Echinostoma revolutum

Ge­o­graphic Range

Echi­nos­toma rev­o­lu­tum can be found in the snail Lym­naea elodes in North Amer­ica (Serensen et al., 1997) and in other lym­naeid species across Eura­sia. It has been re­ported from Ger­many, Aus­tria, Poland, Bul­garia, Eng­land, Rus­sia, Malaysia, Thai­land, India, and Viet­nam (Kanev, 1994). (Kanev, 1994; Sorensen, et al., 1997)

Habi­tat

Eggs of Echi­nos­toma rev­o­lu­tum are found in fresh water habi­tats (Kanev, 1994) where wa­ter­fowl occur. The sub­se­quent life stages are all found in in­ter­me­di­ate or de­fin­i­tive hosts, all of which are found in the same still or slow-mov­ing fresh­wa­ter habi­tats. As a miracid­ium, E. rev­o­lu­tum can be found in the ovotestis or di­ges­tive gland of the in­ter­me­di­ate host (Kanev, 1994). Stud­ies have shown that Lym­naea stag­nalis is a wide­spread spread and com­mon in­ter­me­di­ate host for E. rev­o­lu­tum (Kanev, 1994). (Kanev, et al., 1995; Kanev, 1994)

  • Aquatic Biomes
  • lakes and ponds
  • temporary pools

Phys­i­cal De­scrip­tion

E. rev­o­lu­tum is the nom­i­nal mem­ber of the 37-col­lar-spined E. rev­o­lu­tum group (Kanev, 1994; Kanev et al., 1995). The group con­sists of the closely re­lated species: E. rev­o­lu­tum (Froelich, 1802), E. echi­na­tum (Zeder, 1803), E. triv­o­lvis (Cort, 1914), E. ju­rini (Skvort­zov, 1924), E. caproni (Richard, 1964), and E. paraen­sei (Lie and Basch, 1967). All miracidia in this group have eigh­teen epi­der­mal plates, show­ing a com­mon pat­tern of 6:6:4:2 (an­te­rior to pos­te­rior), six body papil­lae, two eye­spots, and two ex­cre­tory pores (Dim­itrov et al., 1999).

At time of ini­tial in­fec­tion, metac­er­cariae av­er­age 240 mi­crom­e­ters long and 0.02 square mm in body area. By day 14 post in­fec­tion, worms reach an av­er­age of 3.5 mm in length and 2.0 square mm in body area (Humphries et al., 1997). (Dim­itrov, et al., 1999; Humphries, et al., 1997)

De­vel­op­ment

Adult E. rev­o­lu­tum use avian species, pri­mar­ily wa­ter­fowl as their de­fin­i­tive hosts. Adults are her­maph­ro­dites and live four to eight weeks, oc­cu­py­ing the di­ges­tive tract of in­fected birds (Sorensen and Minchella, 1998). Adults begin to pro­duce and re­lease many self-fer­til­ized eggs ten days after in­fect­ing the de­fin­i­tive host (Kanev, 1994).

Eggs: The eggs hatch in fresh water in nine to twelve days. Ex­po­sure to light stim­u­lates hatch­ing. Eggs hatch into miracidia (Kanev, 1994).

Miracid­ium: The swim­ming lar­val stage can sur­vive six to eight hours be­fore it finds a pri­mary in­ter­me­di­ate host, which must be a snail in the fam­ily Lym­naei­dae (Kanev, 1994). Once a miracid­ium suc­cess­fully in­fects the ovotestis/di­ges­tive gland area of the host, it asex­u­ally pro­duces three dis­tinct asex­ual stages, a mother sporo­cyst and two sub­se­quent re­dial stages over the course of a month (Sorensen and Minchella, 1998). The final re­dial pro­duces in­fec­tive free liv­ing cer­caria for 25 to 28 days (Kanev, 1994). The cer­caria exits the pri­mary in­ter­me­di­ate host and in­fects a sec­ondary in­ter­me­di­ate host.

Cer­cariae: The ini­tialy free-liv­ing form in­fects an aquatic sec­ondary in­ter­me­di­ate host within three to six hours. This host can be var­i­ous pul­monate and proso­branch snails, fresh­wa­ter mus­sels (Union­idae), frogs, and fresh­wa­ter tur­tles (Tes­tundines) (Kanev, 1994). In the host, cer­caria asex­u­ally pro­duce metac­er­cariae (Sorensen and Minchella, 1998).

Metac­er­cariae: This stage be­comes in­fec­tive within one to two days (Kanev, 1994). It re­mains in this stage until the sec­ondary in­ter­me­di­ate host has been eaten by the de­fin­i­tive ver­te­brate host, usu­ally a bird. Once in­gested, metac­er­cariae de­velop into her­maph­ro­ditic adults (Sorensen and Minchella, 1998). (Kanev, 1994; Sorensen and Minchella, 1998)

Re­pro­duc­tion

Adult Echi­nos­toma rev­o­lu­tum are her­maph­ro­dites, and pro­duce both self-fer­til­ized and cross-fer­til­ized eggs once in the de­fin­i­tive host. We have no in­for­ma­tion on mat­ing be­hav­ior or mat­ing sys­tems in this species. (Kanev, 1994; Sorensen and Minchella, 1998)

This species re­pro­duces asex­u­ally at two stages in its life cycle. Sporo­cysts and re­diae, both pro­duce large num­bers of off­spring asex­u­ally, re­sult­ing in hun­dreds or thou­sands of cer­carie gen­er­ated from a sin­gle par­ent miracid­ium in­fect­ing a snail. Adults worms are her­maph­ro­ditic and self- and cross-fer­til­ize.

'Echi­nos­tome Echi­nos­toma par­a­sitism peaks in the late sum­mer and wanes through­out the win­ter (Sorensen and Minchella, 1998).

The trema­tode, E. rev­o­lu­tum, has a com­plex three-host life cycle. Adult E. rev­o­lu­tum use avian species, pri­mar­ily wa­ter­fowl as the de­fin­i­tive host (Sorensen and Minchella, 1998). Adults are her­maph­ro­dites and live four to eight weeks. Adults begin to pro­duce and re­lease many self fer­til­ized eggs ten days after in­fect­ing the de­fin­i­tive host (Kanev, 1994). Adults after 14 days con­tain at least 50 eggs (Humphries et at., 1997). Eggs are passed by feces of the de­fin­i­tive host (Sorensen and Minchella, 1998). (Humphries, et al., 1997; Kanev, 1994; Sorensen and Minchella, 1998)

  • Breeding interval
    Echinostome parasitism peaks in the late summer and wanes throughout the winter
  • Range gestation period
    9 to 12 days
  • Average gestation period
    10-12 days

There is no parental in­vest­ment be­yond the lim­ited pro­vi­sion­ing of eggs.

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning

Be­hav­ior

Miracidia and cer­cariae are ac­tive host-seek­ing lar­vae that swim. The other stages of this species can move within their hosts, but do not leave them. (Bau­doin, 1975; Brown, et al., 1988; Sorensen and Minchella, 1998)

Com­mu­ni­ca­tion and Per­cep­tion

Miracid­ium are are pos­i­tively pho­to­tac­tic. Cer­cariae are neg­a­tively pho­to­tac­tic (Kanev, 1994). (Kanev, 1994)

Food Habits

Sporo­cysts lack am­bu­la­tory mus­cu­la­ture and ab­sorb pri­mary in­ter­me­di­ate host nu­tri­ents via their tegu­ment. Re­diae have a mus­cu­lar phar­ynx and prim­i­tive gut. Re­diae ac­tively con­sume and di­gest pri­mary in­ter­me­di­ate host tis­sues while mov­ing through­out the in­fected host (Sorensen and Minchella, 1998). (Sorensen and Minchella, 1998)

Pre­da­tion

We have no in­for­ma­tion on par­tic­u­lar preda­tors of this species. It is likely that the host-seek­ing stages (miracidia, cer­cariae) are con­sumed by preda­tors that eat zoo­plank­ton. This species de­pends on pre­da­tion of its in­ter­me­di­ate host to enter its de­fin­i­tive avian hosts.

Ecosys­tem Roles

In­fec­tion of Lym­naea elodes by E. rev­o­lu­tum sig­nif­i­cantly af­fects growth, fe­cun­dity, and sur­vival rates (Sorensen and Minchella, 1998). Snail mor­tal­ity be­tween zero and four weeks post in­fec­tion can be at­trib­uted to an in­crease in en­er­getic de­mands and star­va­tion, while snails four to seven weeks post in­fec­tion die from tis­sue de­gre­da­tion (Sorensen and Minchella, 1998).

At five weeks post in­fec­tion E. rev­o­lu­tum pathol­ogy in­volves de­struc­tion of the di­ges­tive gland and ovotestis (Sorensen and Minchella, 1998). This type of par­a­sitic cas­tra­tion along with re­duced nu­tri­ents re­sults in a re­duc­tion in snail egg pro­duc­tion. It is pro­posed by Sousa (1983) that gi­gan­tism will occur in trema­tode in­fected mol­lusc species be­cause ex­cess host en­ergy re­serves are made avail­able via par­a­sitic cas­tra­tion.

Brown et al. (1988) and Sorensen and Minchella (1998) both demon­strate a cor­re­la­tion be­tween in­creased snail size and trema­tode in­fec­tion. E. rev­o­lu­tum in­fec­tion tends to cause gi­gan­tism in lym­naea species. In 1975, Bau­doin pre­sented hy­pothe­ses to ex­plain the cor­re­la­tion be­tween host size and preva­lence of in­fec­tion. These hy­pothe­ses in­cluded three basic mech­a­nisms in­clud­ing in­creased host growth rates, host mor­tal­ity rates, and host size-spe­cific pref­er­ences of par­a­sites. It is pro­posed that a com­bi­na­tion of mul­ti­ple hy­pothe­ses will re­sult in gi­gan­tism of the host (Sorensen and Minchella, 1998). (Bau­doin, 1975; Brown, et al., 1988; Sorensen and Minchella, 1998)

Species Used as Host

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

In In­done­sia, Suhardono et al. (2006) have shown that E. rev­o­lu­tum will act com­pet­i­tively to in­fect Lym­naea ru­big­i­nosa. L. ru­big­i­nosa is more com­monly in­fected by Fas­ci­ola gi­gan­tica. L. ru­big­i­nosa in­fected with F. gi­gan­tica causes fas­ci­olo­sis in cat­tle stocks feed­ing on har­vested rice crop in­fested with the snails. E. rev­o­lu­tum will com­pete with F. gi­gan­tica, and when suc­cess­ful, pre­vents F. gi­gan­tica from in­fect­ing L. ru­big­i­nosa (a nec­es­sary stage in its life cycle). In­hi­bi­tion of F. gi­gan­tica pre­vents fur­ther life stages and con­se­quently pre­vents par­a­sitic in­fec­tion of cat­tle. E. rev­o­lu­tum will oc­cupy the in­ter­me­di­ate host (L. ru­big­i­nosa) but will not in­fect the cat­tle feed­ing on the rice crop. (Suhardono, et al., 2006)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Worms in the genus Echi­nos­toma have been known to in­fect hu­mans who have eaten raw snails or other mol­luscs.

Con­ser­va­tion Sta­tus

The world-wide pop­u­la­tion size of this species is un­known. It has not been con­sid­ered for con­ser­va­tion sta­tus by any agency.

Con­trib­u­tors

Michael Ko­rt­bawi (au­thor), Rut­gers Uni­ver­sity, Rosiane Les­per­ence (au­thor), Rut­gers Uni­ver­sity, Natasha Lloyd (au­thor), Rut­gers Uni­ver­sity, Alexa Mar­tinez (au­thor), Rut­gers Uni­ver­sity, David V. Howe (ed­i­tor), Rut­gers Uni­ver­sity, George Ham­mond (ed­i­tor), An­i­mal Di­ver­sity Web Staff.

Glossary

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.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

asexual

reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents

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.

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).

chemical

uses smells or other chemicals to communicate

diapause

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.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

freshwater

mainly lives in water that is not salty.

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.

internal fertilization

fertilization takes place within the female's body

iteroparous

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).

marsh

marshes are wetland areas often dominated by grasses and reeds.

metamorphosis

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.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

parasite

an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

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.

visual

uses sight to communicate

Ref­er­ences

Bau­doin, M. 1975. Host cas­tra­tion as a par­a­sitic strat­egy. Evo­lu­tion, 29: 335-352.

Brown, K., B. Leathers, D. Minchella. 1988. Trema­tode preva­lence and the pop­u­la­tion dy­nam­ics of fresh­wa­ter pond snails. Amer­i­can Mid­land Nat­u­ral­ist, 120: 289-301.

Dim­itrov, V., I. Kanev, R. Sorensen, M. Alx­ex­iev, M. Nestorov, V. Radev. 1999. Stud­ies on the ar­gen­tophilic struc­tures of two pop­u­la­tions of Echi­nos­toma rev­o­lu­tum (Frol­ich, 1802) (Trema­toda:Echi­nos­tom­ati­dae) miracidia. Ex­per­i­men­tal Pathol­ogy and Par­a­sitol­ogy, 3: 3-6.

Humphries, J., A. Reddy, B. Fried. 1997. In­fec­tiv­ity and Growth of Echi­nos­toma rev­o­lu­tum (Froelich, 1802) in the Do­mes­tic Chick. In­ter­na­tional Jour­nal for Par­a­sitol­ogy, 27/1: 129-130.

Kanev, I., B. Fried, V. Dim­itrov, V. Radev. 1995. Re­descrip­tion of Echi­nos­toma triv­o­lvis (Cort, 1914) with a dis­cus­sion on its iden­tity. Sys­tem­atic Par­a­sitol­ogy, 32: 61-71.

Kanev, I. 1994. Life-cy­cle, de­lim­i­ta­tion and re­descrip­tion of Echi­nos­toma rev­o­lu­tum (Froelich, 1802) (Trema­toda: Echi­nos­tom­ati­dae). Sys­tem­atic Par­a­sitol­ogy, 28: 125-144.

Sorensen, R., I. Kanev, B. Fried, D. Minchella. 1997. The oc­cur­rence and iden­ti­fi­ca­tion of Echi­nos­toma rev­o­lu­tum from North Amer­i­can Lym­naea elodes snails. Jour­nal of Par­a­sitol­ogy, 83(1): 169-170.

Sorensen, R., D. Minchella. 1998. Par­a­site in­flu­ences on host life his­tory: Echi­nos­toma rev­o­lu­tum par­a­sitism of Lym­naea elodes snails. Oe­colo­gia, 115: 188-195.

Suhardono, , J. Roberts, D. Cope­man. 2006. Bi­o­log­i­cal con­trol of Fas­ci­ola gi­gan­tica with Echi­nos­toma rev­o­lu­tum. Vet­eri­nary Par­a­sitol­ogy, 140: 166-170.