Fascioliasis( fasciola, liver fluke, giant fluke) - Causes, symptoms and treatment. MF.

Fascioliasis is a rather dangerous disease that affects agricultural animals and causes great harm to cattle-breeding farms( loss of livestock, loss of body weight, a significant reduction in milk yields and other).At the same time, it is a rather rare disease in a person, which is often found in the form of single or sporadic cases in almost all countries of the world. Parasitosis is periodically recorded in Central Asia, the Caucasus, Moldova, Belarus, France, Mexico, Peru, Chile, Cuba and many other countries.

Fascioliasis is a biohelminthosis caused by helminths of the genus Fasciola, mainly of chronic course, with liver and gall bladder damage.

The causes of fascioliasis

The causative agents of fascioliasis are two representatives of the type Plathelminthes( Flat worms), of the class Trematoda( Flukes), of the genus Fasciola. It is a hepatic fluke( Fasciola hepatica) and a giant fluke( Fasciola gigantea).The fasciolae have a flat body, various sizes: the dimensions of the hepatic fascia are about 20-30 mm with a width of 10 mm, and the giant one - 50-70 mm with a width of 10 mm. The body has a conical front part and a wider posterior part. The body has two suckers - oral and larger abdominal.

Sexually mature fasciolae

The internal organs of the parasite are branched. First there is a sucker, which includes the oral sucker, the preorrhoeic cavity and the pharynx. Then there is a short segment of the esophagus, which actually passes into two branchy loops of the intestine. In the middle part of the body of the fasciola testicles are located, which also branch. Nearby are the ovary, vitellaria and uterus. Eggs of fasciolae are oval in shape, and in F. gigantica they are more elongated, there is a yellowish-golden shell consisting of 2 layers. The size of eggs varies from 120 to 145 at 70-90 microns, and F. gigantica is larger.

The source of infection of are invasive animals. The final owner is herbivorous animals( cattle - cows, bulls, horses, small cattle - goats, sheep).Man is also the ultimate master. Parasitizes the helminth in the biliary tract of the final host for several years( up to 5 years or more).Intermediate host - freshwater mollusks( in particular, small pond snorkel).

The mechanism of infection of is alimentary, and the pathway is food or water. A person becomes infected by eating infected wild plants( sorrel, wild onion, cress - salad, vegetable greens), as well as raw water from inundated water bodies( ponds).Also, infection is possible when washing lettuce with pond water. With the use of fascioliasis of animals in the intestine, transient eggs enter that can not cause the disease, but can be found in the study of stool, so feces are examined repeatedly.

Fascioliasis, eggs F. hepatica

Susceptibility to fascioliasis is universal, people who visit freshwater reservoirs that gather grass near water bodies and eat it more often fall ill. Seasonality of the disease is summer.

Fasciola development cycle:

Helminth eggs are secreted by the final host of the parasite outward and must enter the water, where under favorable conditions( temperature from 22 to 29 ° C) develops further over about 18 days. Destructive for the development of the larva is the low temperature( 10 ° and below), and also the high temperature( 30 and above).At the end of 18 days, a larva( miracidia) appears from the egg, which freely floats in water. Then miracidia occurs in the body of the intermediate host - the small pond( Limnea truncatula), where a number of stages of development take place and in 30-70 days cercariae form( tailed larvae) that leave the mollusk.

Cercariae with suction cups attach to plants and are encysted( drop tail, covered with a dense shell that helps to survive).This stage is called adolescaria( invasive larva).Adolescaria perfectly preserved with humidity( up to a year), but faster die on drying( for several months).In the body of the final host fall with grass, water or, for example, hay. Thus, the larva enters the lumen of the intestine. Then, with blood flow( hematogenous), he gets to the liver and finds himself in the bile ducts, where he parasitizes. Also, larvae can reach another place - the lungs, the breast, the skin. After 1.5-2 months, the fasciola forms the hermaphroditic sexual system. Only after 3-3.5 months of parasitization, fasciolae lay eggs( the hermaphroditic reproductive system, but fertilization occurs in a cross way).During the parasitic period, a mature individual can postpone up to 2 million eggs.

Fascioliasis, life cycle

Pathogenic effect of fasciola on the human body

The fasciolae larvae pass through the blood( hematogenically) and in the tissue way: they actively penetrate the peritoneum, the glisson capsule( the fibrous capsule of the liver) and the liver parenchyma.

In the early phase of the disease, there is a toxic-allergic reaction of the body( allergic reactions);mechanical damage to the bile duct walls by parasite suckers( inflammation of the bile ducts);violation of the outflow of bile( stagnation);attachment of secondary microflora and, consequently, the occurrence of abscesses.

In the chronic phase, the development of destructive changes in liver tissue, the development of liver fibrosis with symptoms of portal hypertension( edema, fluid in the abdominal cavity, the risk of bleeding).

Immunity after disease is developed strong, type-specific.

Symptoms of fascioliasis

The incubation period ( the period from the moment of infection to the appearance of the first complaints) is 1-8 weeks after the invasion. Isolate acute or early phase of the disease and chronic phase.

The early stage of the disease is characterized by severe allergic manifestations( rash like urticaria), weakness, malaise, fever up to 39-40 ° C, headaches, epigastric pains( areas of the stomach), pain in the right upper quadrant( projection of the liver and gallbladder), nausea, vomiting, jaundice( first turn yellow eyes, then the mucous membrane of the mouth, upper and lower extremities, trunk), hepatomegaly( enlargement of the liver), its density during palpation( probing), soreness. Other toxic effects are possible, in particular, heart damage: increased heart rate( heart rate), unstable blood pressure increase, heart sounds during listening are muffled, rhythmic, the patient himself can complain of pain behind the sternum. Often the manifestations go by themselves. In the general analysis of blood - eosinophilia( up to 80%), leukocytosis( up to 20-50 * 109 / L), an increase in ESR.

The chronic phase of develops 1.5-2 months after infection. This phase of fascioliasis is characterized by the development of gastroduodenitis( nausea, decreased appetite, parodic pains in the abdomen of various types, unstable stools from mucous and watery to constipation), pain in the right hypochondrium of a paroxysmal nature, phenomena of cholestasis( yellowing of the mucous membranes and skin, pruritus) and functionalliver disorders. When examined, a dense, enlarged, painful liver is revealed. In biochemical blood tests: increase in the activity of blood enzymes - ALT, AST, APF, GGTP, it is possible to increase the total bilirubin both due to the indirect fraction and direct bilirubin, the protein spectrum disorders, albumin depletion, increase in gamma globulins gradually appear. In the general analysis of blood in the chronic phase, the increase in eosinophils is weak( up to 10%), unexpressed anemia.

Fascioliasis, fasciola in the liver

Complications of fascioliasis:

purulent angiocholangitis, liver abscess, mechanical jaundice, chronic cholecystitis, cirrhosis, possible lung damage, subcutaneous abscesses, lesion of the mammary glands.

Diagnosis of Fasciola

Diagnosis is made on the basis of:
1) Epidemiological data( the fact of bathing or eating water from inaccessible bodies of water, washing salad grasses with this water, using unwashed salad grasses for food).
2) Clinical data( symptoms of acute phase of the disease or chronic phase of parasitosis).
3) Laboratory diagnosis is performed depending on the stage of the disease. In the early phase - coprocopy is difficult, because eggs are produced in 3-3.5 months, so the main importance is acquired by serological methods of diagnosis, that is, the study of blood for the presence of antibodies - the reaction of the RNGA, ELISA.In the chronic phase - koprovoskopiya or duodenoscopy( detection of eggs fasciola in feces and duodenal contents).Investigation of feces( koprovoskopiya) is carried out twice in an interval of 7-10 days to exclude the detection of not true eggs, and transient( with the use of fascioliasis in canned food, pates).Prior to re-examination kalasubprodukty from the diet is excluded. Studies are carried out by the method of enrichment( because of the small number of eggs).

Differential diagnostics is performed with the following diseases: allergic
conditions and reactions, gastroduodenitis, hepatitis, cholecystitis, cholangitis, helminthiases of other etiology( opisthorchiasis, clonorchiasis, trichinosis), liver cirrhosis and others.

Treatment of fascioliasis

1) Organizational-regime measures: hospitalization is necessary in the early( acute) phase of fascioliasis. In the chronic phase, patients receive treatment on an outpatient basis.

2) In the early phase of the disease, antiparasitic treatment is prohibited in order to avoid deterioration of the patient's condition due to massive release of the products of vital functions of fasciolae when they are destroyed. In this phase, the patient's help is reduced to the appointment of pathogenetic and symptomatic therapy. Enzymes are prescribed( mezim, creon, mikrazim, enienzyme and others), hepatoprotectors and choleretic( carp, essliver, heptral, ursosan, ursofalk, hofitol, hepatrin, ovesol and others), antihistamines( zirtek, zodak, cetrin, claritin, erius, tavegil and others), drugs that affect intestinal motility( duspatalin, noshpa, buscopan and others), probiotics( bifidum, florin forte, biovestin, bifiform, linex, bion 3, yogulact and others), if necessary infusion detoxification therapy, antibioticsby indications and otherRupp preparations indicated.

3) Etiotropic antiparasitic therapy is prescribed only after the symptoms of the acute stage subsided. It is prescribed chloroxyl - 0.1-0.15 g / kg / day, biltricide - 75 mg / kg. Treatment is carried out under the strict supervision of the attending physician.

Control of treatment should be carried out at 3 and 6 months by examining faeces and duodenal contents.

Prevention of fascioliasis

Avoidance of infection with such parasitosis as fascioliasis is necessary to comply with a number of rules:
- Eliminate the use of unboiled water from inactive reservoirs. If it is impossible to boil and the absence of other drinking sources - filter this water through the tissue.
- Thoroughly wash all salad grasses with water followed by peeling with boiling water or blanch before consuming in boiling water for a few minutes.
- Prevention also reduces to sanitary and veterinary measures( prophylactic deworming of livestock, use for feed of hay cattle no earlier than 6 months after harvesting, changing pastures), fighting molluscs in water bodies. Also, preventive measures include the timely detection and deworming of patients with fascioliasis.

The doctor infektsionist Bykova N.I.