View source for Fascioloides magna

{{Taxobox
| color = pink
| name = Giant liver fluke
| image = F. magna adult.jpg
| regnum = [[Animal]]ia
| phylum = [[Platyhelminthe]]s
| classis = [[Trematoda]]
| subclassis = [[Digenea]]
| ordo = [[Echinostomida]]
| familia = [[Fasciolidae]]
| genus = ''[[Fascioloides]]''
| binomial = ''Fascioloides magna''
| binomial_authority = Bassi, [[1875]]
}}

{{CMG}}



'''''Fascioloides magna''''' (Bassi 1875), also known as '''giant liver fluke''', '''large American liver fluke''' or '''deer fluke''', is an important parasite of a variety of wild and domestic [[ruminant]]s in North America and Europe. Adult flukes occur in the liver of the definitive host and feed on blood. Mature flukes measure 4 to 10 cm in length × 2 to 3.5 cm in width, and have an oval dorso-ventrally flattened body with oral and [[ventral]] [[sucker]]. The flukes are reddish-brown in colour and are covered by [[tegument]]. Similarly to that in other [[digenea]]n [[trematode]]s, the life cycle includes [[intramolluscan phase]] in snails.<ref name=erhardova71>Erhardová-Kotrlá, B., 1971. The occurrence of ''Fascioloides magna'' (Bassi, 1875) in Czechoslovakia. Academia, Prague, 155 pp.</ref><ref name=pybus>Pybus, M.J., 2001. Liver flukes. In: Samuel, W.M., Pybus, M.J., Kocan, A.A. (eds.), Parasitic diseases in wild mammals, Iowa State Press, Iowa City, pp 121–149.</ref>

== History ==
''Fascioloides magna'' is essentially of North American origin but the parasite was introduced into Europe with imported game animals at the second half of the 19th century. In spite of being native to North America the fluke was first described in [[Italy]].<ref name=swales35> Swales, W.E., 1935. The life cycle of ''Fascioloides magna'' (Bassi, 1875), the large liver fluke of ruminants in Canada with observations on the bionomics of the larval stages and the intermediate hosts, pathology of fascioloidiasis magna, and control measures. Canadian Journal of Research 12, 177–215.</ref> In 1875, [[Bassi]] observed massive deaths of red deer in [[the Royal Park]] near [[Torino]], Italy. The signs were similar to well known [[fasciolosis]] in sheep. He named it ''Distomum magnum''. The author believed that the parasite was introduced into the park in wapiti imported from USA in 1865.<ref name=Bassi75>Bassi, R., 1875. Sulla cachessia ittero-verminosa, o marciaia, causata dal Distomum magnum. Medico Veterinaria Torino, S.4, v.4 (11-12), 497–515.</ref> Most workers did not accept Bassi’s species because of his poor description. From 1882 to 1892, the fluke was recorded from different areas of the United States and described separately by many authors. Later, Stiles (1894) pointed out that the American findings are identical with species described previously by Bassi. Stiles made a complete morphological description of the adult fluke and named it ''Fasciola magna'' (Bassi 1875) Stiles 1894.<ref name=swales35/> In 1917, Ward showed that owing to the lack of the distinct [[anterior]] [[cone]] and the fact that [[vitellaria]] are confided to the region ventral to the [[intestinal branches]], he established a new [[genus]] ''Fascioloides'' and rename it to ''Fascioloides magna'' (Bassi 1875) Ward 1917.<ref>Ward, H.B., 1917. On the structure and classification of North American parasitic worms. Journal of Parasitology 4, 1–12.</ref> In 1895, Stiles suggested that the life cycle of the fluke is very similar to [[Fasciola hepatica]], i.e. it includes an aquatic snail as an intermediate host. He gave a comparative description of the egg and [[miracidium]] of the fluke.<ref>Stiles, C.W., 1895. The anatomy of the large American fluke (''Fasciola magna'') and a comparison with other species of the genus ''Fasciola'', s. str. J Comp Med Vet Arch 16, 139–147, 213–222, 277–282.</ref> However, first reported intermediate hosts of ''F. magna'' were not published until 1930’s. The complete life cycle of ''F. magna'', including a description of all the larval stages, was described by Swales (1935) in Canada <ref name=swales35/>.

== Life cycle ==
[[Image:F. magna egg.jpg|left|thumb|150px|The egg of ''F. magna''.]]The life cycle of ''F. magna'' is relatively complex and is similar to the development of the related fluke, ''F. hepatica''. A detailed account of the ''F. magna'' life cycle was given by Swales (1935), Erhardová-Kotrlá (1971), and reviewed by Pybus (2001).<ref name=swales35/><ref name=erhardova71/><ref name=pybus/>[[Image:Fascioloides magna cercariae.jpg|middle|thumb|200px|The cercariae of ''F. magna'' shedded from the snail.]]Adult flukes occur in pairs or groups within a fibrous [[capsule]] in the liver parenchyma of the definitive host. Mature flukes release eggs which are collected in the cavity of the capsule. The capsule contains a great mass of eggs and has duct connections to bile ducts. The eggs are passed together with bile into the bile collecting system, enter the small intestine, and leave the definitive host along with the faeces. The eggs which are passed out in the faeces into the environment are undeveloped and undergo [[embryonation]] outside the host. Several physical-chemical factors, especially temperature, [[humidity]] and [[oxygen tension]], are known to influence embryonation. During the embryonation of the egg, a larva called a miracidium develops from germinal cells. Fully developed miracidium releases the [[operculum]] of the egg using several proteases. The embryonation period varies from 27 to 44 days in natural conditions. Ciliated miracidia hatch in water and actively seek suitable intermediate hosts that are freshwater snails from family [[Lymnaeidae]]. After attaching to a suitable snail host, the miracidium penetrates into the snail body. After shedding its ciliated cell layer it is called a [[sporocyst]]. The sporocysts are found in the foot, the snail body, digestive glands, reproductive organs, and in the [[pulmonary sac]] of the snail. The sporocysts contain germinal cells that give rise to 1-6 [[mother rediae]]. Developed mother rediae are released from the sporocyst and migrate into digestive glands, renal organ, reproductive organs, and pulmonary sac of the snail body. Each mother redia can produce up to 10 [[daughter rediae]]. However, only 3 to 6 daughter rediae complete their development and leave the mother rediae. In turn, each daughter redia may produce 1-6 [[cercaria]]e in experimentally infected snails and 16-22 cercariae under natural conditions. Cercariae emerge from the rediae and mature usually in digestive glands of the snail. Mature cercarie spontaneously emerge from the snail host and swim actively in water for up to two hours before encysting on vegetation. After encystment the flukes are called metacercariae. Development within the snail takes 40 to 69 days depending upon the temperature and the species of snail. The definitive host ingests vegetation containing the metacercariae. In the stomach and the intestine, the metacercariae are stimulated to emerge from the cyst ([[excystation]]). Newly excysted juvenile flukes penetrate the wall of the intestine and migrate in the abdominal cavity. Juvenile flukes penetrate the [[Glisson’s capsule]] of the liver and continue migrating in the liver tissue. Rarely juvenile flukes penetrate other organs, such as lungs or kidneys. In these organs, however, flukes do not survive and not attain maturity. In the liver, flukes migrate within the parenchyma to search another fluke. If the fluke meet another one, they stop moving, and the fibrous capsule is formed around them. In the capsule, the parasite completes its development and starts egg-laying. [[Prepatent period]] varies 3-7 months and is dependent on host species. Adult ''F. magna'' can survive in the liver of the host up to 7 years.

== Distribution == 
Currently, ''F. magna'' occurs only in North America and Europe where suitable [[habitat]] exists and susceptible intermediate hosts are found. However, sporadic works reported unique appearance of the fluke in other continents. ''F. magna'' was found in imported animals in South Africa, Australia and Cuba. In all cases, infected animals (brahman heifer, ox, and [[elk]], respectively) were imported from USA or Canada.<ref name=spakulova>Špakulová, M., Rajský, D., Sokol, J., Vodňanský, M., 2003. Giant liver fluke (''Fascioloides magna''), an important liver parasite of ruminants. Parpress, Bratislava, 61 pp.</ref> 

=== North America ===
During the 20th century, ''F. magna'' was reported in these American states: Arkansas, California, Colorado, Illinois, Iowa, Kansas, Louisiana, Michigan, Minnesota, Montana, New York, Oklahoma, Oregon, South Carolina, Texas, Washington, and Wisconsin. In Canada, the fluke was reported in Alberta, British Columbia, Ontario, and Quebec.<ref name=swales35/><ref name=pybus/> Currently, ''F. magna'' is enzootic in five major areas: (1) the [[Great Lakes]] region; (2) the Gulf coast, lower Mississippi, and southern Atlantic seaboard; (3) northern Pacific coast; (4) the Rocky Mountain trench; and (5) northern Quebec and Labrador. However, within these broad ranges, actual presence of giant liver flukes varies from locally abundant to locally absent.<ref name=pybus/> 
=== Europe ===
''Fascioloides magna'' was first reported by Bassi in Torino, Italy. In spite of Bassi’s work, no other data concerning the occurrence of F. magna in Europe were reported until 1930’s <ref name=swales35/>. In the [[Czechoslovakia|Czech]] territory, Ullrich reported the first appearance of ''F. magna ''in fallow deer as late as 1930.<ref name=Ullrich>Ullrich, K., 1930. Über das Vorkommen von seltenen oder wenig bekannten Parasiten der Säugetiere und Vögel in Böhmen und Mähren. Prager Archiv Tiermedicine 10, A (1/2), 19–43.</ref> At the same time, Salomon (1932) diagnosed the fluke in one hunted [[red deer]] near [[Görlitz]] (Saxony) in Germany. Other isolated findings of the fluke were recorded in Italy and Poland. From 1948 till 1961, sporadic occurrence of the parasite in red deer (''Cervus elaphus''), [[fallow deer]] (''Dama dama'') and [[roe deer]] (''Capreolus capreolus'') were reported by several authors in former [[Czechoslovakia]]. However, all reports were published on the basis of incident discoveries in hunted deer and no massive infections were documented <ref name=erhardova71/>.
In 1960’s, a number of ''F. magna'' outbreaks in [[cervid]]s were reported in some areas of former Czechoslovakia. The prevalence of infection varied from 70 to 80 % in red deer and maximum parasite burden was 144 worms. In addition, sudden deaths were documented in free or game ranging deer.<ref name=erhardova71/> The highest mortality was reported in free ranging roe deer in Písek County in the [[South Bohemia]] of former [[Czechoslovakia]]. In the same region, moreover, the parasite was found in livers of slaughtered cattle.<ref name=zahor65>Záhoř, Z., 1965. Výskyt velké motolice (''Fascioloides magna'' Bassi, 1875) u srnčí zvěře. Veterinářství 15, 322–324.</ref><ref>Záhoř, Z., Prokš, C., Vítovec, J., 1968. Morfologie změn způsobených velkou motolicí (''Fascioloides magna'', Bassi 1875) u skotu. Veterinary Medicine (Praha) 13, 369–375.</ref>. Erhardová-Kotrlá (1971) confirmed red deer, fallow deer and roe deer as main definitive hosts of ''F. magna'' in Europe. In 1960’s, ''F. magna'' was enzootic in former Czechoslovakia in following four major areas: (1) [[České Budějovice]] and [[Třeboň]] county, including [[Nové Hrady]] Mountains; (2) the area along the [[Vltava]] River on the Vltava-Týn hills near [[Hluboká]] and [[Bechyně]]; (3) [[Písek]] and Milevsko county; (4) the [[Brdy]] mountains and the [[Hřebeny]] mountains.<ref name=erhardova71/> In following years, ''F. magna'' was only reported from these areas. Recently, geographical distribution of ''F. magna'' in cervids was determined in the [[Czech Republic]]. The giant liver fluke was confirmed in the same areas as reported in 1960’s. However, seven new endemic areas of ''F. magna'' were discovered suggesting that the parasite is spreading in the Czech Republic. Moreover, the appearance of ''F. magna'' in the [[Šumava]] Mountains has epizootiological importance due to possibility of spread of the parasite into the German territory ([[Bavaria]]).<ref name=novo07a>Novobilský, A., Horáčková, E., Hirtová, L., Modrý, D., Koudela, B., 2007. The giant liver fluke ''Fascioloides magna'' (Bassi, 1875) in cervids in the Czech Republic and potential of its spreading to Germany. Parasitology Research 100, 549–553.</ref> During the last few years, a new European enzootic area has established in the [[Danube]] watershed in Central Europe. In 1988, ''F. magna'' was isolated from a 3-year old red deer female found dead near the [[Gabčíkovo]] water plant at the Danube River in Slovakia. The parasite has spread through whole Slovakian Danube watershed.<ref name=spakulova/>
Soon after the Slovakian first report, ''F. magna'' was found in red deer in Hungarian parts of Danubian floodplain forests. The prevalence reported by the same authors was up to 90 %. ''F. magna'' infection of cervids is a considerable problem in northern part of Hungary ([[Szigetköz]]) and the southern Danubian territory in the [[Gemenc]] area.<ref name=spakulova/> Since the autumn of 2000, ''F. magna'' has been found in Austrian territory, east of [[Vienna]]. In years 2000-2001, the prevalence of the giant liver fluke in red deer in Austrian parts of Danube (east of Vienna) was 66.7 %.<ref name=ursprung>Ursprung, J., Joachim, A., Prosl, H., 2006. Epidemiology and control of the giant liver fluke, ''Fascioloides magna'', in a population of wild ungulates in the Danubian wetlands east of Vienna. Berliner und Müncher Tiermedicine Woch 119, 316–323.</ref> In January 2000, the giant liver fluke was diagnosed in hunted red deer in [[Baranja]] region in eastern [[Croatia]]. The parasite was probably introduced into Baranja region by natural deer migration from neighbouring Hungary.<ref>Marinculić, A., Dźakula, N., Janicki, Z., Hardy, Z., Lucinger, S., Zivićnjak, T., 2002. Appearance of American liver fluke (''Fascioloides magna'', Bassi, 1875) in Croatia – a case report. Veterinarski Arhiv 72, 319–325.</ref> Regarding the origin of ''F. magna'' enzootic area in the Danube River watershed, it is essential to point out that cervids were not introduced into these localities, neither recently nor in the past. Origin of the ''F. magna'' population in Danubian floodplain forests in Central Europe remains therefore unclear.<ref name=spakulova/>

== Definitive hosts ==
[[Image:White-tailed deer.jpg|thumb|280px|White-tailed deer - a typical definitive host of the giant liver fluke]]Natural infections of ''F. magna'' occur primarily in cervids and bovids. Although many species are susceptible to infection, only a few cervid species contribute significantly to maintaining populations of the fluke.<ref name=pybus/> In North America, the common definitive hosts of the giant liver fluke are wapiti (''Cervus elaphus canadensis''), [[white-tailed deer]] (''Odocoileus virginianus'') and [[caribou]] (''Rangifer tarandus'').<ref name=foreyt76>Foreyt, W.J., Todd, A.C., 1976. Development of the large American liver fluke, ''Fascioloides magna'', in white-tailed deer, cattle, and sheep. Journal of Parasitology 62, 26–32.</ref><ref name=pybus/> In Europe, ''F. magna'' occurs commonly in red deer (''Cervus elaphus''), fallow deer (''Dama dama'') and roe deer (''Capreolus capreolus'').<ref name=erhardova71/> Domestic ruminants are also susceptible to natural infection with ''F. magna''. However, the infection is not patent, and domestic ruminants do not contribute to the propagation of the parasite in the environment.<ref name=swales36>Swales, W.E., 1936. Further studies on ''Fascioloides magna'' (Bassi, 1875) Ward, 1917, as a parasite of ruminants. Canadian Journal of Research 14, 83–95</ref> In North America, the giant liver fluke is commonly found in cattle, sheep and goats in areas where ''F. magna'' is enzootic in deer.<ref name=foreyt76/> In contrast, ''F. magna'' occurs rarely in domestic ruminants in Europe.<ref name=novo07a/>. The list of all natural definitive hosts of ''F. magna'' is presented in '''Table'''.

The only indigenous primary definitive host of ''F. magna'' is white-tailed deer. This species has been parasitized by the fluke for the longest time in historical context. Wapiti and caribou are of Eurasian origin and entered North America during the [[Pleistocene]] epoch, and overlapped with white-tailed deer in some parts of North America. They might have encountered ''F. magna'' in these shared biotopes.<ref name=pybus/>
{{-}}
{| class="wikitable"
! style="width:30%" |Common name of species
! style="width:30%" |Latin name of species
! style="width:10%" |References
|-
! style="text-align:left;white-space:nowrap;font-weight:bold"|'''NORTH AMERICA'''
! style="text-align:left;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Bison]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Bison bison''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Cameron, A.E., 1923. Notes on buffalo: Anatomy, pathological conditions, and parasites. Vet J 79, 331–336.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Black-tailed deer]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Odocoileus hemionus columbianus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Hadwen, S., 1916. A new host for Fasciola magna, Bassi, together with observations on the distribution of Fasciola hepatica, L. in Canada. J Am Vet Med Assoc 49, 511–515.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Caribou]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Rangifer tarandus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Cattalo]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Bos taurus'' × ''Bison bison''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Cattle]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Bos taurus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Francis, M., 1891. Liver flukes. Texas Agr Sta Bull 18, 135–136.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Collared peccary]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Dicotyles tajacu''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Samuel, W.M., Low, W.A., 1970. Parasites of the collared peccary from Texas. J Wildl Dis 6, 16–23.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Goat]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Capra hircus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Olsen, O.W., 1949. White-tailed deer as a reservoir host of the large American liver fluke. Vet Med 44, 26–30.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Horse]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Equus caballus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>McClanahan, S.L., Stromberg, B.E., Hayden, D.W., Averbeck, G.A., Wilson, J.H., 2005. Natural infection of a horse with Fascioloides magna. J Vet Diagn Invest 17, 382–385.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Llama]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Lama glama''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Conboy, G.A., O´Brien, T.D., Stevens, D.L., 1988. A natural infection of Fascioloides magna in a llama (Lama glama). J Parasitol 74, 345–346.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Moose]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Alces alces''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Kingscote, A.A., 1950. Liver rot (fascioloidiasis) in ruminants. Can J Comp Med 14, 203–208.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Mule deer]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Odocoileus hemionus hemionus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Pig]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Sus scrofa'' var. ''domesticus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Migaki, G., Zinter, D.E., Garner, F.M., 1971. Fascioloides magna in the pig-3 cases. Am J Vet Res 32, 1417–1421.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Sheep]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Ovis aries''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Wapiti]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Cervus elaphus canadensis''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[White-tailed deer]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Odocoileus virginianus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Wild boar]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Sus scrofa''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Foreyt, W.J., Todd, A.C., Foreyt, K., 1975. Fascioloides magna (Bassi, 1875) in feral swine from southern Texas. J Wildl Dis 11, 554–559.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Yak]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Bos grunniensis''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:bold"|'''EUROPE'''
! style="text-align:left;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Blue bull]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Bosephalus tragocamelus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Bassi75/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|Cattle
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Bos taurus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Bassi75/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Fallow deer]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Dama dama''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Ullrich/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|Goat
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Capra hircus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Bassi75/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|Horse
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Equus caballus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Balbo87>Balbo, T., Lanfranchi, P., Rossi, L., Meneguz, P.G., 1987. Health management of a red deer population infected by ''Fascioloides magna'' (Bassi, 1875) Ward, 1917. Ann Fac Med Vet Torino 32, 23–33.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Red deer]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Cervus elaphus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Bassi75/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Roe deer]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Capreolus capreolus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=zahor65/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Sambar]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Cervus unicolor''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Bassi75/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|Sheep
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Ovis aries''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Bassi75/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Sika deer]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Sika nippon''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=erhardova71/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|White-tailed deer
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Odocoileus virginianus''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=erhardova71/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|[[Wild boar]]
! style="text-align: left;white-space:nowrap;font-weight:normal"|''Sus scrofa''
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=Balbo87/>
|-
|}

== Clinical signs, pathology and pathophysiology ==
According to several American authors, three types of definitive host exist: <ref name=pybus/><ref name=swales35/><ref name=foreyt76/> 
* (1) '''definitive hosts'''
* (2) '''dead-end hosts'''
* (3) '''aberrant hosts'''
Pathology of ''F. magna'' infection varies according to host type but some features are shared by all three types. Primary lesions usually occur in the liver and are associated with mechanical damage due to migrating juvenile flukes or fibrous encapsulation of sedentary adult flukes.<ref name=pybus/> The most common feature of ''F. magna'' infection is black pigmentation in abdominal or thoracic organs, especially in the liver.<ref name=swales35/> The hematin pigment is produced by flukes as a byproduct of feeding on blood.<ref name=campbell>Campbell, W.C., 1960. Nature and possible significance of the pigment in fascioloidiasis. Journal of Parasitology 46, 769–775.</ref><ref>Blažek, K., Gilka, F., 1970. Contribution to the knowledge of the pigment found in infection with ''Fascioloides magna''. Folia Parasitologica 17, 165–170.</ref> Pigment within tissues is a result of migrating of juvenile flukes and it accumulates within hepatic cells without resorption.<ref name=campbell/>

=== (1) Definitive hosts ===
[[Image:F.magna fibrous capsule.JPG|thumb|250px|The fibrous capsule in the liver parenchyma of red deer infected with ''F. magna'']]Definitive hosts are primarily New World and some Old World cervids.<ref name=pybus/> In definitive hosts, flukes are encapsulated in thin-walled fibrous capsules communicating to the bile system. The eggs are passed through the bile system, enter the small intestine, and leave the host with faeces. Therefore, the infection is patent.<ref name=swales35/><ref name=swales36/> The capsules are a result of the defence response of the host to the parasite and are pathognomonic for ''F. magna'' infection. They contain two to five flukes, greyish-black fluid with eggs and cell detritus.<ref name=swales36/><ref name=pybus/> 

''F. magna'' infections in definitive hosts are usually subclinical.<ref name=pybus/> However, massive deaths caused by the fluke in red-, fallow- and roe deer were reported.<ref name=zahor65/><ref name=erhardova71/><ref>Novobilský, A., Horáčková, E., Koudela, B., 2005. Current distribution of the giant liver fluke ''Fascioloides magna'' in the Czech Republic. Proceedings of the 13th Helminthological Days Held at Ředkovec, Czech Republic, May 9-13th 2005. Helminthologia 42, 181–182.</ref> Lethargy, depression, weight loss and decreased quality of antlers can occur sporadically.<ref name=erhardova71/> In addition, nervous symptoms were observed very rarely. In the first case, urging motion followed by apathy was reported in one experimentally infected fallow deer.<ref name=er_blazek>Erhardová-Kotrlá, B., Blažek, K., 1970. Artificial infestation caused by the fluke ''Fascioloides magna''. Acta Veterinaria Brno 39, 287–295.</ref> Authors suggested that these symptoms were associated with [[hepatocerebral syndrome]]. Other author has observed partial paralysis in naturally infected wapiti caused by migrating juvenile flukes in the spinal cord.<ref>Sharma, A., 2002. Final diagnosis: ''Fascioloides magna'' in spinal cord. [http://www.addl.purdue.edu/newsletters/2002/fall/fall2002.pdf]</ref>
Biochemical and haematological profiles are little investigated in definitive hosts. A decrease of [[haemoglobin]], elevation of [[Gamma globulin|γ-globulins]], and increase of [[eosinophil]]s in serum was observed in experimentally infected white-tailed deer.<ref>Presidente, P.J., McCraw, B.M., Lumsden, J.H., 1980. Pathogenicity of immature ''Fascioloides magna'' in white-tailed deer. Canadian Journal of Comparative Medicine 44, 423–32.</ref><ref> Foreyt, W.J., Todd, A.C., 1979. Selected clinicopathologic changes associated with experimentally induced ''Fascioloides magna'' infection in white-tailed deer. Journal of Wildlife Diseases 15, 83–89.</ref>

=== (2) Dead-end hosts ===
Dead-end hosts are represented by large bovids, suids, llamas, horses and some Old World cervids. Infections in dead-end hosts are characterized by excessive fibrosis, thick-walled encapsulation of flukes within hepatic parenchyma, and black pigmentation of various tissues.<ref name=pybus/> Both afferent and efferent bile ducts are totally occluded and are marked by tracts of fibrous tissue. The eggs can not be passed into the bile system, and, therefore, the infection is not patent. In addition, flukes rarely mature in dead-end hosts probably due to strong immune response.<ref name=swales36/> Nevertheless, appearance of ''F. magna'' eggs in the faeces of single experimentally infected calf has been documented.<ref name=er_blazek/> Pathophysiology or clinical symptoms in dead-end hosts have been rarely studied. In cattle, significant elevations of eosinophil counts in periphery blood but only slight increases of AST and GGT have been observed.<ref name=conboy>Conboy, G.A., Stromberg, B.E., 1991. Hematology and clinical pathology of experimental ''Fascioloides magna'' infection in cattle and guinea pigs. Veterinary Parasitology 40, 241–255.</ref> While American authors have not observed any clinical symptoms in cattle<ref name=foreyt76/><ref name=conboy/>, anorexia and weight loss were recorded in naturally infected bulls in the former Czechoslovakia.<ref>Chroustová, E., Hůlka, J., Jaroš, J., 1980. Prevence a terapie fascioloidózy skotu bithionolsulfoxidem. Veterinary Medicine (Praha) 25, 557–563.</ref>

=== (3) Aberrant hosts ===
[[Image:F._magna_adhesion_and_fibrin_in_abdomen.jpg|thumb|250px|Necropsy of goat infetced with ''F. magna'': fibrin between liver and diaphragm]]Aberrant hosts of ''F. magna'' are sheep and goats.<ref name=swales35/><ref name= foreyt76/><ref>Olsen, O.W., 1949. White-tailed deer as a reservoir host of the large American liver fluke. Veterinary Medicine 44, 26–30.</ref> However, the course of infection is similar in guinea pigs<ref name=conboy/>, rabbits<ref name=swales35/>, bighorn sheep (''Ovis canadensis'')<ref>Foreyt, W.J., 1996. Susceptibility of bighorn sheep (''Ovis canadensis'') to experimentally-induced ''Fascioloides magna'' infections. Journal of Wildlife Diseases 32, 556–559.</ref> and chamois (''Rupicapra rupicapra'')<ref name=er_blazek/> that were infected experimentally. Infections in aberrant hosts are characterized by excessive wandering of juvenile flukes and death of the host.<ref name=pybus/> Aberrant hosts die usually within 6 months post-infection and the death is associated with acute peritonitis or extensive [[haemorrhage]] caused by migrating flukes.<ref name=pybus/><ref name=er_blazek><ref name=stromberg>Stromberg, B.E., Conboy, G.A., Hayden, D.W., Schlotthauer, J.C., 1985. Pathophysiologic effects of experimentally induced ''Fascioloides magna'' infection in sheep. American Journal of Veterinary Research 46, 1637–1641.</ref><ref name=foreyt80>Foreyt, W.J., Leathers, C.W., 1980. Experimental infection of domestic goats with ''Fascioloides magna''. American Journal of Veterinary Research 41, 883–884.</ref> In aberrant hosts, flukes do not mature and migrate until the host dies.<ref name=foreyt76/> Occasionally, a few flukes mature and eggs can be found in the faeces.<ref name=novo07b>Novobilský, A., Kašný, M., Mikeš, L., Kovařčík, K., Koudela, B., 2007. Humoral immune responses during experimental infection with ''Fascioloides magna'' and ''Fasciola hepatica'' in goats and comparison of their excretory/secretory products. Parasitology Research 101, 357–364.</ref><ref name=foreyt90>Foreyt, W.J., 1990. Domestic sheep as a rare definitive host of the large American liver fluke ''Fascioloides magna''. Journal of Parasitology 76, 736–739.</ref> Hepatic lesions in aberrant hosts generally include firm [[adhesion]]s of the liver to the [[Thoracic diaphragm|diaphragm]], black pigmentation, [[hematoma]]s, [[necrose]]s, and haemorrhagic tracts in which juvenile flukes are located <ref name=foreyt80/>. While a lack of fibrous capsules within hepatic parenchyma has been reported by several authors <ref name=pybus/><ref name=foreyt76/>, flukes in fibrous capsules have also been documented in sheep.<ref name=stromberg/> <ref name=swales36/> However, the wall of the capsule is different from those found in cervids and large bovids. The dominant feature is a diffuse fibrosis throughout the liver and haemorrhagic migratory tracts containing erythrocytes, black pigment, and cell detritus. The liver lesions are infiltrated by eosinophils, plasma cells, and pigment-laden macrophages.<ref name=stromberg/> 
Sheep and goats die acutely without any previous clinical signs.<ref name=foreyt76/><ref name=stromberg/>. Only elevation of eosinophils and slight increase of γ-globulins were observed in experimentally infected sheep.<ref name=stromberg/> Recently, several changes in biochemical and haematological profile have been documented in experimentally infected goats. The significant increase of GLDH ([[glutalaldehyde dehydrogenase]]) was recorded from 14 week after infection in goats experimentally infected with ''F. magna''.<ref>Novobilský, A., Pavlata, L., Mišurová, Ľ., Antoš, D., Koudela, B., 2006. Porovnání průběhu infekce ''Fascioloides magna'' a ''Fasciola hepatica'' u experimentálně infikovaných koz. Proceedings of the 7th Slovakian and Czech Parasitological Days, Modra-Harmónia, Slovakia, May 23-27th 2006, p 27.</ref>

== Intermediate hosts ==
[[Image:G. truncatula and R. peregra.jpg|250px|thumb|Intermediate hosts of ''F. magna'' in Europe – freshwater snails ''G. truncatula'' (up) a ''R. peregra'' (bellow).]]Since the presence of an intermediate host is essential to the completion of the life cycle, snails occupy the important role in the epidemiology of ''F. magna''. The intermediate hosts of the giant liver fluke belong to the family [[Lymnaeidae]]. In North America, a total of 10 lymnaeid snails were reported as intermediate hosts of ''F. magna''.<ref>Dunkel, A.M., Rognlie, M.C., Johnson, G.R., Knapp, S.E., 1996. Distribution of potential intermediate hosts for ''Fasciola hepatica'' and ''Fascioloides magna'' in Montana, USA. Veterinary Parasitology 62, 63–70.</ref> 6 of 10 North American snail species were found naturally infected and the other four were infected only under experimental conditions.<ref name=erhardova71/> In addition, the Australian species [[Lymnaea tomentosa tomentosa|''Austropeplea'' (''Lymnaea'') ''tomentosa'']] was exposed to the North American isolate of ''F. magna'' and the parasite was able to complete its development.<ref name=foreyt74>Foreyt, W.J., Todd, A.C., 1974. ''Lymnaea tomentosa'' from Australia, an experimental intermediate host of the large American liver fluke, ''Fascioloides magna''. Australian Veterinary Journal 50, 471–472.</ref> The most common North American natural snail hosts of the fluke are [[Fossaria modicella|''Fossaria'' (''Galba'') ''modicella'']], [[Stagnicola caperata|''Stagnicola'' (''Lymnaea'') ''caperata'']] and [[Fossaria bulimoides|''Fossaria'' (''Galba'') ''bulimoides techella'']]. In Europe, an intermediate host had not been known until 1960’s. At the beginning, Ślusarski assumed that ''[[Lymnaea stagnalis]]'' could act as an intermediate host of ''F. magna'' in Europe. His assumption, however, has been neither confirmed by positive findings in the field nor by experimental infection. In 1961, Dr. Erhardová described the life cycle of ''F. magna'' based on observations of experimentally and naturally infected snails. She confirmed that ''[[Galba truncatula]]'' is an intermediate host of the giant liver fluke in Europe.<ref name=erhardova71/> In later works, the author studied another lymnaeid species in the former Czechoslovakia. However, ''G. truncatula'' was repeatedly confirmed as the only snail host of ''F. magna''. In 1979, Chroustová reported successful experimental infection of [[Stagnicola palustris|''Stagnicola'' (''Lymnaea'') ''palustris'']] with ''F. magna''. She considered that this species might serve as an intermediate host of the fluke in the environment. Nevertheless, no naturally infected snails were found.<ref name=chroustova>Chroustová, E., 1979. Experimental infection of ''Lymnaea palustris'' snails with ''Fascioloides magna''. Veterinary Parasitology 5, 57–64.</ref> Recent studies indicate that another lymnaeid snail, ''[[Radix peregra]]'', may be also involved in the transmission of ''F. magna'' in Europe. This opinion is supported by successful experimental infection of ''R. peregra'' in the lab as well as by findings of naturally infected ''R. peregra'' in the environment <ref name=faltynkova>Faltýnková, A., Horáčková, E., Hirtová, L., Novobilský, A., Modrý, D., Scholz, T., 2006. Is ''Radix peregra'' a new intermediate host of ''Fascioloides magna'' (Trematoda) in Europe? Field and experimental evidence. Acta Parasitologica 51, 87–90.</ref> These findings suggested that the intermediate host spectrum of ''F. magna'' should be, similarly to North America, diverse in Europe. The list of intermediate hosts of ''F. magna'' is presented in following table.

{{-}}
{| class="wikitable"
! style="width:20%" |Snail species
! style="width:9%" |Naturally infected
! style="width:9%" |Experimentally infected
! style="width:15%" |Country
! style="width:5%" |Reference
|-
! style="text-align:left;white-space:nowrap;font-weight:bold"|NORTH AMERICA
! style="text-align:central;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Fossaria'' (''Galba'') ''bulimoides techella''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes 
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Sinitsin, D.F., 1930. A note on the life history of the large American liver fluke, ''Fasciola magna'' (Bassi). Science 72, 273–274.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Fossaria'' (''Galba'') ''modicella''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes 
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States, Canada
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Krull, W.H., 1934. The intermediate hosts of ''Fasciola hepatica'' and ''Fascioloides magna'' in the United States. N Am Vet. 15, 13-17.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Pseudosuccinea columella ''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States 
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Krull, W.H., 1934. The intermediate hosts of ''Fasciola hepatica'' and ''Fascioloides magna'' in the United States. N Am Vet. 15, 13-17.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Fossaria'' (''Galba'') ''parva''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes 
! style="text-align:central;white-space:nowrap;font-weight:normal"|Canada
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Stagnicola palustris nuttalliana''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|Canada
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=swales35/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Lymnaea stagnalis''
! style="text-align:central;white-space:nowrap;font-weight:normal"|no
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Wu, L.Y., Kingscote, A.A., 1953. A notes on "Lymnaea stagnalis" (L.) as a snail host for "Fascioloides magna" (Bassi, 1875) (Trematoda). J Parasitol 39, 568.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Stagnicola palustris''
! style="text-align:central;white-space:nowrap;font-weight:normal"|no
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Griffiths, H.J., 1955. "Stagnicola palustris" (Müller), an intermediate host for "Fascioloides magna" (Bassi, 1875) in Minnesota. J Parasitol 41, 115.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Stagnicola'' (''Lymnaea'') ''caperata''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes 
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref> Griffiths, H.J., 1959. "Stagnicola" ("Hinckleyia") "caperata" Say, a natural intermediate host for "Fascioloides magna" (Bassi, 1875), in Minnesota. J Parasitol. 45, 146.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Lymnaea ferruginea''
! style="text-align:central;white-space:nowrap;font-weight:normal"|no
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Dutson, V.J., Shaw, J.N., Knapp, S.E., 1967. Epizootiologic factors of ''Fascioloides magna'' (Trematoda) in Oregon and Southern Washington. Am J Vet Res. 124, 853-864.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Austropeplea'' (''Lymnaea'') ''tomentosa''
! style="text-align:central;white-space:nowrap;font-weight:normal"|no
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|Australia*
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=foreyt74/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Lymnaea umbrosa''
! style="text-align:central;white-space:nowrap;font-weight:normal"|no
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|United States
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Foreyt, W.J., Todd, A.C., 1978. Experimental infection of lymnaeid snails in Wisconsin with miracidia of ''Fascioloides magna'' and ''Fasciola hepatica''. J Parasitol 64, 1132-1134.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:bold"|EUROPE
! style="text-align:central;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
! style="text-align:central;white-space:nowrap;font-weight:normal"|
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Galba truncatula''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes 
! style="text-align:central;white-space:nowrap;font-weight:normal"|Czech Republic
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=erhardova71/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Stagnicola'' (''Lymnaea'') ''palustris''
! style="text-align:central;white-space:nowrap;font-weight:normal"|no
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|Czech Republic
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=chroustova/>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Omphiscola glabra''
! style="text-align:central;white-space:nowrap;font-weight:normal"|no
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes 
! style="text-align:central;white-space:nowrap;font-weight:normal"|France**
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref>Rondelaud, D., Novobilský, A., Vignoles, P., Treuil, P., Koudela, B., Dreyfuss, G., 2006. First studies on the susceptibility of ''Omphiscola glabra'' (Gastropoda: Lymnaeidae) from central France to ''Fascioloides magna''. Parasitol Res 98, 299-303.</ref>
|-
! style="text-align:left;white-space:nowrap;font-weight:normal"|''Radix peregra''
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|yes
! style="text-align:central;white-space:nowrap;font-weight:normal"|Czech Republic
! style="text-align:central;white-space:nowrap;font-weight:normal"|<ref name=faltynkova/>
|-
|}
(*) Snails originated from Australia infected with United States isolate of ''F. magna''<br />
(**) Snails originated from France infected with Czech isolate of ''F. magna''

== Diagnosis ==
While the eggs of ''F. magna'' resemble those of ''[[Fasciola hepatica|F. hepatica]]'', this similarity is of limited use; eggs usually are not passed in cattle and sheep. Recovery of the parasites at necropsy, as well as proper identification of ''F. hepatica'' or ''F. gigantica'' is necessary for definite diagnosis. When domestic ruminants and deer share the same grazing areas, the presence of disease due to ''F. magna'' should be kept in mind. Mixed infections with ''F. hepatica'' occur in cattle. 

== Control of ''F. magna'' and prevention ==
[[Image:Triclabendazole.png|thumb|250px|Formula of triclabendazole]] For control of fascioloidosis in wild ruminants, successful application of [[anthelminthic]]s in feed is necessary. The drug has to posses flavour and smell that do not prevent animals from eating of medicated feed. In addition, there should adequate therapeutic scope, i.e. span between therapeutic and minimal toxic dose. Therefore, only some of anthelminthics that are efficient in domestic ruminants have been tested in wild ruminants infected with ''F. magna''.<ref name=spakulova/> Several drugs, namely [[oxyclosanide]], [[rafoxanide]], [[albendazole]], [[diamphenetide]], [[closantel]], [[clorsulon]], and [[triclabendazole]], have been used in control of ''F. magna'' infection in cervids. However, the results have differed between different authors. Same in the case of ''F. hepatica'', triclabendazole seems to be most effective against ''F. magna''.<ref>Novobilský, A., Koudela, B., 2005. Treatment and control of ''Fascioloides magna'' infection in cervids – review. Veterinářství 55, 98–102.</ref> Fascioloidosis of cervids was successfully controlled with triclabendazole in USA <ref>Qureshi, T., Drawe, D.L., Davis, D.S., Craig, T.M., 1994. Use of bait containing triclabendazole to treat ''Fascioloides magna'' infections in free ranging white-tailed deer. Journal of Wildlife Diseases 30, 346–350.</ref>, Canada <ref>Pybus, M.J., Onderka, D.K., Cool, N., 1991. Efficacy of triclabendazole against natural infections of ''Fascioloides magna'' in wapiti. Journal of Wildlife Diseases 27, 599–605.</ref>, Austria <ref name=ursprung/>, and Croatia.<ref>Janicki, Z., Konjevic, D., Severin, K., 2005. Monitoring and treatment of ''Fascioloides magna'' in semi-farm red deer husbandry in Croatia. Veterinary Research Communications 29, 83–88.</ref> In contrast, rafoxanide is commonly used in treatment in Czech Republic <ref name=novo07a/> and Slovakia <ref name=spakulova/>. Nevertheless, recent studies suggested that use of rafoxanide in control of ''F. magna'' infection should be considered <ref name=novo07a/>. Unfortunetally, rafoxanide in commercial drug called Rafendazol Premix is the only registered drug for wild ruminants. Triclabendazole and others are produced as drugs for domestic animals and it can be used in free-living animals only with special permit.

== See also ==
* [[Fascioliasis]]
* ''[[Fasciola hepatica]]''

== References ==
{{Reflist}}

== External links ==
*[http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1680019 ''F. magna'' in Canada] 
*[http://www.vef.hr/vetarhiv/papers/2006-76-7-1.pdf Control of fascioloidosis in Croatia (PDF format)]
*[http://www.usask.ca/wcvm/herdmed/specialstock/elk/diseases/liverfluke.html ''F. magna'' and wapiti]
*[http://www.unbc.ca/nlui/wildlife_diseases_bc/liver_flukes.htm Liver flukes]
*[http://www.addl.purdue.edu/newsletters/2002/fall/fall2002.pdf Final diagnosis: ''Fascioloides magna'' in spinal cord (PDF format)] 
*[http://www.oie.int/eng/publicat/rt/2102/HAIGH.pdf Viral, parasitic and prion diseases of farmed deer and bison (PDF format)]


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