dogs and cats that requires a flea intermediate host to develop. Therefore its range is dependent upon the availability of both flea and vertebrate hosts, as well as the ability to survive outside of the host until ingested by a flea. (Roberts and Janovy, 1996)is a world-wide parasite of
The first habitat for these organisms is feces of the definitive hosts, where they are still eggs. Next they live in fleas, which accquire the parasites by eating the feces. If the flea is eaten by a dog, the larval worm finds itself in the intestine where it becomes an adult and remains the rest of its life. Humans can also host the worms. We accquire them by accidentally ingesting fleas from a pet that has fleas containing juvenile worms. (Reddy, 1982)
Fleas feeding on dog feces ingest the segment. Inside the flea the egg develops into the larval form called the cysticercoid, which is not sexually mature. When it finally reaches its definitive host it can reach sexual maturity. (Roberts and Janovy, 1996)is monoecious, or hermaphroditic. Each segment of its strobilus has two sets of male and female reproductive organs (proglottids). Each proglottid will eventually contain about a dozen eggs. Segments break free from the body of the worm and exit the host via fecal excretion, where they are then available for ingestion by the intermediate host, fleas.
When (Roberts and Janovy, 1996)finally reaches its definitive host it can reach sexual maturity. Only one individual is necessary for reproduction since these worms are monecious, or hermaphroditic. Each segment of its strobilus has two sets of male and female reproductive organs (proglottids). Each proglottid will eventually contain about a dozen eggs. Segments break free from the body of the worm and exit via feces. Because of the complexity of this process it is necessary for these worms to have high reproductive potentials. In fact, tapeworms are known to produce anywhere from a few to millions of eggs in their lifetimes.
dog tapeworm, is a parasite of dogs, and sometimes cats and humans. Human infections occur most commonly in children. Its life cycle requires the use of two hosts, a flea and a vertebrate. The tapeworm eggs are ingested by flea larvae, where development reaches the larval cysticercoid stage. The vertebrate host is reached when an infected flea is ingested by the vertebrate. The worm reaches adulthood in the vertebrate and proglottids containing eggs (gravid proglottids) are excreted with feces to renew the cycle. The hexacanth larva uses its hooks to transport itself from the gut of the flea into the hemocoel. In the hemocoel, larval development continues into further juvenile stages. When detached segments are excreted from the vertebrate host, they are mobile and can easily be seen crawling around. (Chappell, et al., 1990; Roberts and Janovy, 1996), known as the
Cestodes in general have sensory organs in the scolex, which are attached to longitudinal nerves extending down the body. The nerves are attached to organs and the cestodes can detect tactile stimulation. (Brusca and Brusca, 2003)
The tapeworms are probably not intentially eaten. However, mortality is high at the egg and larval stages because the tapeworms do not reach a suitable host.
Infection with humans, though there are some reports of abdominal pain, diarrhea, irritability, and anal pruritis (Reddy, 1982). There is no discussion of pathogenicity in the dog or cat hosts, however Chappell states that infections in humans are usually limited to one worm. If the same is true for dogs and cats, then the effects of infestation should be similar. Other reports show contrary evidence, that up to 25% of infections involve multiple worms in human cases, though no difference in pathogenicity was mentioned. (Currier 1973)is often asymptomatic in
Almost all infections in humans are found in children, even infants (Reid et. al, 1992). The most likely cause of this pattern of infection is the proximity and duration of play between children and canine or feline pets. Behavior that is particulary advantageous from the tapeworm's point of view is mouth to mouth contacts between human and animal, because a recently nipped flea can still be on the mouth of the pet and then be passed into the human. A doctor from Delaware advised that "the habit of kissing canines should not be encouraged". (Reddy 1982) (Currier, et al., 1973; Reddy, 1982; Reid, et al., 1992)
Renee Sherman Mulcrone (editor).
Elizabeth Hodgson (author), University of Michigan-Ann Arbor, Eric Knapp (author), University of Michigan-Ann Arbor, Solomon David (editor), University of Michigan-Ann Arbor.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the southern part of the New World. In other words, Central and South America.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
living in landscapes dominated by human agriculture.
an animal that mainly eats meat
an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).
either directly causes, or indirectly transmits, a disease to a domestic animal
Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.
having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
having the capacity to move from one place to another.
islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.
found in the oriental region of the world. In other words, India and southeast Asia.
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
scrub forests develop in areas that experience dry seasons.
remains in the same area
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
living in cities and large towns, landscapes dominated by human structures and activity.
Brusca, R., G. Brusca. 2003. Invertebrates. Sunderland, Massachusetts: Sinauer Associates, Inc..
Chappell, C., J. Enos, H. Penn. 1990. Dipylidium caninum, an underrecognized infection in infants and children. Pediatric Infectious Disease Journal, 9(10): 745-7.
Currier, R., G. Kinzer, E. DeShields. 1973. Dipylidium caninum infection in a 14-month-old child. Southern Medical Journal, 66(9): 1060-2.
Neafie, R., A. Marty. 1993. Unusual Infections in Humans. Clinical Microbiology Reviews, 6(1): 34-56.
Ohio State University, 2001. "Dipylidium caninum (Cucumber tapeworm)" (On-line). Parasites and Parasitological Resources. Accessed October 04, 2004 at http://www.biosci.ohio-state.edu/~parasite/dipylidium.html.
Reddy, S. 1982. Infestation of a Five-Month-Old Infant with Dipylidium Caninum. Delaware Medical Journal, 54(8): 455-6.
Reid, C., F. Perry, N. Evans. 1992. Dipylidium caninum in an infant. European Journal of Pediatrics, 151(7): 502-3.
Roberts, L., J. Janovy. 1996. Foundations of Parasitology 6th edition. USA: McGraw-Hill.