After being ingested by an herbivorous intermediate host from an aqueous environment, eggs hatch into their first larval stage, looking superficially like a mite. Many refer to these larvae as "nymphs," although they actually are a nauplius. The larvae use leg-like appendages for movement through the intermediate host. The first larval stage of (Drabick, 1987)tunnels through gut wall with a stylet, as the host elicits an immune response. The immature larvae are then encysted. Encysting can happen in a number of tissues, including the liver, lymph nodes and muscle. This stage of infection is typically asymptomatic. After a series of molts in these cysts, the third stage larvae lose the leg-like appendages and can travel in between the abdominal cavity and the abdominal wall. While the larvae are encysted, many of them die and calcify after about two years, but if the definitive, carnivorous host feeds upon the intermediate host when the larvae are in their third stage, the carnivore acquires the parasite. The larvae develop to their adult stage in the nasopharynx of the carnivorous mammals and mate.
Although sexually dimorphic, larger females attempt to find similarly sized males to mate. (Riley, 1983)females mate once over the course of their lifetime, but due to huge spermathecal storage and oocytes continuously being ejected from the ovary, females can lay thousands or millions of eggs per year.
Females can lay up to one million eggs in the definitive host per year. The eggs are about 70-90 micrometers and contain the fully-developed first stage of the larva. While many pentastomid males die directly after mating, (Hami, et al., 2009; Haugerud, 1989; Riley, 1983)males may live for a period of time after mating.
Larvae can survive for up to two years encysted before they calcify and die in the intermediate host. There was little information on the longevity of adults, but other pentastomid species can live for around ten years. (Drabick, 1987; Hami, et al., 2009)
Adult (Banaja, 1983)uses papillae on its annuli to sense its environment.
Adults ingest food in the final host's respiratory tract. Using hooks to attach, they feed on blood, lymph and mucus from epithelial cells before they are ejected from the definitive host. Larvae are primarily non-feeding, encysting in a variety of host tissues. (Drabick, 1987)
This parasite uses domesticated and wild herbivores as intermediate hosts, including sheep, goats, camels, and many other small ruminants. The definitive hosts of (Drabick, 1987; Shakerian, et al., 2008; Tavassoli, et al., 2007)include carnivores such as dogs, wolves, and coyotes. Humans can serve both roles. They are always parasitic or paratenic, causing zoonotic disease in definitive hosts or remaining asymptomatic as larvae in the paratenic host. impacts agricultural ecosystems by decreasing fitness and sometimes causing mortality in livestock. Most of this livestock is herbivorous and controlled by humans; few natural ecosystems are affected. Similarly, the chief definitive hosts of are dogs existing in urban areas, also leaving natural ecosystems relatively unaffected.
There is no known positive importance for this species.
Many human infections arise in underdeveloped areas of the world like the Middle East, India, Africa, and Southeast Asia, where eating raw glands of cattle, sheep, and other herbivorous mammals is a part of a normal diet. Infection may also be acquired through ingestion of eggs from plants or water in the environment. Infestations of the worm are frequent in humans, and deaths have even been reported due to blocked nasal passages. Because humans are often the accidental intermediate or final host of (Tavassoli, et al., 2007), the pentastomid is of medical and economic importance. Those who can afford medical help can direct their treatment either towards eliminating the nymphs in their system or relieving the symptoms of infestation through nasal sprays or antihistamines.
also frequently infects domesticated animals used for agriculture and stray animals also used for provisions. Infection in liver, mesenteric lymph nodes, and other glands may cause weakening and death of the animals, thus weakening the agricultural economy. Infection rates of small ruminants in the Middle East are significant, as up to 50% of sheep may be infected within a region.
Katie Behrmann (author), University of Michigan-Ann Arbor, Heidi Liere (editor), University of Michigan-Ann Arbor, John Marino (editor), University of Michigan-Ann Arbor, Barry OConnor (editor), University of Michigan-Ann Arbor, Renee Mulcrone (editor), Special Projects.
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.
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.
a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.
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
uses smells or other chemicals to communicate
a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
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.
fertilization takes place within the female's body
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
marshes are wetland areas often dominated by grasses and reeds.
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
having the capacity to move from one place to another.
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
an animal that mainly eats blood
reproduction that includes combining the genetic contribution of two individuals, a male and a female
mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.
living in residential areas on the outskirts of large cities or towns.
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
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.
living in cities and large towns, landscapes dominated by human structures and activity.
breeding takes place throughout the year
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