Wide tapeworm (diphyllobothriasis)
Diphyllobothriasis is a chronic parasitic infection caused by a broad tapeworm. This helminth belongs to the tape parasites. The main route of human invasion is the consumption of contaminated fish. The widespread prevalence of this type of helminthiasis in the population of fish living in regions with a temperate climate makes the consumption of this product with concern. This disease is diagnosed in Canada and North America, Germany, France, Italy, Holland, Finland and other European countries. In Russia, diphyllobothriasis occurs in the basins of the Siberian rivers - Yenisei, Amur, Lena, Ob, as well as in the lakes and rivers of Tatarstan, Samara, Nizhny Novgorod, Volgograd.
Content:
- Who is the broad tapeworm?
- Diphyllobothriasis symptoms
- Consequences of diphyllobothriasis for human health
- Ways of infection with a broad tapeworm
- Treatment of diphyllobothriasis
- Prognosis for the development of diphyllobothriasis
- Prevention of invasion by a wide tapeworm
Who is the broad tapeworm?
Diphyllobothrium latum is a tapeworm that ranges from 2 to 10 meters in length. Some specimens exceed this length. The broad tapeworm belongs to the class of cestodes (Cestoda), the family Diphyllobothriidae. It consists of a neck, on which there is a scolex (head) with two slit-like devices for attaching the helminth to the mucous membrane of the small intestine, and the body.
The body of the tapeworm consists of a huge number of segments, their number reaches 4 thousand. Large oval eggs are formed in mature segments. They are protected by a two-layer sheath and have a cover at one of the poles. Being in the intestines of the intermediate or final host, the tapeworm releases immature eggs that reach full maturity only in fresh water of reservoirs.
Diphyllobothriasis symptoms
From the moment the tapeworm is introduced into the human body until the first significant symptoms appear, it can take from 20 to 60 days. The manifestations of the disease develop gradually, they may be mild for a long time.
Infection symptoms:
- Nausea, vomiting;
- Cramping abdominal pain;
- Increased salivation (hypersalivation);
- Fatigue;
- A slight increase in temperature to subfebrile values;
- Decreased or increased appetite, weight loss;
- Alternating constipation and diarrhea;
- The appearance in the feces of body fragments of a tapeworm in the form of scraps of whitish ribbons;
- Intestinal obstruction with the accumulation of worms in the lumen of the small intestine;
- Signs of anemia with vitamin B12 deficiency (weakness, tachycardia, dizziness, pallor of the skin, swelling of the face, hands and feet, cracked tongue, atrophy of the taste buds, damage to the oral mucosa);
- Damage to the nervous system (numbness of the limbs, impaired sensitivity, wobbly gait);
- Violations of the blood composition (a decrease in the number of leukocytes, erythrocytes, platelets, hemoglobin of blood, an increase in the color index, the appearance of megaloblasts, megalocytes).
The intensity of the symptoms depends on the degree of damage to the body, concomitant pathologies, and diet. In severe cases, hepatomegaly, enlarged spleen, extremely low secretion of gastric juice are noted. The accumulation of many individuals of helminths in the intestinal lumen leads to obstructive intestinal obstruction. There are cases of latent (latent) infection.
Consequences of diphyllobothriasis for human health
The consequences of the stay of the helminth in the human gastrointestinal tract:
- Tissue necrosis and atrophic processes develop at the site of attachment of the scolex scolex to the intestinal mucosa;
- Disorders of the gastrointestinal tract occur due to damage to the nerve endings of the mucous membrane and disorders of intestinal trophism;
- The waste products of the broad tapeworm sensitize the body, causing allergic reactions;
- Megaloblastic anemia appears due to the fact that vitamins B1, B6, B12 are adsorbed by the parasite.
A severe form of anemia leads to neurological disorders: depression, increased irritability, hyperreflexia, paresthesia.
Ways of infection with a broad tapeworm
Infection with a broad tapeworm occurs in an alimentary way. The parasite infestation occurs during the consumption of infected fish or eggs, which can be either slightly salted or insufficiently thermally processed. In the muscles or in the internal organs of such fish (chum salmon, pink salmon, pike perch, burbot, ruff, pike) there is a plerocercoid - an intermediate form of development of a wide tapeworm.
It is most likely that such caviar or fish was salted at home in violation of the proportions or salting technology. Sometimes infection occurs through contaminated dishes, knives, cutting boards. Those who prefer to eat raw fish or caviar and cook fish kebab are at great risk.
The development cycle of the parasite:
- From the small intestine of an infected person or animal, the eggs of the broad tapeworm fall into the external environment.
- In some of the eggs that have fallen into the water, the embryo of the tapeworm develops. If the water temperature does not drop below + 15 ° C, the embryo (coracidia) goes into open water after 1-2 weeks.
- At a temperature not higher than + 20 ° C, it remains viable in fresh water for up to six months.
- In the body of a freshwater crustacean that has swallowed the embryo, it turns into a larva (procercoid).
- Predatory fish or fish of the chum family swallow crustaceans together with procercoids.
- In the body of fish, the larvae penetrate the intestinal wall into the muscles and continue their development, transforming within a month into a plerocercoid ranging in size from 1 to 5 cm together with bothria. This form of development of the tapeworm can be seen with the naked eye.
- The plerocercoid, together with the fish, enters the body of the final host (human) and continues its development in the small intestine.
- After 2-4 weeks, the larva turns into a sexually mature individual and begins a new development cycle.
From the egg stage to the appearance of a sexually mature individual, 6-7 months pass under favorable circumstances. In the human body, the broad tapeworm can parasitize up to 20 years. A sexually mature female broad tapeworm is able to produce up to 2 million eggs per day.
In addition to humans, the ultimate host of this parasite can be cats, dogs, pigs, foxes and bears. Although they intensively excrete parasite eggs along with feces, they are not directly dangerous to others, since the embryos have not gone through the development path to an invasive state.
Treatment of diphyllobothriasis
Before treating diphyllobothriasis, the doctor diagnoses helminthiasis. Anamnesis of epidemiological manifestations is preliminarily collected. It includes such items as living near a fresh water body, fishing, eating independently caught and salted fish.
Laboratory research:
- Analysis of feces for the detection of tapeworm eggs and parts of its body;
- A blood test to determine signs of hyperchromic anemia;
- Complete blood count to detect neuropenia and thrombocytopenia;
- Biochemical blood test for the content of haptoglobin and lactate hydrogenase.
After analyzing all the indicators, the helminthologist recommends effective drugs for the treatment of diphyllobothriasis. At the preparatory stage, the therapy of vitamin deficiency and iron deficiency anemia is carried out. Within a month, the patient takes iron preparations, injections of vitamin B 12.
Antihelminthic drugs:
- Praziquantel - leads to paralysis of the muscles of the parasite, is used to treat children from 4 years old, side effect is a decrease in concentration.
- Biltricide is contraindicated in pregnant women, the drug dose is 60-75 mg / kg body weight, the daily dose is divided into 3 doses.
- Niclosamide is used to treat children from 2 years of age (0.5 g / day), the therapeutic dose for adults and adolescents from 14 years of age is 2-3 g / day, accompanied by the use of laxatives.
To reduce the intensity of toxic poisoning and allergies, the intake of these drugs is accompanied by antihistamines - Tavegil, Suprastin, Cetrin, Diazolin.
Prognosis for the development of diphyllobothriasis
With careful implementation of the doctor's recommendation, the prognosis of recovery is optimistic. After the antiparasitic therapy, unstable immunity develops, re-infection with diphyllobothriasis is not excluded.
Prevention of invasion by a wide tapeworm
To protect yourself from infection with a wide latte, you need to carefully monitor the full-fledged culinary processing of fish: fry it for at least 30-40 minutes, salt it for 10 days, freeze fish products to destroy the larvae of parasites.
Fishermen and workers in the processing industry should undergo professional examinations in a timely manner, especially during the greatest activity of the parasite larvae. When the first symptoms of the disease appear, you should immediately undergo an in-depth examination by a parasitologist.
Author of the article: Danilova Tatyana Vyacheslavovna | Infectionist
Education: in 2008 received a diploma in General Medicine (General Medicine) at the Pirogov Russian Research Medical University. Immediately passed an internship and received a diploma of a therapist
