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Human Flea
The human flea (''Pulex irritans'') – once also called the house flea – is a cosmopolitan flea species that has, in spite of the common name, a wide host spectrum. It is one of six species in the genus '' Pulex''; the other five are all confined to the Nearctic and Neotropical realms. The species is thought to have originated in South America, where its original host may have been the guinea pig or peccary. Morphology and behavior ''Pulex irritans'' is a holometabolous insect with a four-part lifecycle consisting of eggs, larvae, pupae, and adults. Eggs are shed by the female in the environment and hatch into larvae in about 3–4 days. Larvae feed on organic debris in the environment. Larvae eventually form pupae, which are in cocoons that are often covered with debris from the environment (sand, pebbles, etc.). The larval and pupal stages are completed in about 3–4 weeks when the adults hatch from pupae, then must seek out a warm-blooded host for blood meals. The flea eg ...
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Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin; his name is rendered in Latin as and, after his 1761 ennoblement, as . Linnaeus was born in Råshult, the countryside of Småland, in southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his ' in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to co ...
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Opossum
Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 93 species in 18 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America. The Virginia opossum is the only species found in the United States and Canada. It is often simply referred to as an opossum, and in North America it is commonly referred to as a possum (; sometimes rendered as ''possum'' in written form to indicate the dropped "o"). Possums should not be confused with the Australasian arboreal marsupials of suborder Phalangeriformes that are also called possums because of their resemblance to the Didelphimorphia. The opossum is typically a nonaggressive animal. Etymology The word ''opossum'' is borrowed from the Powhatan language and was first recorded between 1607 and 1611 by John Smith (as ''opass ...
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Cosmopolitan Distribution
In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The extreme opposite of a cosmopolitan species is an endemic one, being found only in a single geographical location. Qualification The caveat “in appropriate habitat” is used to qualify the term "cosmopolitan distribution", excluding in most instances polar regions, extreme altitudes, oceans, deserts, or small, isolated islands. For example, the housefly is highly cosmopolitan, yet is neither oceanic nor polar in its distribution. Related terms and concepts The term pandemism also is in use, but not all authors are consistent in the sense in which they use the term; some speak of pandemism mainly in referring to diseases and pandemics, and some as a term intermediate between endemism and cosmopolitanism, in effect regarding pandemism as su ...
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Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago and the Russian Far East to the east. The continental landmass is bordered by the Atlantic Ocean and Africa to the west, the Pacific Ocean to the east, the Arctic Ocean to the north, and by Africa, the Mediterranean Sea, and the Indian Ocean to the south. The division between Europe and Asia as two continents is a historical social construct, as many of their borders are over land; thus, in some parts of the world, Eurasia is recognized as the largest of the six, five, or four continents on Earth. In geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on paleomagnetic data. Eurasia covers around , or around 36.2% of the Earth's total land area. It is also home to the l ...
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Yersinia Pestis
''Yersinia pestis'' (''Y. pestis''; formerly '' Pasteurella pestis'') is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both ''Yersinia pseudotuberculosis'' and ''Yersinia enterocolitica''. It is a facultative anaerobic organism that can infect humans via the Oriental rat flea (''Xenopsylla cheopis''). It causes the disease plague, which caused the first plague pandemic and the Black Death, the deadliest pandemic in recorded history. Plague takes three main forms: pneumonic, septicemic, and bubonic. ''Yersinia pestis'' is a parasite of its host, the rat flea, which is also a parasite of rats, hence ''Y. pestis'' is a hyperparasite. ''Y. pestis'' was discovered in 1894 by Alexandre Yersin, a Swiss/French physician and bacteriologist from the Pasteur Institute, during an epidemic of the plague in Hong Kong. Yersin was a member of the Pasteur school of thought. Kitasato Shibasaburō, a Japanese bacteriologist who practised Koch's me ...
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Plague (disease)
Plague is an infectious disease caused by the bacterium '' Yersinia pestis''. Symptoms include fever, weakness and headache. Usually this begins one to seven days after exposure. There are three forms of plague, each affecting a different part of the body and causing associated symptoms. Pneumonic plague infects the lungs, causing shortness of breath, coughing and chest pain; bubonic plague affects the lymph nodes, making them swell; and septicemic plague infects the blood and can cause tissues to turn black and die. The bubonic and septicemic forms are generally spread by flea bites or handling an infected animal, whereas pneumonic plague is generally spread between people through the air via infectious droplets. Diagnosis is typically by finding the bacterium in fluid from a lymph node, blood or sputum. Those at high risk may be vaccinated. Those exposed to a case of pneumonic plague may be treated with preventive medication. If infected, treatment is with antibio ...
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Dipylidium Caninum
''Dipylidium caninum,'' also called the flea tapeworm, double-pored tapeworm, or cucumber tapeworm (in reference to the shape of its cucumber-seed-like proglottids, though these also resemble grains of rice or sesame seeds), is a cyclophyllid cestode that infects organisms afflicted with fleas and canine chewing lice, including dogs, cats, and sometimes human pet-owners, especially children. Adult morphology The adult worm is about long. Gravid proglottids containing the worm's microscopic eggs are either passed in the definitive host's feces or may leave their host spontaneously and are then ingested by microscopic flea larvae (the intermediate hosts) in the surrounding environment. As in all members of family Dipylidiidae, proglottids of the adult worm have genital pores on both sides (hence the name ''double-pore tapeworm''). Each side has a set of male and female reproductive organs. The uterus is paired with 16 to 20 radial branches each. The scolex has a retractable ...
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Cestode
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish infecting parasites. All cestodes are parasitic; many have complex life histories, including a stage in a definitive (main) host in which the adults grow and reproduce, often for years, and one or two intermediate stages in which the larvae develop in other hosts. Typically the adults live in the digestive tracts of vertebrates, while the larvae often live in the bodies of other animals, either vertebrates or invertebrates. For example, '' Diphyllobothrium'' has at least two intermediate hosts, a crustacean and then one or more freshwa ...
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Free-tailed Bat
The Molossidae, or free-tailed bats, are a family of bats within the order Chiroptera. The Molossidae is the fourth-largest family of bats, containing about 110 species as of 2012. They are generally quite robust, and consist of many strong-flying forms with relatively long and narrow wings with wrinkled lips shared through their genus. Their strong flying form allows them to fly 60 miles per hour using tail winds and at altitudes over 10,000 feet. This makes them unique among bats, as they are the only bat family that withstands the elevation. They are widespread, being found on every continent except Antarctica. They are typically found in caves, abandoned mines, or tunnels. Common ancestry The family's scientific name comes from the type genus '' Molossus'', which in turn is from the Molossus breed of dogs. The family's common name is derived from a length of "free" tail, projecting beyond the end of the uropatagium—the membrane that connects the base of the tail to the hi ...
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Rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for New Zealand, Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/richochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, wh ...
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Brown Rat
The brown rat (''Rattus norvegicus''), also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat, Norwegian rat and Parisian rat, is a widespread species of common rat. One of the largest muroids, it is a brown or grey rodent with a head and body length of up to long, and a tail slightly shorter than that. It weighs between . Thought to have originated in northern China and neighbouring areas, this rodent has now spread to all continents except Antarctica, and is the dominant rat in Europe and much of North America. With rare exceptions, the brown rat lives wherever humans live, particularly in urban areas. Selective breeding of the brown rat has produced the fancy rat (rats kept as pets), as well as the laboratory rat (rats used as model organisms in biological research). Both fancy rats and laboratory rats are of the domesticated subspecies ''Rattus norvegicus domestica''. Studies of wild rats in New York City have shown that populations liv ...
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Black Rat
The black rat (''Rattus rattus''), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus ''Rattus'', in the subfamily Murinae. It likely originated in the Indian subcontinent, but is now found worldwide. The black rat is black to light brown in colour with a lighter underside. It is a generalist omnivore and a serious pest to farmers because it feeds on a wide range of agricultural crops. It is sometimes kept as a pet. In parts of India, it is considered sacred and respected in the Karni Mata Temple in Deshnoke. Taxonomy ''Mus rattus'' was the scientific name proposed by Carl Linnaeus in 1758 for the black rat. Three subspecies were once recognized, but today are considered invalid and are now known to be actually color morphs: *''Rattus rattus rattus'' – roof rat *''Rattus rattus alexandrinus'' – Alexandrine rat *''Rattus rattus frugivorus'' – fruit rat Characteristics A typical adult black rat is long, ...
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