Xenopsylla Cheopisoriental Rat Flea

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Xenopsylla cheopisoriental rat flea



Geographic Range
Xenopsylla cheopis is found worldwide in association hosts, Rattus spp. (Askew, 1977; Brown, 1975; Busvine, 1966)
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with

its

primary

Other Geographic Terms cosmopolitan

Habitat
Xenopsylla cheopis usually inhabits tropical and subtropical habitats, although it has been reported in the temperate zone as well. Xenopsylla cheopis is rarely found in cold areas since it requires a tropical/subtropical climate to pupate. Fleas are prevalent in many major cities. Species of Rattus typically found in city sewer systems and other human related habitats are excellent hosts for X. cheopis. Seaports and other rat-infested areas are also common habitats for X. cheopis. Fleas are nidiculous parasites; they live in the host's nest. Clothing, beds and couches make perfect homes for many of these fleas. Fleas only attach to the host while they are sucking blood; at other times they are free-living in the host's nest. (Brown, 1975; James and Harwood, 1969)
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Habitat Regions temperate tropical terrestrial Terrestrial Biomes desert or dune savanna or grassland chaparral forest rainforest scrub forest mountains Other Habitat Features urban suburban agricultural

Physical Description
Adult Xenopsylla cheopis are about 1.5 to 4mm in length and have a laterally compressed body. Like all fleas, X. cheopis adults are wingless. Adults vary from light brown to dark brown in order to camouflage themselves in the host's fur. Adult Xenopsylla cheopis lack both genal and pronotal ctendium (combs of bristles in the front and back). Males and females are sexually dimorphic. Females have dark-colored spermatheca that resemble small sacs, a distinguishing characteristic of this species. Males have complex genitalia that are easily distinguishable from the females'. Larvae are 4.5 mm long and resemble worms; they are slender, white, eyeless, and legless. Each has fourteen bristled segments. During the last larval instar, they molt and form cocoons that are silky and covered in debris from surroundings. (Brown, 1975; James and Harwood, 1969; Rothschild, et al., 1970)
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Other Physical Features ectothermic bilateral symmetry Sexual Dimorphism sexes shaped differently

Range length 1.5 to 4 mm
0.06 to 0.16 in

Development
Fleas are holometabolous, which means they go through four life-cycle stages: egg (embryo), larva, pupa, and adult (imago). Eggs normally incubate for about two to twelve days. Xenopsylla cheopis passes through three molts during the larval stage, which usually lasts about nine to fifteen days, but can last up to 200 days in unfavorable conditions. Next, the larva spins a silk cocoon where it remains until it is finished pupating. During the pupal stage the flea's development rate is greatly affected by its surroundings. Changes in temperature and humidity outside the cocoon can inhibit emerging for up to a full year. (Askew, 1977; Brown, 1975; James and Harwood, 1969)
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Development - Life Cycle metamorphosis

Reproduction
No information is available on the mating systems of these fleas. After copulating with a male the female is ready to lay her eggs. She does this at frequent intervals while feeding. Xenopsylla cheopis prefers temperatures of 65 to 80°F with about 70% humidity for egg laying. Higher or lower temperatures inhibit females from laying their eggs. Eggs usually do not hatch on the hosts, rather on their nests since fleas are nidiculous parasites (they live on host's nests). (Askew, 1977; Brown, 1975; James and Harwood, 1969)
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Key Reproductive Features iteroparous year-round breeding

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sexual fertilization



internal

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oviparous

Breeding season These fleas breed year round, as long as the temperature and humidity favor egg-laying.
Xenopsylla cheopis is distinct from other fleas in that it has a very large egg. Studies demonstrate that eggs of X. cheopis obtain extra nutrients from their mother, hence explaining the abnormally large egg. Once eggs are laid, however, they receive no further support from their parents. (Brown, 1975; James and Harwood, 1969)
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Parental Investment pre-fertilization

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provisioning protecting female

Lifespan/Longevity
An adult X. cheopis can survive up to 100 days in temperatures of 45 to 50°F. Maximum life span for X. cheopis is 376 days. A long life span increases survival rates of Xenopsylla cheopis, thus resulting in greater a chance of transmitting pathogens. (Brown, 1975; James and Harwood, 1969)


Range lifespan Status: wild 376 (high) days

Behavior
The ideal temperature range for X. cheopis is about 65 to 80°F. Xenopsylla cheopis dislikes temperatures much higher than 80°F. Such temperatures are close to human body temperatures, therefore explaining why fleas leave the host when not feeding. Like other fleas, X. cheopis has very large legs that allow them to jump from one nest to another. An elastic protein called resilin allows fleas to store up energy and then release 97% of it in a single jump. The resilin pad becomes stretched as the flea prepares to jump and the hind femurs retract so that they are almost parallel to the rest of its body. A small catch flips and the legs then lock into place. In order to jump the flea must use its small muscles and unhook the catch, thrusting the flea into a majestic back flip. Fleas cannot control the direction of the jump; they simply land wherever the flip takes them. (Askew, 1977; Rothschild, et al., 1970)

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Key Behaviors saltatorial parasite motile

Communication and Perception
Fleas have a pygidium, a sensory organ on their dorsal side, which detects vibrations and air currents. Pupae use these signals to time their emergence from their cocoons. Not much is known about how these fleas communicate with one another. (Askew, 1977)
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Perception Channels tactile vibrations

Food Habits
Adults of both sexes of Xenopsylla cheopis feed on blood. They bite Rattus rattus (Black Rat) and other mammals, including humans. Xenopsylla cheopis obtains the host's blood through a set of external mouthparts, which consist of the following maxillary lacunae and an epipharynx. The purpose of each structure is to aid in the sucking up of blood. After biting, the fleas suck blood from a pool (telmophagy), unlike some other insects like mosquitoes that feed directly from the blood vessel (solenophagy). Piercing of the host's skin is achieved by the back and fourth action of the maxillary laciniae. After the skin is cut the epipharynx enters the wound and injects salvia. Saliva contains special chemicals, which keep the host's blood from coagulating. A canal formed by the maxillary laciniae and the epipharnyx then sucks up blood. Further down the gut a specialized organ called the proventriclus then breaks down blood cells enabling the X. cheopis to digest the blood meal. The average capacity of Xenopsylla cheopis is 0.5 cubic millimeters. The larvae of X. cheopis have mandibles, which they use to feed on detritus and the feces of the adult fleas, which are found in the nests of hosts. (Beaver, et al., 1984; James and Harwood, 1969; Rothschild, et al., 1970)
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Primary Diet carnivore

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sanguivore Animal Foods blood Other Foods detritus

Ecosystem Roles
Xenopsylla cheopis is a parasite of many mammalian species, including Rattus and humans. Because of its parasitic nature, Xenopsylla cheopis is a vector for pathogens such as plague bacilli, Yersina pestis, and murine typhus, Rickettsia typhi. Transmission of the pathogen occurs as bacteria enter the flea's gut and multiply rapidly. Soon the flea's proventriculus is

blocked by a mass of bacteria and it cannot fill its stomach, causing the flea to search for a new host. After biting the host, the blood of an uninfected host mixes with bacteria in the flea's stomach; the flea expels infected blood back into the wound consequently, infecting a new host.Xenopsylla cheopis goes from host to host infecting the uninfected. Hosts may also become infected either from consuming fecal matter or dead remnants of an infected X. cheopis. Xenopsylla cheopis carries the tapeworm of rats and mice, Hymenolepis diminut (rat tapeworm) and serves as an intermediate host for Hymenolepis nana (mouse tapeworm). (Beaty and Marquardt, 1996; Beaver, et al., 1984;Brown, 1975; James and Harwood, 1969)
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Ecosystem Impact parasite Species Used as Host


Mammalia

Economic Importance for Humans: Negative
Besides just being pesky when it bites, Xenopsylla cheopis is a vector of plague bacilli, Yersina pestis, and the agent of murine typhus, Rickettsia typhi. Both diseases are a threat to humans and other animals that encounter them. In urban foci, the reservoir hosts of plague are usually species of Rattus, most commonly Rattus rattus. (Beaty and Marquardt, 1996; Beaver, et al., 1984; Brown, 1975; James and Harwood, 1969)
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Negative Impacts injures humans



carries human disease



household pest

Conservation Status
Xenopsylla cheopis is quite common throughout the world. (James and Harwood, 1969)

Other Comments
A study done in 1997 demonstrates that X. cheopis has evolved resistance to commercial insect repellents due to its long association with humans. (Rutledge, et al., 1997)

Contributors
Allison Poor (editor), University of Michigan-Ann Arbor. Janki Trivedi (author), University of Michigan-Ann Arbor, Teresa Friedrich (editor), University of Michigan-Ann Arbor.

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