Geographic Range
Trichuris trichiura
is found throughout the world within temperate and tropical environments, but prefer
the moisture of the tropics.
- Biogeographic Regions
- nearctic
- palearctic
- oriental
- ethiopian
- neotropical
Habitat
Known as whipworms, this species parasitizes
humans
and monkeys. Two conditions are needed for spreading of
Trichuris trichiura
: poor sanitation, and environmental conditions that are suitable for the worm's development.
This includes a warm moist climate, low light, wet soil, and lots of rain. They are
found all over the world within temperate and tropical climates.
- Habitat Regions
- temperate
- tropical
- terrestrial
- freshwater
- Terrestrial Biomes
- desert or dune
- savanna or grassland
- chaparral
- forest
- rainforest
- scrub forest
- mountains
- Aquatic Biomes
- temporary pools
- Other Habitat Features
- urban
- suburban
- agricultural
Physical Description
Trichuris trichiura
received the common name of whipworm from their distinctive body shape. Whipworms
have an elongated anterior end that contains the mouth and esophogus that stretches
into a thread-like point. The posterior end is more blunt and contains the anus and
sex organs. Male whipworms are 30-45 mm long, females are slightly larger, measuring
35 to 50 mm. The anterior portion of the body is composed of the elongated esophagus
with unicellular glands called stichtosomes lining the wall. The posterior end contains
the organism's reproductive tract, each organism, both male and female have only a
single gonad, yet females produce a large amount of eggs per day. In males, one spicule
protrudes through a round sheath with spines for use in copulation. The anus is found
at the end of the tail but no excretory organs exist, instead the worm excretes waste
through diffusion with the environment by way of small pores in the skin.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
- sexes shaped differently
Development
The female produces about 5000 eggs per day into the lumen of the host gut. Once excreted
into the environment the embryonation period is 21 days. At this point the proper
environmental conditions are needed for development to proceed, otherwise the eggs
are durable enough to last a few months in the outside environment. If the proper
conditions are present, the eggs develop and are capable of infection if consumed.
Once consumed the eggs move down the digestive tract of humans and into the small
intestine. Here, the eggs hatch and the juveniles burrow into the epithelial lining
and mature. It takes four molts for the worm to reach maturity from the egg.
Reproduction
Whipworms are dioecious and both male and female worms have a single gonad. Males have a spiracle surrounded by a sheath with an ejaculatory duct which joins the intestine behind the terminal region of the intestine called the cloaca. The female vulva is located near the connection of the esophagus and the intestine.
Females may produce a phermomone to attract males. The male
coils around
a female with his curved area over the female genital pore. The gubernaculum, made
of cuticle tissue, guides spicules which extend through the cloaca and anus. Males
use spicules to hold the female during copulation.
Nematode
sperm are amoeboid-like and lack flagella.
- Key Reproductive Features
- sexual
- fertilization
- ovoviviparous
- Parental Investment
-
pre-fertilization
- provisioning
-
pre-hatching/birth
-
provisioning
- female
-
provisioning
Communication and Perception
Nematodes
in general have papillae,
setae and amphids
as the main sense organs. Setae detect motion (mechanoreceptors), while amphids
detect chemicals (chemoreceptors).
- Other Communication Modes
- pheromones
Food Habits
The worm enters humans as an egg, primarily from humans eating infected soil raw,
or on unwashed or uncooked vegetables. The egg makes its way to the crypts of Lieberkuhn
within the duodenum of the intestine. Here the juvenile hatches and begins to grow
and tunnel towards the surface of the lumen. Once here the worm sticks its whip like
anterior portion into the interior of the lumen while the posterior remains in the
lining of the epithelium. Once in this position it remains as an adult, laying eggs
into the gut and feeding on cellular contents and blood.
- Primary Diet
-
carnivore
- eats body fluids
- Animal Foods
- body fluids
Predation
These parasites are usually not preyed on directly, but are ingested from host to host. Larval mortality is high as most of the parasites do not reach appropriate hosts.
Ecosystem Roles
This species parasitizes humans and monkeys.
- Ecosystem Impact
- parasite
Economic Importance for Humans: Negative
One in five people, 902 million, are carriers of
Trichuris trichiura
worldwide with a one percent infection rate in the United States. The common treatment
for
Trichuris trichiura
are the drugs Albendazol and Pyrantel and both are effective and cost efficient.
Treatment can induce higher growth as well as academic achievement in children suffering
from chronic infection.
- Negative Impacts
- injures humans
Additional Links
Contributors
Renee Sherman Mulcrone (editor).
Robert Fraumann (author), University of Michigan-Ann Arbor, Solomon David (editor), University of Michigan-Ann Arbor.
- Nearctic
-
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.
- Palearctic
-
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
- oriental
-
found in the oriental region of the world. In other words, India and southeast Asia.
- Ethiopian
-
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- temperate
-
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).
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- freshwater
-
mainly lives in water that is not salty.
- desert or dunes
-
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.
- tropical savanna and grassland
-
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.
- savanna
-
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.
- temperate grassland
-
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.
- chaparral
-
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.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- rainforest
-
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 forest
-
scrub forests develop in areas that experience dry seasons.
- mountains
-
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
- marsh
-
marshes are wetland areas often dominated by grasses and reeds.
- swamp
-
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
- urban
-
living in cities and large towns, landscapes dominated by human structures and activity.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
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.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- ovoviviparous
-
reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- pheromones
-
chemicals released into air or water that are detected by and responded to by other animals of the same species
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- parasite
-
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
- causes disease in humans
-
an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).
- carnivore
-
an animal that mainly eats meat
References
Bahon, J. 1997. Colonic Obstruction and Performation Related to Heavy Trichuris trichuria infestation. Journal of Clinical Pathology , 50(7): 615-616.
Barnes, R. 1987. Invertebrate Zoology . Orlando, Florida: Dryden Press.
Bundy, D. 1998. Anthemic Treatment for Infestation with Trichurida trichiura. The Lancet , 352(9144): 1935.
Forrester, J. 1998. Randomized Trial of Albendozole and Pyrantel in Symptomless Trichuriasis in Children. The Lancet , 352(9134): 1103-1108.
Matthews, B. 1998. An Introduction to Parasitology . New York: Cambridge University Press.
Noble, E., G. Noble. 1973. Parasitology: the Biology of Animal Parasites . London: Henry Kimpton Publishers.
Roberts, L., J. Janovy. 2000. Foundations of Parasitology . New York: McGraw Hill.
Smyth, J. 1994. Intorduction to Animal Parasitology . New York: Cambridge University Press.