Reported by Ocampo, Eirene Joy Louise N.

BSN110

‡ Parasites of the biliary duct, gall bladder and liver parenchyma (hepatocyte)

‡ They feed on blood

‡ Adult flukes produce eggs which are passed into the intestine

Juvenile flukes migrating through liver tissue:

Juvenile flukes gain entry into the host after the infectious metacercariae cysts are ingested on watercress or algae. The flukes can spend up to 8-12 weeks migrating through the liver tissue before it reaches the bile duct where it begins sexual reproduction.

Metacercaria - minute cases, usually round or spherical

- house intermediate stages of parasites

- ingested by the final stage host, allowing the

lifecycle to continue.

* Humans acquire Clonorchiasis also known as biliary trematodiasis by ingesting encysted metacercaria in undercooked or raw fish.

Fish with metacercariae

‡ Clonorchis sinensis (“Chinese liver fluke” or the “Oriental liver fluke”)

‡ Opisthorchis felineus (cat liver fluke)

‡ Opisthorchis viverini (Southeast Asian liver fluke)

‡ Fasciola hepatica (Sheep liver fluke)

‡ Fasciola gigantica (Giant liver fluke)

‡ Dicrocoelium dendriticum (Lancet liver fluke)

‡ Dicrocoelium hospes

‡ Metorchis albidus

‡ Metorchis conjunctus

‡ Protofasciola robusta

‡ Parafasciolopsis fasciomorphae

‡ Opisthorchis guayaquilensis

‡ Fasciola jacksoni

‡ Moderate-sized fluke at 1-2.5X0.3-0.5 cm

‡ Spindle-shaped, have broad midbodies and tapered ends

‡ The eggs have small comma-shaped processes at the abopercular end and measure 29X16 um.

(1) Embryonated eggs are discharged in the biliary ducts and in the stool .(2) Eggs are ingested by a suitable snail intermediate host ; there are more than 100 species of snails that can serve as intermediate hosts.  Each egg releases a 2a.miracidia , which go through several developmental stages (2b.sporocysts , 2c.rediae , and 2d.cercariae ).(3) The cercariae are released from the snail and after a short period of free-swimming time in water, they come in contact and penetrate the flesh of freshwater fish, where they encyst as metacercariae .

(4) Infection of humans occurs by ingestion of undercooked, salted, pickled, or smoked freshwater fish . (5) After ingestion, the metacercariae excyst in the duodenum and (6) ascend the biliary tract through the ampulla of Vater .  Maturation takes approximately 1 month.  The adult flukes (measuring 10 to 25 mm by 3 to 5 mm) reside in small and medium sized biliary ducts.  In addition to humans, carnivorous animals can serve as reservoir hosts.

‡ Causes the disease: Clonorchiasis

Epidemiology of CLONORCHIASIS:‡ Infection is through undercooked

freshwater fish with encysted metacercariae

‡ Widespread parasite of humans, dogs & cats. The last two are considered as important reservoirs

Epidemiology of CLONORCHIASIS:‡ Endemic in the Far East, especially in

Korea, Japan, Taiwan, and southern China, and infection occurs elsewhere among immigrants and those eating fish imported from endemic areas.

‡ It occurs in large areas of China

Symptoms of CLONORCHIASIS:

‡ General symptoms = fever = chills = epigastric pain = diarrhea = mild jaundice

Symptoms of CLONORCHIASIS:‡ In small quantities = asymptomatic

(Light infection)

‡ In large quantities = acute infection possibly lasting for less than 1 month

Acute phase irritation of bile ducts dilatation and

deviation liver become enlarged, necrotic, tender

impaired function

Symptoms of CLONORCHIASIS:‡ Modest infections = indigestion

= epigastric discomfort

= weakness

= loss of weight

‡ Heavier infections = anemia

= liver enlargement

= slight jaundice

= edema

= ascites

= diarrhea

Diagnosis of CLONORCHIASIS:‡ Occasionally by percutaneous transhepatic

cholangiography

‡ By indentifying eggs in the feces or duodenal contents by entero test (using a cotton thread fixed to a very light weight, both of which are enclosed in a capsule, except for the free end of the thread. The patient swallows the capsule and the end of the thread is held outside the mouth. After digestion of the capsule, the weight unrolls the encapsulated part of the thread and descends to the terminal part of the duodenum. The whole thread and weight are drawn back after about 3 hours, and all the material sticking to

the thread is collected by scraping)

Treatment and Control of CLONORCHIASIS:

‡ Administer 25 mg/kg (3x/day for 2 days) of Praziquantel – 100% cure rate

‡ Sometimes 10 mg/kg (1x/day for 7 days) of Albendazole is used

‡ Cook fish well ‡ Treat sewage before disposal

‡ Opisthorchis felineus = cat liver fluke

‡ Opishtorchis viverini = Southeast Asian liver fluke

‡ Life cycle similar to Clonorchis sinensis

‡ Adult forms are similar to Clonorchis sinensis but their eggs are slightly narrower (30 – 12 um)

‡ Eggs of O. viverini are relatively short and broad (ave.L = 26.7um;ave.breadth = 15um)

‡ Causes the disease: Opisthorchiasis ("Siberian liver fluke disease" or "cat liver fluke disease“)

Epidemiology of OPISTHORCHIASIS:‡ Opisthorchiasis is a parasitic disease that

can infect fish eating mammals, including humans.

‡ Human infection occurs through consumption of pickled, raw, or poorly cooked fish that contain the developing worms known as metacercariae.e.g. Koi-pla (uncooked freshwater fish dish)

Epidemiology of OPISTHORCHIASIS:‡ Commonly occurs in areas that eat raw or

pickled fish (East Prussia, Poland, Philippines, Korea, Japan and Vietnam)

‡ O. viverini is a major health problem in northern Thailand

‡ Prevalence: 85% = rural people 55% = urban people

Symptoms of OPISTHORCHIASIS:‡ Similar to C. sinensis since it inhabits

the bile ducts as well‡ Mild to moderate infection = general

malaise to abdominal

pain = upper right

quadrant or

epigastric pain ‡ Heavy & long standing =

cholangiocarcinoma (liver cancer)

Diagnosis of OPISTHORCHIASIS:

‡ Based on the symptoms present

‡ Based on the presence of an endemic infection in a given area

Treatment and Control of OPISTHORCHIASIS:

‡ Administer 25 mg/kg (3x/day for 1-2 days) of Praziquantel

‡ Praziquantel has no effect on cholangiocarcinoma.This indicates that infection must be entirely avoided to prevent a future diagnosis of cancer.

Treatment and Control of OPISTHORCHIASIS:

‡ Prevent fecal parasites from reaching the water supplies

‡ Decreasing snail hosts

‡ Promote adequate cooking methods for the second intermediate host fish

* Flukes causing Clonorchiasis and Orthorchiasis are differentiated by the shape of their testes, which are highly branched in Clonorchis and only lobed or slightly branched in Opisthorchis. The parasites also differ in their larval stage morphology, providing support for the retention of both Clonorchis and Opisthorchis genera.

‡ Fasciola hepatica = large (about 3 cm long, 1.5 cm wide)= “cephalic cone” at anterior end

‡ Fasciola gigantica = 7.4 cm length= have more attenuated body shape than the F. hepatica

‡ Eggs are operculated and measure 130 - 150 um in length and 63 – 90 um in breadth

(1) Immature eggs are discharged into the intestine and stool . (2) Eggs become embryonated in water , (3) eggs release miracidia , (4) which invade a suitable snail intermediate host . In the snail the parasites undergo several developmental stages (4a.sporocysts , 4b.rediae , and 4c.cercariae ). (5) The cercariae are released from the snail (6) and encyst as metacercariae on aquatic plants .(7) The mammalian hosts become infected by ingesting metacercariae on the aquatic plants.  After ingestion, the metacercariae excyst in the duodenum (8) and attach to the intestinal wall.  There they develop into adult flukes (20 to 75 mm by 8 to 20 mm) in approximately 3 months, attached to the intestinal wall of the mammalian hosts (humans and pigs).

The  adults have a life span of about one year.

‡ Causes the disease: Fascioliasis

Epidemiology of FASCIOLIASIS:‡ Humans become infected when they

eat watercress, water chestnuts, or other plants covered with the encysted metacercariae.

Metacercariae inflame and destroy tissue of liver

10 – 15 wks after flukes move to bile ducts

produce eggs

Epidemiology of FASCIOLIASIS:

‡ F. hepatica is common among herbivores and cosmopolitan distribution

‡ F. gigantica is a parasite of herbivores, particularly camels, cattle, and water buffalo in Africa and the Orient

Symptoms of FASCIOLIASIS:‡ Light infection = sign of biliary

obstruction= cholangitis= fever= chills= pain in the RUQ= jaundice= enlarged tender

liver= eosinophilia

Symptoms of FASCIOLIASIS:‡ Adult fluke attaches in pharyngeal

mucosa causing = pain = bleeding = edema (interferes with

respiration)* Halzoun (pharyngeal form of disease)

= common in the Middle East= from eating raw animal liver

Diagnosis of FASCIOLIASIS:

‡ By recovery of eggs using entero test

‡ By Ultrasonography in visualizing their presence

Treatment and Control of FASCIOLIASIS:

‡ Administer 30 - 50 mg/kg (every other day for 10 – 15 doses PO) of Bithionol

‡ Watercress should not be grown for human use in water in which herbivores have access

‡ WHO and Novartis Pharma AG have negotiated an agreement whereby Novartis will donate triclabendazole for the treatment of infected individuals in endemic countries (free of charge to such countries upon application from ministries of health)

‡ Also called the Lancet Liver Fluke

‡ 1 cm flukes found in the bile ducts

‡ Causes haepato-biliary damage – ending in cirrhosis – in sheep, hares and other herbivores

‡ Rarely in humans

‡ Has a typical life cycle with three different hosts, but, interestingly, it clearly alters the behavior of one of them, making it more likely to reach the next host (though this type of behavior control is suspected in many other parasites, it’s often not easy to prove)

The animal in which the adult flukes live is called the definitive host—the host in which the parasite multiplies sexually:

(1) Adult worms in the liver of the definitive host produce eggs that are washed out in the bile, mixed with the stool, and passed from the body.(2) Land snails feed on decaying animal droppings and ingest the eggs, whereupon the eggs hatch, releasing miracidia.(3) Miracidia migrate through the gut wall into the snail’s digestive gland, where they multiply asexually. Cercariae are produced. The snail is the first intermediate host for the fluke.(4) Cercariae exiting the snail’s tissues are encased in a coating of slime, which is left behind on the vegetation that the snail travels over. Transforming to metacercariaie, the parasites can be very numerous (hundreds in one slime ball) and are protected from drying out by the slime encasing them.

(5) Foraging ants collect the slime balls and carry them back to the nest, where the slime balls are eaten. Metacercariae encyst in the ant’s body cavity and become infective to the definitive host. One metacercaria travels to the ant’s nervous tissue and encysts there, an event which profoundly influences the ant’s behavior from then on - scientists are still unsure of how this works.(6) Infected ants crawl to the tops of blades of grass in the cool evenings and early mornings and cling there. This is the time when herbivores are grazing—the ant’s strange behavior makes the insect much more likely to be eaten by a grazing animal! In the heat of the day, when the dew dries up and animals rest in the shade, the ant that has not been eaten resumes its normal activities, only to ascend again when things cool down.(7) Metacercariae in ants that have been eaten migrate up the bile duct into the liver and mature to adult flukes in under two months. At about three months after infection, the worms begin producing eggs.

‡ Causes the disease: Dicrocoeliasis

Epidemiology of DICROCOELIASIS:‡ Unusual

‡ Many suspected cases are simply the result of the person having eaten the liver of an infected animal—typical eggs from flukes in the liver travel through the intestine and are passed in the stool without actual infection

Epidemiology of DICROCOELIASIS:

‡ True cases of human infection with the Lancet Fluke arise when people—accidentally or deliberately—eat ants

‡ Believed to be endemic or potentially endemic in 30 countries (throughout Europe = former U.S.S.R., Switzerland, Italy, Germany, Spain, Turkey ; the Middle East = Iran; Asia = China, Japan, Vietnam; Africa = Ghana, Nigeria, Sierra Leone; and in North and South America and Australia

Epidemiology of DICROCOELIASIS:

‡ Tends to be found in areas that favor the intermediate hosts, such as fields with dry, chalky and alkaline soils (main reservoirs are sheep, cows, land snails and ants)

‡ Can also been found in goats, pigs and even llamas and alpacas.

Symptoms of DICROCOELIASIS:‡ Infections of the biliary tree (mild) = biliary

colic = general digestive

disturbances (bloating and diarrhea)

‡ Heavier infections = enlarged bile ducts = enlarged biliary

epithelium = generation of fibrous tissue surrounding the ducts = hepatomegaly

= inflammation of the liver (cirrhosis)

Symptoms of DICROCOELIASIS:

‡ In one unique case, an infection with D. dendriticum was associated with acute urticaria.

Diagnosis of DICROCOELIASIS:

‡ Involves identification through eggs in the feces of a human or animal (not very accurate in humans)

‡ Examination of bile or duodenal fluid for eggs is a more accurate diagnostic technique

Treatment and Control of DICROCOELIASIS:

‡ Administer 25 mg/kg (3x/day for 1 day) of Praziquantel

‡ One German patient had 600mg of Praziquantel 3x/day for 3 days = also successful in eliminating the parasite from the body

‡ Treatment with triclobendazole‡ Administer 2 capsules of Mirazid (300mg)

for 6 days (effective in humans, sheep and goats)

Liver head magnified at 60x(the bar is 200 microns)

(A)Fasciola gigantica(B)Fasciola hepatica

Clonorchis sinensis acetabulum,genital pore