea.jpg
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− | | image_width = 200px
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− | | image_caption = [[Scanning electron microscope]] (SEM) depiction of a flea
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− | | domain = [[Eukaryote|Eukaryota]]
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− | | regnum = [[Animal]]ia
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− | | phylum = [[Arthropod]]a
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− | | classis = [[Insect]]a
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− | | subclassis = [[Pterygota]]
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− | | infraclassis = [[Neoptera]]
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− | | superordo = [[Endopterygota]]
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− | | ordo = '''Siphonaptera'''
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− | | ordo_authority = [[Pierre André Latreille|Latreille]], [[1825]]
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− | | subdivision_ranks = [[Infraorder]]s
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− | | subdivision =
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− | [[Ceratophyllomorpha]]<br />
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− | [[Hystrichopsyllomorpha]]<br />
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− | [[Pulicomorpha]]<br />
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− | [[Pygiopsyllomorpha]]<br />
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− | | synonyms =
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− | Aphaniptera
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− | }}
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− | '''Flea''' is the [[common name]] for any of the small wingless [[insect]]s of the [[order (biology)|order]] '''Siphonaptera''' (some authorities use the name '''Aphaniptera''' because it is older, but [[circumscriptional name|names above family rank]] need not follow the [[ICZN]] rules of priority, so most taxonomists use the more familiar name). Fleas are external [[parasite]]s, living by [[hematophagy]] off the [[blood]] of [[mammal]]s and [[bird]]s. Genetic and morphological evidence indicates that they are descendants of the [[Scorpionfly]] family [[Boreidae]], which are also flightless; accordingly it is possible that they will eventually be reclassified as a suborder within the [[Mecoptera]]. In the past, however, it was most commonly supposed that fleas had evolved from the [[fly|flies]] ([[Diptera]]), based on similarities of the larvae. In any case, all these groups seem to represent a [[clade]] of closely related insect lineages, for which the names [[Mecopteroidea]] and [[Antliophora]] have been proposed.
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| + | {{ |
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− | Some well known flea species include:
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− | * [[Cat flea]] (''Ctenocephalides felis''),
| + | Species id |
− | * [[Dog flea]] (''Ctenocephalides canis''),
| + | | common_name = Flea |
− | * [[Human flea]] (''Pulex irritans''),
| + | | image = Scanning_Electron_Micrograph_of_a_Flea.jpg |
− | * [[Northern rat flea]] (''Nosopsyllus fasciatus''),
| + | | latin_name = Siphonaptera |
− | * [[Rat flea|Oriental rat flea]] (''Xenopsylla cheopis'').
| + | | order = '''Siphonaptera''' |
| + | | description = |
| + | Fleas are external parasites, living off the blood of mammals and birds. |
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− | ==Morphology and behavior==
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− | [[Image:Scheme_flea_anatomy-en.svg|thumb|Diagram of a Flea|350px|left]]
| + | Fleas are small (1/16 to 1/8-inch (1.5 to 3.3 mm) long), agile, usually dark colored (for example, the reddish-brown of the cat flea), wingless insects with tube-like mouthparts adapted to feeding on the blood of their hosts. Their bodies are flattened side to side, permitting easy movement through the hairs or feathers on the host's body. Their legs are long, the hind pair well adapted for jumping (vertically up to seven inches (18 cm); horizontally thirteen inches (33 cm) - around 200 times their own body length, making the flea the best jumper out of all animals (in comparison to body size). The flea body is hard, polished, and covered with many hairs and short spines directed backward, allowing the flea a smooth passage through the hairs of its host. |
− | Fleas are small (1/16 to 1/8-[[inch]] (1.5 to 3.3 mm) long), agile, usually dark coloured (for example, the reddish-brown of the cat flea), wingless insects with tube-like mouthparts adapted to feeding on the blood of their hosts. Their bodies are laterally compressed (that is, flattened side to side), permitting easy movement through the hairs or feathers on the host's body. Their legs are long, the hind pair well adapted for jumping (vertically up to seven inches (18 cm); horizontally thirteen inches (33 cm)<ref name=Ohio> [http://ohioline.osu.edu/hyg-fact/2000/2081.html Fleas, HYG-2081-97] William F. Lyon, [[Ohio State University]] entomology page. Accessed 28 December 2006</ref>) - around 200 times their own body length, making the flea the best jumper out of all animals (in comparison to body size). The flea body is hard, polished, and covered with many hairs and short spines directed backward<ref name=Florida>[http://edis.ifas.ufl.edu/IG087 Fleas] - P.G. Koehler and F. M. Oi. Printed July 1993, revised February 2003. Provided by the [[University of Florida]]</ref>, allowing the flea a smooth passage through the hairs of its host. Its tough body is able to withstand great pressure, likely an adaptation to survive scratching etc. Even hard squeezing between the fingers is normally insufficient to kill the flea; it may be necessary to crush them between the fingernails or roll them between the fingers or put them in fire safe area and burn them with match or lighter. | |
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− | [[Image:HookeFlea01.jpg|thumb|right|[[Robert Hooke|Hooke's]] drawing of a flea in ''[[Micrographia]]'']]
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− | Fleas lay tiny white oval shaped eggs. Their larvae are small and pale with bristles covering their worm-like body. They are without eyes, and have mouthparts adapted to chewing. While the adult flea's diet consists solely of blood, their larvae feed on various organic matter including the feces of mature fleas.<ref name=BugGuide>[http://bugguide.net/node/view/7040 Order Siphonaptera - Fleas - BugGuide.Net] Accessed 28 December 2006</ref> In the pupae phase the larvae are enclosed in a silken, debris covered cocoon. | + | Fleas attack a wide variety of warm-blooded vertebrates including dogs, cats, humans, chickens, rabbits, squirrels, rats and mice. Fleas are a nuisance to their hosts, causing an itching sensation which in turn may result in the host attempting to remove the pest by biting, pecking, scratching etc the vicinity of the parasite. Fleas are not simply a source of annoyance, however. Some people and animals suffer allergic reactions to flea saliva resulting in rashes. Flea bites generally result in the formation of a slightly-raised swollen itching spot with a single puncture point at the center. The bites often appear in clusters or lines, and can remain itchy and inflamed for up to several weeks afterwards. Fleas can also lead to hair loss as a result of frequent scratching and biting by the animal, and can cause anemia in extreme cases. |
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− | ==Life cycle and habitat==
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− | Fleas are [[holometabolism|holometabolous]] insects, going through the four [[Biological life cycle|life cycle]] stages of [[embryo]], [[larva]], [[pupa]] and [[imago]] (adult). The flea life cycle begins when the female lays after feeding. Adult fleas must feed on blood before they can become capable of reproduction.<ref name="Florida" /> Eggs are laid in batches of up to 20 or so, usually on the host itself, which easily roll onto the ground. As such, areas where the host rests and sleeps become one of the primary [[habitat]]s of eggs and developing fleas. The eggs take around two days to two weeks to hatch<ref name="Ohio" />.
| + | Besides the problems posed by the creature itself, fleas can also act as a vector for disease. For example, fleas transmitted the bubonic plague between rodents and humans by carrying ''Yersinia pestis'' bacteria. |
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− | [[Image:Flea Larva.jpg|right|thumb|[[Micrograph]] of a flea larva.]]
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− | Flea larvae emerge from the eggs to feed on any available organic material such as dead insects, feces and vegetable matter. They are blind and avoid sunlight, keeping to dark places like sand, cracks and crevices, and bedding. Given an adequate supply of food, larvae should pupate within 1-2 weeks. After going through three larval stages they spin a [[silk]]en cocoon. After another week or two the adult flea is fully developed and ready to emerge from the cocoon. They may however remain resting during this period until they receive a signal that a host is near - vibrations (including sound), heat and [[carbon dioxide]] are all stimuli indicating the probable presence of a host.<ref name="Ohio" /> Fleas are known to [[overwinter]] in the larval or pupal stages.
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− | | + | <noinclude></translate></noinclude> |
− | Once the flea reaches adulthood its primary goal is to find blood - adult fleas must feed on blood in order to reproduce[http://edis.ifas.ufl.edu/IG087]. Adult fleas only have around a week to find food once they emerge, though they can survive two months to a year between meals. A flea population is unevenly distributed, with 50 percent eggs, 35 percent larvae, 10 percent pupae and 5 percent adults.<ref name="Ohio" /> Their total life cycle can take as little as two weeks, but may be lengthened to many months if conditions are favourable. Female fleas can lay 500 or more eggs over their life, allowing for phenomenal growth rates.
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− | ==Evolution and classification==
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− | Fleas are apparently related to [[scorpionfly|scorpionflies]]<ref name=Grimaldi>[[David Grimaldi|Grimaldi, D.]] and [[Michael S. Engel|Engel, M.S.]] ([[2005]]). ''Evolution of the Insects''. [[Cambridge University Press]]. ISBN 0-521-82149-5.</ref>, winged insects with good eyesight. The flightless [[Boreidae|snow flea]] with its [[vestigial structure|rudimentary]] wings seems to be close to the common ancestor of the 2000 or so currently known varieties of flea, which split off in many directions around 160 million years ago.<ref name="Grimaldi" /> Their evolution continued to produce adaptations for their specialized parasitic niche, such that they now have no wings and their eyes are covered over. The large number of flea species may be attributed to the wide variety of host species they feed on, which provides so many specific [[ecological niche]]s to adapt to.
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− | Flea [[systematics]] is not entirely fixed. While compared to many other insect groups fleas have been studied and classified fairly thoroughly, details still remain to be learned about the [[evolution]]ary relationships among the different flea lineages.
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− | [[Infraorder]] [[Pulicomorpha]]
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− | * [[Superfamily]] [[Pulicoidea]]
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− | ** [[Family]] [[Hectopsyllidae]] – sticktight and [[chigoe flea]]s ("chiggers" of [[Latin America]])
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− | ** Family [[Pulicidae]] – common fleas
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− | * Superfamily [[Malacopsylloidea]]
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− | ** Family [[Malacopsyllidae]]
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− | ** Family [[Rhopalopsyllidae]] – hosts: marsupials
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− | * Superfamily [[Vermipsylloidea]]
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− | ** Family [[Vermipsyllidae]] – hosts: carnivores
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− | * Superfamily [[Coptopsylloidea]]
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− | ** Family [[Coptopsyllidae]]
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− | * Superfamily [[Ancistropsylloidea]]
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− | ** Family [[Ancistropsyllidae]]
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− | Infraorder [[Pygiopsyllomorpha]]
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− | * Superfamily [[Pygiopsylloidea]]
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− | ** Family [[Lycopsyllidae]]
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− | ** Family [[Pygiopsyllidae]]
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− | ** Family [[Stivaliidae]]
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− | Infraorder [[Hystrichopsyllomorpha]]
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− | * Superfamily [[Hystrichopsylloidea]]
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− | ** Family [[Hystrichopsyllidae]] – hosts: rats and mice. Includes Ctenopsyllidae, Amphipsyllidae
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− | ** Family [[Chimaeropsyllidae]]
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− | * Superfamily [[Macropsylloidea]]
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− | ** Family [[Macropsyllidae]]
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− | * Superfamily Stephanocircidoidea
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− | ** Family [[Stephanocircidae]] - hosts: rodents
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− | Infraorder [[Ceratophyllomorpha]]
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− | * Superfamily [[Ceratophylloidea]]
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− | ** Family [[Ceratophyllidae]] - hosts: rodents and birds. Includes Dolichopsyllidae
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− | ** Family [[Leptopsyllidae]] – hosts: mice and rats
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− | ** Family [[Ischnopsyllidae]] – hosts: bats
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− | ** Family [[Xiphiopsyllidae]]
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− | <!-- Hypsophthalmidae is almost certainly a synonym, but of what? -->
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− | ==Relationship with host==
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− | [[Image:Fleabite.JPG|thumb|left|Flea bites on the back of a human]]
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− | [[Image:Fleabite-closeup.jpg|thumb|right|Flea bite on the waist of a human with no reaction]]
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− | Fleas attack a wide variety of [[warm-blooded]] [[vertebrate]]s including dogs, cats, humans, chickens, rabbits, squirrels, rats and mice. Fleas are a nuisance to their hosts, causing an [[itch]]ing sensation which in turn may result in the host attempting to remove the pest by biting, pecking, scratching etc the vicinity of the parasite. Fleas are not simply a source of annoyance, however. Some people and animals suffer [[allergic reaction]]s to flea [[saliva]] resulting in [[rash]]es. Flea bites generally result in the formation of a slightly-raised swollen itching spot with a single puncture point at the center. The bites often appear in clusters or lines, and can remain itchy and inflamed for up to several weeks afterwards. Fleas can also lead to hair loss as a result of frequent scratching and biting by the animal, and can cause [[anemia]] in extreme cases.
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− | Besides the problems posed by the creature itself, fleas can also act as a [[vector (biology)|vector]] for [[disease]]. For example, fleas transmitted the [[bubonic plague]] between rodents and humans by carrying ''[[Yersinia pestis]]'' bacteria. Murine typhus (endemic typhus) fever, and in some cases ''[[Hymenolepiasis]]'' ([[tapeworm]]) can also be transmitted by fleas.
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− | == Flea treatments ==
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− | ===For humans===
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− | [[Image:Fleadirt.jpg|thumb|right|Flea "dirt" in the fur of a cat is actually excess blood (from host) consumed by the adult flea, passed as feces.]]
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− | The itching associated with flea [[bite]]s can be treated with [[antipruritic|anti-itch creams]], usually [[antihistaminic]]s or [[hydrocortisone]]. [[Calamine lotion]] has been shown to be ineffective for itching.
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− | ===For pets===
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− | {{Unrefsec|date=February 2008}}
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− | The fleas, their larvae, or their eggs can be controlled with [[insecticide]]s. [[Lufenuron]] is a veterinary preparation (Program) that attacks the larval flea's ability to produce [[chitin]] but does not kill fleas. Flea medicines need to be used with care as many, especially the [[acetylcholinesterase inhibitor]]s, also affect mammals. Popular brands of topicals that do not contain cholinesterase inhibitors include Advantage, Advantix, and Frontline and Frontline PLUS.
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− | Even though organophosphate-based insecticides are still sold as flea collars, flea powders and flea shampoos, those are not recommended. Many strains of insects have become resistant against that class of compounds, and they display an unacceptably high level of toxicity against mammals.
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− | ===For the home===
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− | Combating a flea infestation in the home takes patience as for every flea found on an animal there are many more developing in the home. A spot-on insecticide, such as Advantage, Frontline or Revolution will kill the fleas on the pet and in turn the pet itself will be a roving flea trap and mop up newly hatched fleas. The environment ought to be treated with a fogger or spray insecticide containing an [[juvenile hormone|insect growth regulator]], such as [[pyriproxyfen]] or [[methoprene]] to kill eggs and pupae, which are quite resistant against insecticides. Frequent vacuuming is also helpful, but you must immediately dispose of the vacuum bag afterwards. Recent studies have shown that vacuuming may kill fleas almost as effectively as insecticides.
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− | [[Diatomaceous earth]] can also be used as an effective home flea treatment in lieu of [[acetylcholinesterase]] inhibitory treatments or insecticides which carry with them a risk of poisoning for both humans and animals. Diatomaceous earth absorbs lipids from the cuticle, the waxy outer layer of insects' exoskeletons, causing them to dehydrate and can be purchased at most gardening suppliers or online. It can then be evenly distributed around the house (especially in corners and near furniture) with any type of shaker (salt shaker, spice shaker, etc.) and then vacuumed away after about 7 days. Diatomaceous earth also has the added benefit of killing many other types of insects that might be residing in your house.
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− | Dried [[pennyroyal]] has also been recommended as a natural flea control.<ref>[http://www.motherearthnews.com/Livestock-and-Farming/1987-07-01/Natural-Flea-Control.aspx Natural Flea Control], 1987, [http://www.motherearthnews.com Mother Earth News], Retrieved 2007-12-18</ref>
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− | ==Other==
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− | [[Image:Flealarcomuseum.jpg|thumb|right|175px|Moche Flea. 200 A.D. [[Larco Museum|Larco Museum Collection]] Lima, Peru.]]
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− | The [[Moche]] people of ancient [[Peru]] worshipped nature.<ref> Benson, Elizabeth, The Mochica: A Culture of Peru. New York, NY: Praeger Press. 1972</ref> They placed emphasis on animals and even depicted fleas in their art. <ref>Berrin, Katherine & Larco Museum. ''The Spirit of Ancient Peru:Treasures from the [[Larco Museum|Museo Arqueológico Rafael Larco Herrera]].'' New York: [[Thames and Hudson]], 1997.</ref>
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− | == See also ==
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− | * [[Anti-itch drug]]
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− | * [[Bubonic Plague]]
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− | == References ==
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− | <references/> | |
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− | == External links ==
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− | {{commonscat|Siphonaptera}}
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− | * {{dmoz|Science/Biology/Flora_and_Fauna/Animalia/Arthropoda/Insecta/Fleas/}}
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− | * [http://npic.orst.edu/pest2.htm#fleas Flea Pest Control Information - National Pesticide Information Center]
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− | * [http://parents.berkeley.edu/advice/health/fleas.html Advice about fleas] from the Berkeley Parents Network
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− | * [http://www.lib.uiowa.edu/hardin/md/fleabites.html Links to flea bite pictures (Hardin MD/Univ of Iowa)]
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− | * [http://www.primalnature.org/wildlife.html Good Neighbors] An essay on the natural history of the flea
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− | *[http://eastvillagepodcasts.com/2006/06/13/my-foot-and-sand-flea-bites/ Sand Flea Bite Picture]
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− | *[http://www.wood.army.mil/chmdsd/Army_Chemical_Review/pdfs/Jul-Dec%202005/Kirby.pdf Flea As Weapon]
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− | [[Category:Pest insects]]
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− | [[Category:Fleas| ]]
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− | [[Category:Insects]]
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− | [[Category:Dog health]]
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− | [[Category:Cat health]]
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− | [[Category:Veterinary entomology]]
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