Diphyllobothriasis( wide ribbon) - Causes, symptoms and treatment. MF.

One of the dangerous parasites, capable of infecting humans and transmitting through the fish, is a wide ribbon. Its fairly wide prevalence among the fish pools of many rivers in the world causes a certain alarm and alertness, and the disease itself requires careful consideration.

Diphyllobothriasis is an intestinal helminthiasis of a chronic course caused by a ribbon parasite - a wide ribbon, and characterized by the defeat of the small intestine and the development of B12 - deficiency anemia.

Source of infection with diphyllobothriasis for humans

The relationship between the frequency of prevalence of diphyllobothriasis and the basins of many rivers of the planet, the location of lakes, as well as with moderate and cold climates has been noted. The disease is widespread in North America, Canada, France, Denmark, Sweden, Holland, Finland, Italy, Germany and other countries. In the Russian Federation, diphyllobothriasis is more common in the Krasnoyarsk Territory, in the basins of the rivers Ob, Lena, Yenisei, and Amur. Foci in the reservoirs of Nizhny Novgorod, Volgograd, Samara, Tatarstan have been identified.

Causes of development of diphyllobothriasis

The causative agent of the disease is Diphyllobothrium latum( ribbon broad), a tapeworm with a length of 2 to 10 meters or more. Refers to the class Cestoda, the family Diphyllobothriidae. It consists of a head( scolex), which has two slit-shaped botryas for attachment to the intestinal mucosa, neck and body, consisting of segments in which eggs are formed. The length of the body is determined by the huge number of segments - up to 4000 pieces, and the eggs are allocated only by the mature segments. Eggs of the parasite are oval in shape, sufficiently large by the standards of helminth eggs and are up to 70 microns, surrounded by a 2-layered shell, and also equipped with a single-pole lid. Parasitizing in the intestine, the lentian only allocates immature eggs, their further development occurs in the environment( in freshwater reservoirs).

Diphyllobothriasis, adult individual lente wide

The cycle of development of a wide ribbon occurs with the change of 3 hosts:
- the final host - a man, a cat, a dog, a pig, a bear, a fox;
- intermediate host - Cyclops crustaceans;
- additional hosts - freshwater fish.

Infection with occurs when eating less thermally processed fish.

Parasitizes the helminth in the small intestine. With faeces the eggs of the tapeworm fall into the external environment, into the water. First, an embryo is formed inside the egg, which then, under favorable conditions( temperature plus 15 °), leaves the water body after 6-16 days. The embryo actively swims in the water, remaining viable up to 6 months. It is fatal to the embryo to have a temperature above plus 20 °, salty water. After ingestion of freshwater crayfish in 2-3 weeks the embryo turns into procercoid( invasive larvae).Crustaceans with procercoids are swallowed by predatory fish( ruff, perch, pike perch, pike, burbot) or by salmonids( pink salmon, chum) in which they migrate to the musculature and other organs, where within 4-5 weeks they transformin the plerocercoid( about 1-3-5 cm long with the botryas).

The plerocercoid is an invasive stage for humans. Already in the body of the final host, they become a mature parasite( the plerocercoids attach to the mucosa of the small intestine and after 15-30 days reach the adult stage).

The whole cycle lasts an average of 25 weeks. Life expectancy of the parasite is 20 years or more.

Diphyllobothriasis, life cycle of

Thus, the source of infection in diphyllobothriasis is the final host( man, domestic animals - cat and dog, pig, fox, bear), in the body of which a mature adult of a wide ribbon can parasitize and egg fecesup to 2 million eggs per day or more) into the environment. However, it must be remembered that for the invasion of eggs must go a certain path of development to the invasive stage, so the final host is not directly contagious for others.

Diphyllobothriasis, broad-taped egg

The infection mechanism is alimentary. Invasion occurs as a result of eating insufficiently thermally processed or raw fish( ruff, perch, pike perch, pike, burbot, pink salmon, chum), in the organism of which the plerocercoid is located - a stage of parasite development that is contagious for humans. The plerocercoid can be found both in internal organs and in the muscle tissue of fish. Many of the patients used salted fish and slightly salted caviar, cooked at home. In rare cases, infection occurs through transmission factors( cutting board and knives, dishes contaminated with plerocercoids).Often ill lovers of raw food( fish, caviar), cooking shish kebabs from fish.

Susceptibility to diphyllobothriasis is universal. The adult population is more likely than in childhood.

Pathogenic action of a wide ribbon on the human body

1) mechanical action of helminths on the intestinal wall at the site of their attachment( with the development of necrosis and atrophy of tissues);
2) irritation of the nerve endings of the mucous membrane with the development of neuro-trophic disorders, which leads to disruption of the functions of the gastrointestinal tract;
3) allergic reactions due to the sensitization of the body with the products of the vital activity of the parasite;
4) hypo- and avitaminosis B12 and folic acid, and as a result - megaloblastic anemia( disruption of gastromucoprotein-internal gastric factor binding to vitamin B12, as a result of which the vitamin is not absorbed but adsorbed by the ribbon).Also, the level of vitamins C, B1, B6 in the blood of patients may decrease.
Immunity after the transferred helminthiosis is unstable, repeated invasions are possible.

Symptoms of diphyllobothriasis

The incubation period( from the moment of infection to the appearance of patient complaints) can last from 20 to 60 days. Most manifestations of the disease are mild. The onset of the disease is gradual.

First, there is nausea, sometimes vomiting, pain throughout the abdomen, mild fever, unstable stool, changes in appetite( increased or decreased).Some patients may develop intestinal obstruction associated with the accumulation of the ribbon in the small intestine.

Characteristic of the development of B12-deficiency anemia, manifested by weakness, dizziness, palpitation, fatigue, pale skin, swelling on the face or extremities, glossitis may develop( bright red spots, cracks, and then atrophy of the papillae, the tongue becomes "varnished").Such changes can be on the gums, mucous membranes of the cheeks, pharynx, esophagus( pain when eating).

There may be lesions of the nervous system( numbness, paresthesia - "crawling sensation", violation of superficial and deep sensitivity, unstable gait).There may be manifestations of funicular myelosis( as in the case of pernicious anemia of Addison-Burmer) - the patient has unexpressed paresthesia, impaired sensibility.

Changes in the general blood test: decrease in the number of red blood cells, hemoglobin, but the color index is increased. There may be Jolly's bodies( blood elements with the remains of nuclei) and Keboat rings( with basophilic punctuation polychromatophiles), megaloblasts, megalocytes. Also noted is leukopenia( a decrease in white blood cells), thrombocytopenia( a decrease in platelets).

The severity of anemia depends on the degree of invasion, the presence of concomitant diseases, the quality of nutrition of patients.

Sometimes the disease occurs latently( secretly, without clinical symptoms).

Diagnosis of diphyllobothriasis

Diagnosis is based on clinical and epidemiological data, as well as results of laboratory studies.

1) epidemiological history( stay in the endemic area, the fact that 20-60 days ago, raw, lightly salted, insufficiently thermally processed fish and its products, for example, caviar);
2) clinical data( the appearance of one or more groups of symptoms of varying severity), sometimes patients complain of the separation of stool with a bowel movement of parts of the stellite( body) of the broad ribbon;

Diphyllobothriasis, segments or segments

3) paraclinic data: general blood analysis( reduction of the number of red blood cells and hemoglobin at normal or increased color index, appearance of altered blood cells - Jolly's body( blood elements with nuclear remains) and Kebota rings( with basophilic punctuation polychromatophiles), the appearance of megaloblastscells, a decrease in the number of leukocytes and platelets).
4) Specific parasitological studies: coprocopy( detection of fragments of the body of the parasite( joints) with microscopy).

Differential diagnosis is carried out with anemia of various genesis( hemolytic, iron deficiency, hyperchromic), as well as other parasitological diseases( trichocephalosis, ankylostomiasis).

Treatment of diphyllobothriasis

Treatment is based on the use of antiparasitic agents. For treatment are used:
- Fenasal( niklosamid) once from 1 to 3 grams, depending on the age of the patient.
- Bildricide in an average dose of 25 mg / kg once.
- Extract of the seeds of the male fern : for 2 days a light diet, devoid of fats, spicy food, on the eve of therapy in the evening a light supper, at night saline laxative( magnesium sulphate), in the morning on an empty stomach put a cleansing enema, then taking the drug 1 capsule each2 minutes( total dose, depending on the age of 4 to 7 grams).After 30 minutes, again give a salt laxative, after 1.5 hours - a light breakfast. If there is no stool for 3 hours, then a cleansing enema is made.
- Pumpkin seeds in the amount of 300 grams, pour 50-60 ml of warm water, rub and eat on an empty stomach for 1 hour. After 3 hours, give a salt laxative and then after 30 minutes - a cleansing enema. You can seed the seeds in a water bath( as in the case of a shadow).

With severe anemia, it is corrected: it is prescribed vitamin B12 or cyanocobalamin from 200 to 500 μg parenterally 3 times a week for 1-1.5 months, as well as iron preparations( ferroplex, activiferin, ferronal, haemophores and others).

Symptomatic therapy( painkillers, probiotics, drugs normalizing intestinal motility, if necessary laxatives and others).

The prognosis of the disease is favorable.

The control of treatment is carried out 1 and 3 months after the antiparasitic therapy. With negative analyzes of coproonoscopy in the future, clinical examination is not required. If the departure of eggs and fragments of the stapillae of the Ribeteller continues, then a second course of treatment is prescribed.

Prevention of diphyllobothriasis

When catching and using river and lake fish, do not allow it to be raw, carefully monitor its thermal processing. The plerocercoids are quite stable. Bend at minus 15 ° during the day( 24 hours), at minus 10 ° during 3 days, at minus 4-6 ° for 9-10 days. High temperatures are more pernicious for plerocercoids - they die at a temperature of plus 55-60 °, in other words: it is recommended to roast fish for at least 20 minutes, and large pieces of fish - at least 30-40 minutes. Salt products are allowed to be consumed with a salt content in the final product of at least 9%, in which case the plerocercoids are killed.

Diphyllobothriasis, plerocercoids in fish meat

Timely detection of symptoms and treatment of diphyllobothriasis. Regular inspection for helminthosis of fishermen before and after navigation, workers of fish processing enterprises.

The doctor infektsionist Bykova N.I.