View source for Fasciolosis

{{Short description|Parasitic worm infection}}
{{cs1 config|name-list-style=vanc}}
{{About|the infection|the organism|Fasciola}}
{{Distinguish|Fasciolopsis}}
{{Infobox medical condition (new)
| name            = Fasciolosis
| synonyms        = Fascioliasis, fasciolasis, distomatosis, liver rot
| image           = Fasciola hepatica.JPG
| caption         = ''Fasciola hepatica''
| pronounce       =
| field           = [[Infectious disease]], [[hepatology]]
| symptoms        = Abdominal pain, nausea, yellow skin
| complications   = [[Pancreatitis]], [[anemia]]<ref name="CDCFasciola" />
| onset           =
| duration        =
| types           =
| causes          = ''[[Fasciola]]'' flatworms
| risks           = Eating raw [[watercress]]
| diagnosis       = [[Stool sample]]<ref>{{cite web| url = https://www.msdmanuals.com/professional/infectious-diseases/trematodes-flukes/fascioliasis | title= Fascioliasis - Infectious Diseases - MSD Manual Professional Edition | publisher = Richard D. Pearson | access-date = 18 August 2020 }}</ref>
| differential    =
| prevention      = Proper food preparation
| treatment       =
| medication      = [[Triclabendazole]]<ref name="CDCFasciola" />
| prognosis       =
| frequency       = 2 millions<ref name="CDCFasciola">{{cite web| url = https://www.cdc.gov/parasites/fasciola/ |title = CDC - Fasciola |access-date = December 31, 2018}}</ref>
| deaths          =
}}
<!-- Definitions and symptoms -->
'''Fasciolosis''' is a [[helminth|parasitic worm]] infection caused by the common liver fluke ''[[Fasciola hepatica]]'' as well as by ''[[Fasciola gigantica]]''. The disease is a plant-borne [[Trematoda|trematode]] [[zoonosis]],<ref name="Mas-Coma05">{{cite journal |vauthors=Mas-Coma S, Bargues MD, Valero MA |title=Fascioliasis and other plant-borne trematode zoonoses |journal=Int. J. Parasitol. |volume=35 |issue=11–12 |pages=1255–78 |date=October 2005 |pmid=16150452 |doi=10.1016/j.ijpara.2005.07.010 }}</ref> and is classified as a [[Neglected tropical diseases|neglected tropical disease]] (NTD).<ref name=Mansons/><ref name=":0">{{cite web|title=Neglected Tropical Diseases|url=https://www.cdc.gov/globalhealth/ntd/diseases/index.html|website=cdc.gov|access-date=28 November 2014|date=June 6, 2011}}</ref> It affects humans, but its main host is ruminants such as [[cattle]] and [[sheep]].<ref name=Mansons/> The disease progresses through four distinct phases; an initial incubation phase of between a few days up to three months with little or no symptoms; an invasive or acute phase which may manifest with: fever, malaise, abdominal pain, gastrointestinal symptoms, urticaria, [[anemia]], [[jaundice]], and [[respiratory symptoms]].<ref name="CDC - Fasciola - Treatment">{{Cite web|title = CDC - Fasciola - Treatment|url = https://www.cdc.gov/parasites/fasciola/treatment.html|website = www.cdc.gov|access-date = 2015-07-17}}</ref> The disease later progresses to a latent phase with fewer symptoms and ultimately into a chronic or obstructive phase months to years later.<ref name="Mas-Coma99">{{cite book |last=Mas-Coma |first=S |author2=Bargues MD |author3=Esteban JG  |chapter=Human fasciolosis.|editor=Dalton, JP |title=Fasciolosis |publisher=CABI Pub |location=Wallingford, Oxon, UK |year=1999 |pages=411–34 |isbn=0-85199-260-9 }}</ref><ref name="Esteb98">{{cite journal | last1 = Esteban | first1 = J.G. | last2 = Bargues | first2 = M.D. | last3 = Mas-Coma | first3 = S. | year = 1998 | title = Geographical distribution, diagnosis and treatment of human fascioliasis: a review | journal = Res. Rev. Parasitol | volume = 58 | pages = 13–42 }}</ref> In the chronic state the disease causes inflammation of the [[bile duct]]s, [[cholecystitis|gall bladder]] and may cause [[cholelithiasis|gall stone]]s as well as [[fibrosis]].<ref name="Mansons" /> While chronic inflammation is connected to increased cancer rates, it is unclear whether fasciolosis is associated with increased cancer risk.<ref name=Tsocheva>{{Cite web |publisher= Göteborgs universitetsbibliotek: Logga in via proxy |url = http://www.saske.sk/pau/helminthologia/2005_2/Tsocheva107.pdf |title= Fasciolosis and tumour growth |access-date= 2015-07-17}}</ref>

<!-- Cause and diagnosis-->
Up to half of those infected display no symptoms,<ref name=Mansons/> and diagnosis is difficult because the worm eggs are often missed in fecal examination.<ref name=Mansons>{{Cite book |title= Manson's Tropical Diseases |url = https://books.google.com/books?id=GTjRAQAAQBAJ&q=manson%2527s+tropical+infectious+diseases&pg=PA691-IA1 |publisher= Elsevier Health Sciences |date= 2013-10-26 |isbn= 9780702053061 |first1= Jeremy |last1= Farrar |first2= Peter |last2= Hotez |first3= Thomas |last3= Junghanss |first4= Gagandeep |last4= Kang |first5= David |last5= Lalloo |first6= Nicholas J. |last6= White}}</ref> The methods of detection are through fecal examination, parasite-specific antibody detection, or radiological diagnosis, as well as [[laparotomy]]. In case of a suspected outbreak it may be useful to keep track of dietary history, which is also useful for the exclusion of differential diagnoses.<ref name="Mansons" /> Fecal examination is generally not helpful because the worm eggs can seldom be detected in the chronic phase of the infection. Eggs appear in the feces first between 9–11 weeks post-infection. The cause of this is unknown, and it is also difficult to distinguish between the different species of fasciola as well as distinguishing them from [[Echinostoma|echinostomes]] and ''[[Fasciolopsis]]''.<ref name="Mansons" /> Most immunodiagnostic tests detect infection with very high sensitivity, and as concentration drops after treatment, it is a very good diagnostic method.<ref name="Mansons" /> Clinically it is not possible to differentiate from other [[Hepatobiliary diseases|liver and bile diseases]]. Radiological methods can detect lesions in both acute and chronic infections, while laparotomy will detect lesions and also occasionally eggs and live worms.<ref name="Mansons" />

<!-- Treatment-->
Because of the size of the parasite, as adult ''F. hepatica'': {{convert|20|–|30 |xx|13|mm |abbr=in}} or adult ''F. gigantica:'' {{convert|25|–|75 |xx|12|mm |abbr=in}}, fasciolosis is a big concern.<ref name="Mansons" /> The amount of symptoms depends on how many worms and what stage the infection is in. The death rate is significant in both cattle (67.55%) and goats (24.61%),<ref>{{cite journal |last1=Rahman |first1=A. K. M. A. |last2=Islam |first2=S. K. S. |last3=Talukder |first3=M. H. |last4=Hassan |first4=M. K. |last5=Dhand |first5=N. K. |last6=Ward |first6=M. P. |title=Fascioliasis risk factors and space-time clusters in domestic ruminants in Bangladesh |journal=Parasit Vectors |date=8 May 2017 |doi=10.1186/s13071-017-2168-7|pmc=5422951 |pmid=28482863 |volume=10 |issue=1 |page=228 |doi-access=free }}</ref> but generally low among humans.{{Citation needed |date= July 2015}} Treatment with [[triclabendazole]] has been highly effective against the adult worms as well as various developing stages.<ref name="Mansons" /><ref name="CDC - Fasciola - Treatment" /> [[Praziquantel]] is not effective, and older drugs such as [[bithionol]] are moderately effective but also cause more side effects. Secondary bacterial infection causing [[cholangitis]]  has also been a concern and can be treated with antibiotics, and [[Bacteremia#Consequences|toxaemia]] may be treated with [[prednisolone]].<ref name="Mansons" />

<!--Control, prevention and epidemiology -->
Humans are infected by eating watergrown plants, primarily wild-grown [[watercress]] in Europe or [[morning glory]] in Asia. Infection may also occur by drinking contaminated water with floating [[metacercariae|young fasciola]] or when using utensils washed with contaminated water.<ref name="Mansons" /> Cultivated plants do not spread the disease in the same capacity. Human infection is rare, even if the infection rate is high among animals. Especially high rates of human infection have been found in Bolivia, Peru, and Egypt, and this may be due to consumption of certain foods.<ref name="Mansons" /> No vaccine is available to protect people against ''Fasciola'' infection.<ref name=":1">{{Cite web |title= CDC - Fasciola - Prevention & Control |url= https://www.cdc.gov/parasites/fasciola/prevent.html |website= www.cdc.gov |access-date= 2015-07-17}}</ref> Preventative measures are primarily treating and immunization of the livestock, which are required to host the live cycle of the worms. Veterinary vaccines are in development, and their use is being considered by several countries on account of the risk to human health and economic losses resulting from livestock infection.<ref name="Mansons" /> Other methods include using [[molluscicide]]s to decrease the number of snails that act as vectors, but it is not practical.<ref name="Mansons" /> Educational methods to decrease consumption of wild watercress and other water plants have been shown to work in areas with a high disease burden.<ref name="Mansons" />

Fascioliasis occurs in Europe, Africa, the Americas as well as Oceania.<ref name="Mansons" /> Recently, worldwide losses in animal productivity due to fasciolosis were conservatively estimated at over US$3.2 billion per annum.<ref name="spithill99">{{cite book |last=Spithill |first=TW |author2= Smooker PM |author3= Copeman DB  |chapter= ''Fasciola gigantica'': epidemiology, control, immunology and molecular biology |editor=Dalton, JP |title= Fasciolosis |publisher=CABI Pub |location= Wallingford, Oxon, UK |year=1999 |pages=465–525 |isbn=0-85199-260-9 }}</ref> Fasciolosis is now recognized as an emerging human disease: the [[World Health Organization]] (WHO) has estimated that 2.4 million people are infected with ''Fasciola'', and a further 180 million are at risk of infection.<ref>Anonymus (1995). ''Control of Foodborne Trematode Infections''. ''WHO Technical Series No. 849''. WHO, Geneva, 157 pp.</ref>
{{TOC limit|3}}

==Signs and symptoms==
===Humans===
[[Image:F. hepatica adults in bile duct.jpg|300px|thumb|Adult flukes ''Fasciola hepatica'' in [[bile ducts]] (liver of goat)]] The course of fasciolosis in humans has 4 main phases:<ref name="Mas-Coma99"/>
* '''[[Incubation period|Incubation]] phase''': from the ingestion of metacercariae to the appearance of the first symptoms; period: few days to 3 months; depends on the number of ingested metacercariae and immune status of the host
* '''Invasive or acute phase''': fluke migration up to the bile ducts. This phase is a result of the mechanical destruction of the hepatic tissue and the [[peritoneum]] by migrating juvenile flukes causing localized and or generalized toxic and [[allergic]] reactions.<ref>Facey, R.V., Marsden, P.D. (1960). "Fascioliasis in man: an outbreak in Hampshire". ''Br. Med. J.'' ii, 619–625.
</ref> The major symptoms of this phase are:
** Fever: usually the first symptom of the disease; {{cvt|40|-|42|°C}}
** Abdominal pain
** Gastrointestinal disturbances: loss of appetite, [[flatulence]], [[nausea]], [[diarrhea]]
** [[Urticaria]]
** Respiratory symptoms (very rare): [[cough]], [[dyspnoea]], chest pain, [[hemoptysis]]
** [[Hepatomegaly]] and [[splenomegaly]]
** [[Ascites]]
** [[Anaemia]]
** [[Jaundice]]
* '''Latent phase''': This phase can last for months or years. The proportion of asymptomatic subjects in this phase is unknown. They are often discovered during family screening after a patient is diagnosed.<ref name="Mas-Coma99"/>
* '''Chronic or obstructive phase''':
This phase may develop months or years after the initial infection. Adult flukes in the bile ducts cause inflammation and hyperplasia of the epithelium. The resulting cholangitis and cholecystitis, combined with the large body of the flukes, are sufficient to cause mechanical obstruction of the biliary duct. In this phase, biliary [[colic]], [[epigastric]] pain, fatty food intolerance, nausea, jaundice, [[pruritus]], right upper quadrant abdominal tenderness, etc., are clinical manifestations indistinguishable from [[cholangitis]], [[cholecystitis]] and [[cholelithiasis]] of other origins. Hepatic enlargement may be associated with an enlarged [[spleen]] or ascites. In case of obstruction, the gall bladder is usually enlarged and [[edema]]tous with thickening of the wall (Ref: Hepatobiliary Fascioliasis:
Sonographic and CT Findings in 87 Patients During the InitialPhase and Long-Term Follow-Up. Adnan Kabaalioglu, Kagan Ceken, Emel Alimoglu, Rabin Saba, Metin Cubuk, Gokhan Arslan, Ali Apaydin. AJR 2007; 189:824–828). Fibrous adhesions of the gall bladder to adjacent organs are common. [[Lithiasis]] of the bile duct or gall bladder is frequent and the stones are usually small and multiple.<ref name="Mas-Coma99"/>

===Other animals===
Veterinary clinical<ref name="VetPract">{{cite web | last=Bardsley | first=Mike | title=Fasciolosis in cattle | website=[[Veterinary Practice (magazine)|Veterinary Practice]] | date=2021-10-05 | url=http://www.veterinary-practice.com/article/fasciolosis-in-cattle | access-date=2022-04-27}}</ref> signs of fasciolosis are always closely associated with infectious dose (amount of ingested metacercariae). In sheep, as the most common definitive host, the clinical presentation is divided into 4 types:<ref name=Dubinsky/><ref name=Behm99/>
* '''Acute Type I Fasciolosis''': infectious dose is more than 5000 ingested metacercariae. Sheep suddenly die without any previous clinical signs. [[Ascites]], [[abdomen|abdominal]] [[haemorrhage]], [[icterus (medicine)|icterus]], [[pallor]] of membranes, weakness may be observed in sheep.
* '''Acute Type II Fasciolosis''': infectious dose is 1000-5,000 ingested metacercariae. As above, sheep die but briefly show pallor, loss of condition, and [[ascites]].
* '''Subacute Fasciolosis''': infectious dose is 800-1000 ingested metacercariae. Sheep are [[lethargic]], anemic, and may die. Weight loss is a dominant feature.
* '''Chronic Fasciolosis''': infectious dose is 200-800 ingested metacercariae. The asymptomatic or gradual development of bottle jaw and ascites (ventral [[edema]]), emaciation, and weight loss.

In blood, [[anemia]], [[hypoalbuminemia]], and [[eosinophilia]] may be observed in all types of fasciolosis.<ref name=Behm99/> Elevation of [[liver enzyme]] activities, such as [[glutamate dehydrogenase]] (GLDH), [[gamma-glutamyl transferase]] (GGT), and [[lactate dehydrogenase]] (LDH), is detected in subacute or chronic fasciolosis from 12 to 15 weeks after ingestion of metacercariae.<ref>{{cite journal |author1=Anderson P.H. |author2=Matthews J.G. |author3=Berrett S. |author4=Brush P.J. |author5=Patterson D.S. | year = 1981 | title = Changes in plasma enzyme activities and other blood components in response to acute and chronic liver damage in cattle | journal = Res Vet Sci. | volume = 31 | issue = 1| pages = 1–4 |pmid=6118918 |doi=10.1016/S0034-5288(18)32510-4 }}</ref><ref>{{cite journal |author1=Sykes A.R. |author2=Coop A.R. |author3=Robinson M.G. | year = 1980 | title = Chronic subclinical ovine fascioliasis: plasma glutamate dehydrogenase, gamma glutamyl transpeptidase and aspartate aminotransferase activities and their significance as diagnostic aids. | journal = Res. Vet. Sci | volume = 28 | issue = 1| pages = 71–78 |doi=10.1016/S0034-5288(18)32775-9 |pmid=6103569 }}</ref> Economical effect of fasciolosis in sheep consists in sudden deaths of animals as well as in the reduction of weight gain and wool production.<ref>{{cite journal | last1 = Sinclair | first1 = K.B. | year = 1962 | title = Observations on the clinical pathology of ovine fascioliasis. | journal = Br. Vet. J. | volume = 118 | issue = 2| pages = 37–53 | doi = 10.1016/S0007-1935(17)43201-5 }}</ref><ref>{{cite journal | doi = 10.1111/j.1751-0813.1970.tb15573.x | last1 = Roseby | first1 = F.B. | year = 1970 | title = The effect of fasciolosis on the wool production of merino sheep | journal = Aust. Vet. J. | volume = 46 | issue = 8| pages = 361–365 | pmid = 5471269 }}</ref> In goats and cattle, the clinical manifestation is similar to sheep. However, acquired resistance to ''F. hepatica'' infection is well-known in adult cattle.<ref name=Haroun86>{{cite journal |vauthors=Haroun ET, Hillyer GV |title=Resistance to fascioliasis--a review |journal=Vet. Parasitol. |volume=20 |issue=1–3 |pages=63–93 |date=March 1986 |pmid=3518218 |doi= 10.1016/0304-4017(86)90093-2}}</ref><ref>{{cite journal | author = Doyle J.J. | year = 1973 | title = The relationship between the duration of a primary infection and the subsequent development of an acquired resistance to experimental infections with ''Fasciola hepatica'' in calves | journal =  Res. Vet. Sci | volume = 14 | issue = 1| pages = 97–103 | pmid = 4707901 | doi = 10.1016/S0034-5288(18)33945-6 }}</ref> Calves are susceptible to disease but more than 1000 metacercariae are usually required to cause clinical fasciolosis. In this case, the disease is similar to sheep and is characterized by weight loss, anemia, hypoalbuminemia, and (after infection with 10,000 metacercariae) death.<ref name=Boray69/> The Importance of cattle fasciolosis consists in economic losses caused by condemnation of livers at slaughter and production losses especially due to reduced weight gain.<ref>{{cite journal |vauthors=Phiri IK, Phiri AM, Harrison LJ |title=Serum antibody isotype responses of Fasciola-infected sheep and cattle to excretory and secretory products of Fasciola species |journal=Vet. Parasitol. |volume=141 |issue=3–4 |pages=234–42 |date=November 2006 |pmid=16797844 |doi=10.1016/j.vetpar.2006.05.019 }}</ref>

In sheep and sometimes cattle, the damaged liver tissue may become infected by the ''[[Clostridium]]'' bacteria [[Clostridium novyi|''C. novyi'']] type B. The bacteria will release toxins into the bloodstream resulting in what is known as [[black disease]]. There is no cure and death follows quickly. As ''C. novyi'' is common in the environment, black disease is found wherever populations of liver flukes and sheep overlap.<ref name=MERCK2>{{Cite web|url=https://www.merckvetmanual.com/|title=Merck Veterinary Manual|website=Merck Veterinary Manual}}</ref>

==Cause==
[[File:Fasciola LifeCycle 2013.png|thumb|350px|Immature eggs are discharged in the biliary ducts and in the stool <br />1. Eggs become embryonated in water 2, and eggs release miracidia 3, which invade a suitable snail intermediate host 4, including the genera Galba, Fossaria, and Pseudosuccinea. In the snail, the parasites undergo several developmental stages (sporocysts The number 4a, rediae The number 4b, and cercariae The number 4c). The cercariae are released from the snail 5 and encyst as metacercariae on aquatic vegetation or other surfaces. Mammals acquire the infection by eating vegetation containing metacercariae. Humans can become infected by ingesting metacercariae-containing freshwater plants, especially watercress 6. After ingestion, the metacercariae excyst in the duodenum 7 and migrate through the intestinal wall, the peritoneal cavity, and the liver parenchyma into the biliary ducts, where they develop into adults 8. In humans, maturation from metacercariae into adult flukes takes approximately 3 to 4 months. The adult flukes (Fasciola hepatica: up to 30 mm by 13 mm; F. gigantica: up to 75 mm) reside in the large biliary ducts of the mammalian host. Fasciola hepatica infects various animal species, mostly herbivores.<ref>{{Cite web|title = CDC - DPDx - Fascioliasis|url = https://www.cdc.gov/dpdx/fascioliasis/index.html|website = www.cdc.gov|access-date = 2015-07-16}}</ref>]]
Fasciolosis is caused by two [[Digenea|digenetic]] trematodes ''F. hepatica'' and ''F. gigantica''. Adult flukes of both species are localized in the [[bile duct]]s of the [[liver]] or [[gallbladder]]. ''F. hepatica'' measures 2 to 3&nbsp;cm and has a [[cosmopolitan distribution]]. ''F. gigantica'' measures 4 to 10&nbsp;cm in length and the distribution of the species is limited to the [[tropics]] and has been recorded in Africa, the Middle East, Eastern Europe, and South and Eastern Asia.<ref name="Torges99">{{cite book|title=Fasciolosis|last=Torgerson|first=P|author2=Claxton J|publisher=CABI Pub|year=1999|isbn=0-85199-260-9|editor=Dalton, JP|location=Wallingford, Oxon, UK|pages=113–49|chapter=Epidemiology and control}}</ref> In domestic livestock in Japan, [[diploid]] (2n = 20), [[triploid]] (3n = 30) and [[Chimera (genetics)|chimeric]] flukes (2n/3n) have been described, many of which reproduce [[parthenogenesis|parthenogenetically]]. As a result of this unclear classification, flukes in Japan are normally referred to as ''Fasciola'' spp.<ref>{{cite journal | last1 = Sakaguchi | first1 = Y. | year = 1980 | title = Karyotype and gametogenesis of the common liver fluke, ''Fasciola'' sp., in Japan. Jap | journal = J. Parasitol. | volume = 29 | pages = 507–513 }}</ref> Recent reports based on [[Mitochondrial DNA|mitochondrial genes]] analysis have shown that Japanese ''Fasciola'' spp. is more closely related to ''F. gigantica'' than to ''F. hepatica''.<ref>{{cite journal |vauthors=Itagaki T, Tsutsumi K |title=Triploid form of Fasciola in Japan: genetic relationships between Fasciola hepatica and Fasciola gigantica determined by ITS-2 sequence of nuclear rDNA |journal=Int. J. Parasitol. |volume=28 |issue=5 |pages=777–81 |date=May 1998 |pmid=9650058 |doi= 10.1016/S0020-7519(98)00037-X}}</ref> In India, a species called ''F. jacksoni'' was described in [[elephant]]s.<ref>{{cite journal | last1 = Singh | first1 = K.P. | last2 = Srivastava | first2 = V.K. | last3 = Prasad | first3 = A. | last4 = Pandey | first4 = A.P. | year = 1994 | title = Pathology due to ''Fasciola jacksoni'' in Indian elephants ''Elephas indicus'' | journal = Ind. J. Anim. Scien | volume = 64 | pages = 802–804 }}</ref>

===Transmission===
Human ''F. hepatica'' infection is determined by the presence of the intermediate snail hosts, domestic herbivorous animals, climatic conditions, and the dietary habits of man.<ref name=Chen/>  Sheep, goats and cattle are considered the predominant animal [[Natural reservoir|reservoir]]s. While other animals can be infected, they are usually not very important for human disease transmission. On the other hand, some authors have observed that [[donkey]]s and pigs contribute to disease transmission in Bolivia.<ref>{{cite journal | last1 = Mas-Coma | first1 = S. | last2 = Rodriguez | first2 = A. | last3 = Bargues | first3 = M.D. | last4 = Valero | first4 = M.A. | last5 = Coello | first5 = J. | last6 = Angles | first6 = R. | year = 1998 | title = Secondary reservoir role of domestic animals other than sheep and cattle in fascioliasis transmission on the northern Bolivian Altiplano | journal = Res. Rev. Parasitol | volume = 57 | pages = 39–46 }}</ref> Among wild animals, it has been demonstrated that the peridomestic [[rat]] (''Rattus rattus'') may play an important role in the spread as well as in the transmission of the parasite in [[Corsica]].<ref>{{cite journal | last1 = Mas-Coma | first1 = S. | last2 = Fons | first2 = R. | last3 = Feliu | first3 = C. | last4 = Bargues | first4 = M.D. | last5 = Valero | first5 = M.A. | last6 = Galán-Puchades | first6 = M.T. | year = 1988 | title = Small mammals as natural definitive hosts of the liver fluke, ''Fasciola hepatica'' Linnaeus, 1758 (Trematoda: Fasciolidae): a review and two new records of epidemiologic interest on the island of Corsica | journal = [[Rivista di Parassitologia]] | volume = 5 | pages = 73–78 }}</ref> In France, [[nutria]] (''Myocastor coypus'') was confirmed as a wild reservoir host of ''F. hepatica''.<ref>{{cite journal | doi = 10.1051/vetres:2001141 | last1 = Menard | first1 = A. | last2 = Agoulon | first2 = A. | last3 = L'Hostis | first3 = M. | last4 = Rondelaud | first4 = D. | last5 = Collard | first5 = S. | last6 = Chauvin | first6 = A. | year = 2001 | title = ''Myocastor coypus'' as a reservoir host of ''Fasciola hepatica'' in France | journal = Vet. Res. | volume = 32 | issue = 5| pages = 499–508 | pmid = 11592619 }}</ref>  Humans are infected by ingestion of aquatic plants that contain the infectious [[cercariae]].<ref>Markell, E.K., Voge, M., 1999. Medical Parasitology, eighth ed.. Saunders Company Publication, pp. 185–188.</ref> Several species of aquatic vegetables are known as a vehicle of human infection. In Europe, ''[[Nasturtium officinale]]'' (common watercress), ''[[Nasturtium sylvestre]]'', ''[[Rorippa amphibia]]'' (wild watercress), ''Taraxacum dens leonis'' ([[dandelion]] leaves), ''[[Valerianella olitoria]]'' (lamb's lettuce), and ''Mentha viridis'' ([[spearmint]]) were reported as a source of human infections.<ref name="Mas-Coma99"/> In the Northern Bolivian Altiplano, some authors suggested that several aquatic plants such as bero-bero (watercress), algas ([[algae]]), kjosco and tortora could act as a source of infection for humans.<ref>{{cite journal | last1 = Bjorland | first1 = J. | last2 = Bryan | first2 = R.T. | last3 = Strauss | first3 = W. | last4 = Hillyer | first4 = G.V. | last5 = McAuley | first5 = J.B. | year = 1995 | title = An outbreak of acute fascioliasis among Aymara Indians in the Bolivian Altiplano | journal = Clin. Infect. Dis. | volume = 21 | issue = 5| pages = 1228–1233 | pmid = 8589147 | doi=10.1093/clinids/21.5.1228}}</ref> Because ''F. hepatica'' [[cercaria]]e also encyst on water surface, humans can be infected by drinking of fresh untreated water containing cercariae.<ref name=Chen/> In addition, an experimental study suggested that humans consuming raw liver dishes from fresh livers infected with juvenile flukes could become infected.<ref>{{cite journal | doi = 10.1016/S0020-7519(97)00038-6 | last1 = Taira | first1 = N. | last2 = Yoshifuji | first2 = H. | last3 = Boray | first3 = J.C. | year = 1997 | title = Zoonotic potential of infection with ''Fasciola'' spp. by consumption of freshly prepared raw liver containing immature flukes | journal = Int. J. Parasitol. | volume = 27 | issue = 7| pages = 775–779 | pmid = 9279579 }}</ref>

===Intermediate hosts===
[[File:Galba truncatula.jpg|thumb|''[[Galba truncatula]]'' - the most common intermediate host of ''F. hepatica'' in Europe and South America]]

{{main|Fasciola hepatica#Life cycle|Fasciola gigantica#Intermediate hosts}}

Intermediate hosts of ''F. hepatica'' are freshwater snails from family [[Lymnaeidae]].<ref name=Torges99/><ref>{{cite book |last=Graczyk |first=TK |author2=Fried B |chapter=Development of ''Fasciola hepatica'' in the intermediate host.|editor=Dalton, JP |title=Fasciolosis |publisher=CABI Pub |location=Wallingford, Oxon, UK |year=1999 |pages=31–46 |isbn=0-85199-260-9 }}</ref> Snails from family [[Planorbidae]] act as an intermediate host of ''F. hepatica'' very occasionally.<ref name="Mas-Coma05"/>

==Mechanism==
The development of infection in a definitive host is divided into two phases: the parenchymal (migratory) phase and the biliary phase.<ref name=Dubinsky>Dubinský, P., 1993. Trematódy a trematodózy. In: Jurášek, V., Dubinský, P. a kolektív, Veterinárna parazitológia. Príroda a.s., Bratislava, 158–187. (in Slovakian)</ref> The parenchymal phase begins when excysted juvenile flukes penetrate the intestinal wall. After the penetration of the intestine, flukes migrate within the abdominal cavity and penetrate the liver or other organs. ''F. hepatica'' has a strong predilection for the tissues of the liver.<ref name=Behm99>Behm, C.A., Sangster, N.C., 1999. Pathology, pathophysiology, and clinical aspects. In: Dalton, J.P. (Ed.), Fasciolosis. CAB International Publishing, Wallingford, pp. 185–224.</ref> Occasionally, ectopic locations of flukes such as the lungs, [[Thoracic diaphragm|diaphragm]], intestinal wall, kidneys, and subcutaneous tissue can occur.<ref name=Boray69>{{cite journal |author=Boray JC |title=Experimental fascioliasis in Australia |journal=Adv. Parasitol. |volume=7 |pages=95–210 |year=1969 |pmid=4935272 |doi= 10.1016/S0065-308X(08)60435-2|series=Advances in Parasitology |isbn=978-0-12-031707-3}}</ref><ref name=Chen/> During the migration of flukes, tissues are mechanically destroyed and [[inflammation]] appears around migratory tracks of flukes. The second phase (the biliary phase) begins when parasites enter the [[biliary duct]]s of the liver. In biliary ducts, flukes mature, feed on blood, and produce eggs. [[Hypertrophy]] of biliary ducts associated with obstruction of the lumen occurs as a result of tissue damage.{{citation needed|date=May 2021}}

===Resistance to infection===
Mechanisms of resistance have been studied by several authors in different animal species. These studies may help to better understand the [[immune response]] to ''F. hepatica'' in the host and are necessary for the development of a vaccine against the parasite. It has been established that cattle acquire resistance to challenge infection with ''F. hepatica'' and ''F. gigantica'' when they have been sensitized with primary patent or drug-abbreviated infection.<ref name=Haroun86/> Resistance to fasciolosis was also documented in rats.<ref>{{cite journal |vauthors=van Milligen FJ, Cornelissen JB, Bokhout BA |title=Location of induction and expression of protective immunity against Fasciola hepatica at the gut level: a study using an ex vivo infection model with ligated gut segments |journal=J. Parasitol. |volume=84 |issue=4 |pages=771–7 |date=August 1998 |pmid=9714209 |doi= 10.2307/3284586|jstor=3284586 |publisher=The Journal of Parasitology, Vol. 84, No. 4}}</ref> On the other hand, sheep and goats are not resistant to re-infection with ''F. hepatica''.<ref>{{cite journal |vauthors=Chauvin A, Bouvet G, Boulard C |title=Humoral and cellular immune responses to Fasciola hepatica experimental primary and secondary infection in sheep |journal=Int. J. Parasitol. |volume=25 |issue=10 |pages=1227–41 |date=October 1995 |pmid=8557470 |doi= 10.1016/0020-7519(95)00039-5}}</ref><ref>{{cite journal |vauthors=Martínez-Moreno A, Martínez-Moreno FJ, Acosta I, Gutiérrez PN, Becerra C, Hernández S |title=Humoral and cellular immune responses to experimental Fasciola hepatica infections in goats |journal=Parasitol. Res. |volume=83 |issue=7 |pages=680–6 |year=1997 |pmid=9272558 |doi=10.1007/s004360050319 |s2cid=25375828 |url=http://link.springer.de/link/service/journals/00436/bibs/7083007/70830680.htm |url-status=dead |archive-url=https://web.archive.org/web/20010911180044/http://link.springer.de/link/service/journals/00436/bibs/7083007/70830680.htm |archive-date=2001-09-11 |url-access=subscription }}</ref> However, there is evidence that two sheep breeds, in particular [[Indonesian thin tail sheep]] and [[Red maasai sheep]], are resistant to ''F. gigantica''.<ref>{{cite journal |vauthors=Roberts JA, Estuningsih E, Wiedosari E, Spithill TW |title=Acquisition of resistance against Fasciola gigantica by Indonesian thin tail sheep |journal=Vet. Parasitol. |volume=73 |issue=3–4 |pages=215–24 |date=December 1997 |pmid=9477508 |doi= 10.1016/S0304-4017(97)00119-2}}</ref><ref>Wamae, L.W., 1996. Comparative pathogenesis and immunochemistry analysis of Fasciola gigantica infection in cattle and sheep. PhD Thesis. University of Edinburgh.</ref>

==Diagnosis==
Most immunodiagnostic tests will detect infection and have a sensitivity above 90% during all stages of the disease. In addition, antibody concentration quickly drops post-treatment and no antibodies are present one year after treatment, which makes it a very good diagnostic method.<ref name="Mansons" /> In humans, diagnosis of fasciolosis is usually achieved parasitologically by findings the fluke eggs in stool, and immunologically by [[ELISA]] and [[Western blot]]. Coprological examinations of stool alone are generally not adequate because infected humans have important clinical presentations long before eggs are found in the stools.{{citation needed|date=May 2021}}

Moreover, in many human infections, the fluke eggs are often not found in the faeces, even after multiple faecal examinations.<ref name="Chen" /><ref name="Hillyer88">{{cite book |last=Hillyer |first=GV |chapter=Fascioliasis and fasciolopsiasis.|editor=A. Turano |editor2=Balows, Albert |editor3=M. Ohashi |title=Laboratory diagnosis of infectious diseases: principles and practices |volume=1: Bacterial, mycotic, and parasitic diseases|publisher=Springer-Verlag |location=Berlin |year=1988 |pages=856–62 |isbn=0-387-96755-9 }}</ref> Furthermore, eggs of ''F. hepatica'', ''F. gigantica'' and ''Fasciolopsis buski'' are morphologically indistinguishable.<ref name="Hillyer88" /> Therefore, immunological methods such as ELISA and enzyme-linked immunoelectrotransfer blot, also called Western blot, are the most important methods in the diagnosis of ''F. hepatica'' infection. These immunological tests are based on the detection of species-specific [[antibody|antibodies]] from [[Blood plasma|sera]]. The [[antigen]]ic preparations used have been primarily derived from extracts of excretory/secretory products from adult [[worm]]s, or with partially purified fractions.<ref name="Hillyer99">{{cite book |last=Hillyer |first=GV |chapter=Immunodiagnosis of human and animal fasciolosis. |editor=Dalton JP |title=Fasciolosis |publisher=CABI Pub |location=Wallingford, Oxon, UK |year=1999 |pages=435–47 |isbn=0-85199-260-9 }}</ref> Recently, purified native and [[Recombinant DNA|recombinant]] antigens have been used, e.g. recombinant ''F. hepatica'' [[Cathepsin L1|cathepsin L]]-like [[protease]].<ref>{{cite journal |vauthors=O'Neill SM, Parkinson M, Strauss W, Angles R, Dalton JP |title=Immunodiagnosis of Fasciola hepatica infection (fascioliasis) in a human population in the Bolivian Altiplano using purified cathepsin L cysteine proteinase |journal=Am. J. Trop. Med. Hyg. |volume=58 |issue=4 |pages=417–23 |date=April 1998 |pmid=9574785 |doi= 10.4269/ajtmh.1998.58.417|url=http://www.ajtmh.org/cgi/pmidlookup?view=long&pmid=9574785|doi-access= |s2cid=23605813 |url-access=subscription }}</ref>

Methods based on antigen detection (circulating in serum or faeces) are less frequent. In addition, biochemical and haematological examinations of human sera support the exact diagnosis (eosinophilia, elevation of liver enzymes). [[Ultrasonography]] and [[Medical radiography|xray]] of the abdominal cavity, [[biopsy]] of the liver, and gallbladder punctuate can also be used (ref: US-guided gallbladder aspiration:
a new diagnostic method for biliary fascioliasis. A. Kabaalioglu, A. Apaydin, T. Sindel, E. Lüleci. Eur. Radiol. 9, 880±882 (1999) . False fasciolosis ([[pseudofasciolosis]]) refers to the presence of eggs in the stool resulting not from an actual infection but from recent ingestion of infected livers containing eggs. This situation (with its potential for misdiagnosis) can be avoided by having the patient follow a liver-free [[diet (nutrition)|diet]] several days before a repeat stool examination.<ref name="Hillyer99" />

In animals, intravital diagnosis is based predominantly on faeces examinations and immunological methods. However, clinical signs, biochemical and haematological profile, season, climate conditions, [[epidemiology]] situation, and examinations of snails must be considered.<ref name="Dubinsky" /><ref name="Torges99" /> Similarly to humans, faeces examinations are not reliable. Moreover, the fluke eggs are detectable in faeces 8–12 weeks post-infection. Despite that fact, faecal examination is still the only used diagnostic tool in some countries. While coprological diagnosis of fasciolosis is possible from 8- to 12 weeks post-infection (WPI), ''F. hepatica'' specific-antibodies are recognized using ELISA or Western blot after 2-4 weeks post-infection.<ref>{{cite journal |vauthors= Zimmerman GL, Jen LW, Cerro JE, Farnsworth KL, Wescott RB |title=Diagnosis of Fasciola hepatica infections in sheep by an enzyme-linked immunosorbent assay |journal=Am. J. Vet. Res. |volume=43 |issue=12 |pages=2097–100 |date=December 1982 |doi=10.2460/ajvr.1982.43.12.2097 |pmid=7165155 }}</ref><ref>{{cite journal |vauthors= Duménigo BE, Espino AM, Finlay CM, Mezo M |title= Kinetics of antibody-based antigen detection in serum and faeces of sheep experimentally infected with Fasciola hepatica |journal= Vet. Parasitol. |volume=89 |issue=1–2 |pages= 153–61 |date=March 2000 |pmid= 10729655 |doi= 10.1016/S0304-4017(00)00206-5 }}</ref> Therefore, these methods provide early detection of the infection.{{citation needed|date=May 2021}}

==Prevention==
In some areas, special control programs are in place or have been planned.<ref name=":1" /> The types of control measures depend on the setting (such as epidemiologic, ecologic, and cultural factors).<ref name=":1" /> Strict control of the growth and sale of watercress and other edible water plants is important. Individual people can protect themselves by not eating raw watercress and other water plants, especially from endemic grazing areas.<ref name=":1" /> Travelers to areas with poor sanitation should avoid food and water that might be contaminated (tainted).<ref name=":1" /> Vegetables grown in fields, that might have been irrigated with polluted water, should be thoroughly cooked, as should viscera from potentially infected animals.<ref name=":1" />

==Treatment==
===Humans===
Several drugs are effective for fascioliasis, both in humans and in domestic animals.  The drug of choice in the treatment of fasciolosis is [[triclabendazole]], a member of the [[benzimidazole]] family of [[anthelmintics]].<ref>{{cite journal |vauthors=Savioli L, Chitsulo L, Montresor A |title=New opportunities for the control of fascioliasis |journal=Bull. World Health Organ. |volume=77 |issue=4 |pages=300 |year=1999 |pmid=10327707 |pmc=2557651}}</ref> The drug works by preventing the polymerization of the molecule [[tubulin]] into the [[cytoskeleton|cytoskeletal structures]], [[microtubule]]s. Resistance of ''F. hepatica'' to triclabendazole has been recorded in Australia in 1995<ref>{{cite journal |author= Overend DJ & Bowen FL |year=1995 |title= Resistance of ''Fasciola hepatica'' to triclabendazole |journal= Australian Veterinary Journal |volume=72 |pages= 275–276 |doi= 10.1111/j.1751-0813.1995.tb03546.x |pmid= 8534235|issue=7}}</ref> and Ireland in 1998.<ref>{{cite journal |vauthors= Mulcahy G, Dalton JP |year=1998 |title= Vaccines in control of liver fluke infections in ruminants: current status and prospects |journal= Irish Vet J |volume=51 |pages= 520–525}}</ref>

[[Praziquantel]] treatment is ineffective.<ref>{{cite journal|vauthors= Schubert S, Phetsouvanh R | title = Praziquantel weitgehend unwirksam: Behandlung des ''Fasciola-hepatica''-Befalles (grosser Leberegel).| journal = Z Arztl Fortbild (Jena)| year = 1990| volume = 84| issue = 14| pages = 705–7| pmid = 2264356}}</ref><ref>{{cite journal|vauthors= Price TA, Tuazon CU, Simon GL | title = Fascioliasis: case reports and review.| journal = Clin Infect Dis| year = 1993| volume = 17| issue = 3| pages = 426–30| pmid = 8218685| doi=10.1093/clinids/17.3.426}}</ref> There are case reports of [[nitazoxanide]] being successfully used in human fasciolosis treatment in Mexico.<ref>{{cite journal |vauthors= Rossignol JF, Abaza H, Friedman H |title=Successful treatment of human fascioliasis with nitazoxanide |journal= Trans. R. Soc. Trop. Med. Hyg. |volume=92 |issue=1 |pages=103–4 |year=1998 |pmid= 9692168 |doi= 10.1016/S0035-9203(98)90974-9}}</ref> There are also reports of [[bithionol]] being used successfully.<ref>Ramachandran, A. (2000). ''Pharmacology Recall''.</ref>

[[Nitazoxanide]] has been found effective in trials, but is currently not recommended.<ref name="Mansons" />

===Domestic animals===
Only clorsulon and [[albendazole]] are approved for use in the treatment of domestic animals in the United States, but the available flukicides used worldwide also include [[triclabendazole]], [[netobimin]], closantel, [[rafoxanide]], nitroxynil, and [[oxyclozanide]]; however, this list of available drugs has some drawbacks.<ref name=":2">Ballweber, L. (2018). Fasciola hepatica in ruminants. Merck vet manual (1.2)</ref> Closantel, nitroxynil, and oxyclozanide are not effective against young liver flukes and should only be used to treat subacute and chronic infections. Triclabendazole is effective at killing flukes of any age, but over-use has resulted in increasing resistance to this drug, so it should only be used to treat early infections, with later stages treated with other fasciolicides.<ref>{{Cite web|url=https://www.nadis.org.uk/disease-a-z/sheep/liver-fluke-control-in-sheep/|title=NADIS Animal Health Skills - Liver Fluke Control in Sheep|website=www.nadis.org.uk|access-date=2019-09-07}}</ref> The timing of treatment is critical for success, and is determined by environmental factors and analysis of the expected distribution and prevalence of the disease. For example, in European countries that have large numbers of sheep, computerized systems predict when fascioliasis is most likely to make the biggest impact on sheep populations and how many sheep will most likely be affected. The predictions are dependent on guessing when environmental conditions that are most conducive to parasite multiplication will occur, such as the amount of rainfall, evapotranspiration, and the ratio of wet to dry days in a particular month. If heavy infections are expected to occur, treatment for sheep should begin in September/October, then again in January/February, and finally in April/May; the amount of hatching fluke eggs is minimal during these times because they require a warm, wet environment, making treatment more effective.<ref name=":2" />

==Epidemiology==
Human and animal fasciolosis occurs worldwide.<ref name=Torges99/> While animal fasciolosis is distributed in countries with high cattle and sheep production, human fasciolosis occurs, excepting Western Europe, in developing countries. Fasciolosis occurs only in areas where suitable conditions for intermediate hosts exist.{{citation needed|date=May 2021}}

Studies carried out in recent years have shown human fasciolosis to be an important [[public health]] problem.<ref name=Chen>Chen, M.G., Mott, K.E., 1990. "Progress in assessment of morbidity due to Fasciola hepatica infection: a review of recent literature". Trop. Dis. Bull. 87, R1–R38.</ref> Human fasciolosis has been reported by countries in Europe, America, Asia, Africa, and Oceania. The incidence of human cases has been increasing in 51 countries of the five continents.<ref name="Mas-Coma99"/><ref name="Esteb98"/> A global analysis shows that the expected correlation between animal and human fasciolosis only appears at a basic level. High prevalences in humans are not necessarily found in areas where fasciolosis is a great veterinary problem. For instance, in South America, [[hyperendemics]] and [[mesoendemics]] are found in Bolivia and Peru where the veterinary problem is less important, while in countries such as Uruguay, Argentina, and Chile, human fasciolosis is only sporadic or [[hypoendemic]].<ref name=Esteb98/>

===Europe===
In Europe, human fasciolosis occurs mainly in France, Spain, Portugal, and the former USSR.<ref name=Esteb98/> France is considered an important human endemic area. A total of 5863 cases of human fasciolosis were recorded from nine French hospitals from 1970 to 1982.<ref>Danis, M., Nozais, J.P., Chandenier, J., 1985. "La distomatose à ''Fasciola hepatica'', II: La fasciolose humaine en France". Action Vet. 907.</ref> Concerning the former Soviet Union, almost all reported cases were from the [[Tajikistan|Tajik Republic]].<ref name=Esteb98/> Several papers referred to human fasciolosis in Turkey.<ref>{{cite journal |vauthors=Yilmaz H, Gödekmerdan A |title=Human fasciolosis in Van Province, Turkey |journal=Acta Trop. |volume=92 |issue=2 |pages=161–2 |date=October 2004 |pmid=15350869 |doi=10.1016/j.actatropica.2004.04.009 }}</ref> Recently, [[serological survey]] of human fasciolosis was performed in some parts of Turkey. The prevalence of the disease was [[serology|serologically]] found to be 3.01% in [[Antalya Province]], and between 0.9 and 6.1% in [[Isparta Province]], Mediterranean region of Turkey.<ref>Demirci, M., 2003. Insanlarda epidemiyoloji. In: Tinar, R., Korkmaz, M. (Eds.), Fasciolosis. Türkiye Parazitoloji Derněgi, META Basim, İzmir, pp. 343–358 (in Turkish).</ref> In other European countries, fasciolosis is sporadic and the occurrence of the disease is usually combined with travelling to endemic areas.{{citation needed|date=May 2021}}

===Americas===
In North America, the disease is very sporadic. In Mexico, 53 cases have been reported. In Central America, fasciolosis is a human health problem in the Caribbean islands, especially in the zones of Cuba. [[Pinar del Río Province]] and [[Villa Clara Province]] are Cuban regions where fasciolosis was hyperendemic. In South America, human fasciolosis is a serious problem in Bolivia, Peru, and Ecuador. These [[Andes|Andean]] countries are considered to be the areas with the highest prevalence of human fasciolosis in the world. Well-known human hyperendemic areas are localized predominately in the high plain called [[altiplano]]. In the Northern Bolivian Altiplano, prevalences detected in some communities were up to 72% and 100% in [[coprology|coprological]] and [[serology|serological]] surveys, respectively.<ref name="Mas-Coma99"/> In Peru, ''F. hepatica'' in humans occurs throughout the country. The highest prevalences were reported in [[Arequipa]], [[Mantaro Valley]], [[Cajamarca]] Valley, and [[Puno Region]].<ref name="Mas-Coma05"/> In other South American countries like Argentina, Uruguay, Brazil, Venezuela and Colombia, human fasciolosis appear to be sporadic, despite the high prevalences of fasciolosis in cattle.{{citation needed|date=May 2021}}

===Africa===
In Africa, human cases of fasciolosis, except in northern parts, have not been frequently reported. The highest prevalence was recorded in Egypt where the disease is distributed in communities living in the [[Nile Delta]].<ref name="Mas-Coma05"/>

===Asia===
In Asia, the most human cases were reported in Iran, especially in [[Gīlān Province]], on the [[Caspian Sea]]. It was mentioned that more than 10,000 human cases were detected in Iran. In eastern Asia, human fasciolosis appears to be sporadic. Few cases were documented in Japan, Koreas, Vietnam, and Thailand.<ref name="Mas-Coma99"/>

===Australia and the Oceania===
In Australia, human fasciolosis is very rare (only 12 cases documented). In New Zealand, ''F. hepatica'' has never been detected in humans.<ref name="Mas-Coma99"/>

==Other animals==
[[Image:Triclabendazole.svg|thumb|Formula of triclabendazole]] Several drugs have been used to control fasciolosis in animals. Drugs differ in their efficacy, mode of action, price, and viability. Fasciolicides (drugs against Fasciola spp.) fall into five main chemical groups:<ref>{{cite journal |author=Fairweather I, Boray JC |title=Fasciolicides: efficacy, actions, resistance and its management |journal=Vet. J. |volume=158 |issue=2 |pages=81–112 |date=September 1999 |pmid=10489266 |doi=10.1053/tvjl.1999.0377 }}</ref>
* [[Halogenate]]d [[phenol]]s: bithionol (Bitin), hexachlorophene (Bilevon), nitroxynil (Trodax)
* [[Salicylanilides]]: closantel (Flukiver, Supaverm), rafoxanide (Flukanide, Ranizole)
* [[Benzimidazoles]]: triclabendazole (Fasinex), [[albendazole]] (Vermitan, Valbazen), mebendazol (Telmin), luxabendazole (Fluxacur)
* [[sulfonamide (medicine)|Sulphonamides]]: clorsulon (Ivomec Plus)
* [[Phenoxyalkane]]s: diamphenetide (Coriban)

Triclabendazole (Fasinex) is considered the most common drug due to its high efficacy against adult as well as juvenile flukes. Triclabendazole is used in the control of fasciolosis of livestock in many countries. Nevertheless, long-term veterinary use of triclabendazole has caused the appearance of resistance in ''F. hepatica''. In animals, triclabendazole resistance was first described in Australia,<ref>{{cite journal |vauthors=Overend DJ, Bowen FL |title=Resistance of Fasciola hepatica to triclabendazole |journal=Aust. Vet. J. |volume=72 |issue=7 |pages=275–6 |date=July 1995 |pmid=8534235 |doi= 10.1111/j.1751-0813.1995.tb03546.x}}</ref> later in Ireland<ref>O’Brien, D.J., 1998. Fasciolosis: a threat to livestock. Irish Vet. J. 51, 539–541.</ref> and [[Scotland]]<ref>{{cite journal |vauthors=Mitchell GB, Maris L, Bonniwell MA |title=Triclabendazole-resistant liver fluke in Scottish sheep |journal=Vet. Rec. |volume=143 |issue=14 |pages=399 |date=October 1998 |pmid=9802201 }}</ref> and more recently in the Netherlands.<ref>{{cite journal |vauthors=Moll L, Gaasenbeek CP, Vellema P, Borgsteede FH |title=Resistance of Fasciola hepatica against triclabendazole in cattle and sheep in The Netherlands |journal=Vet. Parasitol. |volume=91 |issue=1–2 |pages=153–8 |date=July 2000 |pmid=10889368 |doi= 10.1016/S0304-4017(00)00267-3}}</ref> Considering this fact, scientists have started to work on the development of new drug. Recently, a new fasciolicide was successfully tested in naturally and experimentally infected cattle in Mexico. This new drug is called 'Compound Alpha' and is chemically very similar to triclabendazole.<ref>{{cite journal |vauthors=Ibarra F, Vera Y, Quiroz H |title=Determination of the effective dose of an experimental fasciolicide in naturally and experimentally infected cattle |journal=Vet. Parasitol. |volume=120 |issue=1–2 |pages=65–74 |date=February 2004 |pmid=15019144 |doi=10.1016/j.vetpar.2003.12.005 |display-authors=etal}}</ref> Countries where fasciolosis in livestock was repeatedly reported:{{cn|date=June 2022}}
* Europe: UK, Ireland, France, Portugal, Spain, Switzerland, Italy, Netherlands, Germany, Poland
* Asia: Turkey, Russia, Thailand, Iraq, Iran, China, Vietnam, India, Nepal, Japan, Korea, Philippines
* Africa: Kenya, Zimbabwe, Nigeria, Egypt, Gambia, Morocco
* Australia and the Oceania: Australia, New Zealand
* Americas: United States, Mexico, Cuba, Peru, Chile, Uruguay, Argentina, Jamaica, Brazil

On September 8, 2007, Veterinary officials in [[South Cotabato]], Philippines said that laboratory tests on samples from cows, [[carabao]]s, and horses in the province's 10 towns and lone city showed the level of infection at 89.5%, a sudden increase of positive cases among large livestock due to the erratic weather condition in the area. They must be treated forthwith to prevent complications with [[surra]] and [[hemorrhagic]] [[septicemia]] diseases. Surra already affected all [[barangays]] of the [[Surallah]] town.<ref>{{Cite web|url=https://www.gmanetwork.com/news/topstories/regions/59646/sunstar-rise-in-animal-liver-fluke-cases-alarms-south-cotabato/story/|title=SunStar: Rise in animal liver fluke cases alarms South Cotabato|author=<!--staff writer-->|website=GMA News Online|date=8 September 2007 }}</ref>

== See also ==
* [[Fasciolopsiasis]]
* [[Clonorchiasis]]
* [[Fh8]] - chemical produced by fasciolosis infection in the liver

== References ==
{{Reflist}}

== External links ==
{{Medical resources
|  DiseasesDB      = 4757
|  ICD10           = {{ICD10|B|66|3|b|65}}
|  ICD9            = {{ICD9|121.3}}
|  ICDO            =
|  OMIM            =
|  MedlinePlus     =
|  eMedicineSubj   = ped
|  eMedicineTopic  = 760
|  MeshID          = D005211
}}
* [http://www.dpd.cdc.gov/dpdx/HTML/Fascioliasis.htm Fasciolosis Overview] {{Webarchive|url=https://web.archive.org/web/20080204054639/http://www.dpd.cdc.gov/dpdx/html/Fascioliasis.htm |date=2008-02-04 }} at [[Centers for Disease Control and Prevention|CDC]]
* [http://www.ajtmh.org/cgi/content/abstract/58/4/417?ck=nck Immunodiagnosis of fasciolosis in Bolivian Altiplano]
* [http://www.stanford.edu/class/humbio103/ParaSites2001/fascioliasis/Fasciola.htm#transmission Fasciolosis] {{Webarchive|url=https://web.archive.org/web/20090310023355/http://www.stanford.edu/class/humbio103/ParaSites2001/fascioliasis/Fasciola.htm#transmission |date=2009-03-10 }}
* [http://www.k-state.edu/parasitology/625tutorials/Hepatica.html Pictures of adult flukes]
* [http://www.k-state.edu/parasitology/625tutorials/Fasciola02.html Pictures of ''F. hepatica eggs'']

{{Consumer Food Safety}}
{{Helminthiases}}

[[Category:Helminthiases]]
[[Category:Veterinary helminthology]]
[[Category:Animal diseases]]
[[Category:Tropical diseases]]