Teniarynchosis is a parasitic disease from the group of biohelminthiasis, manifested by symptoms of damage to the digestive tract and toxic-allergic reactions. With teniarynchosis, nausea, abdominal pain, unstable stools, a sharp increase in appetite and weight loss, independent crawling of parasite segments through the anus, asthenovegetative and neurotic syndromes, urticaria are observed. The diagnosis of teniarynchosis is based on the data of anamnesis, coproovoscopy, perianal-rectal scraping, radiography of the small intestine. Treatment of teniarynchosis consists in taking anthelmintic drugs (niclosamide, praziquantel).
Teniarynchosis is a chronic protozoism caused by tapeworm – bovine tapeworm, accompanied by intoxication and dyspeptic disorders. Teniarynchosis is common on all continents, but an increased incidence rate is characteristic of territories with developed cattle breeding – Central and Southern Africa, South America, Australia, the Eastern Mediterranean, Southeast and Central Asia, as well as Mongolia and China. Teniarynchosis has a focal prevalence, as a rule, in rural areas. Most often, helminthiasis infects the population that eats fresh or insufficiently heat-treated beef meat. The peak of teniarinhoz infections is noted during the period of mass slaughter of livestock (usually in autumn and winter). Female persons suffer from teniarynchosis less often than men; children – less often than adults.
Teniarynchosis develops when a person is infected with a bovine tapeworm – Taeniarhynchus saginatus, which is a tapeworm up to 4-6 m long, sometimes up to 10-12 m. The body (strobila) of the helminth has a head (scolex) with four well-developed suckers and 1-2 thousand segments (proglottids). Each segment contains up to 150 thousand rounded eggs containing an already formed larva (oncosphere), which does not require maturation in the external environment.
The development cycle of the bovine chain includes the change of two owners: the intermediate one – cattle and the main one – man. Adult individuals of bovine tapeworm for a long time (up to 20 years) parasitize in the human small intestine, which serves as a source of infection of the environment with eggs with oncospheres. The greatest danger is posed by workers caring for animals (milkmaids, calves, animal technicians, shepherds). The terminal segments of the helminth come off and actively crawl out through the anus or passively stand out with feces. This leads to mass seeding of pastures, places where livestock and forage are kept. Helminth eggs are sensitive to the action of solutions of bleach and carbolic acid (they die after a few hours), but they remain in external conditions for up to 1 month.
With contaminated feed, the eggs of the tapeworm enter the digestive tract of cows, penetrate into the muscle tissue, where they turn into invasive larvae – finns or cysticerci containing protoscolex of mature tapeworm. The viability of the finn in the muscles is maintained for 1-3 years. Infection of a person with teniarinchosis occurs in an alimentary way when eating insufficiently heat-treated or salted finnose beef. Under the action of gastric juice and bile, protoscolex leaves the wound, is fixed by suction cups to the intestinal wall, giving rise to the growth of the parasite. For 2.5-3 months of strobilation, an adult helminth develops. Usually, with teniarynchosis, a single individual of bovine tapeworm parasitizes in the human intestine.
Teniarynchosis manifests itself after the full development of the helminth and can have a different clinical course – from low-symptomatic to severe, pronounced. Often, the only sign of invasion is the detection of bovine tapeworm segments in the feces or their independent crawling out through the anus, accompanied by unpleasant sensations and the development of neurotic disorders in the patient.
Suckers and movable segments of bovine tapeworm have a traumatic effect on the mucous membrane of the small intestine, cause irritation of mechanoreceptors, impaired motility and secretion of the gastrointestinal tract, the development of catarrhal inflammation. Patients with teniarynchosis feel a feeling of heaviness in the epigastrium, heartburn, increased salivation, nausea, vomiting, abdominal pain of unclear localization, flatulence, have unstable stools. Teniarynchosis can simulate duodenal ulcer or biliary colic. When the segments of the chain are moving through the bauginian flap between the small and large intestines, a cramping pain syndrome occurs. Adult individuals of the tapeworm and their segments can penetrate into the appendix, pancreatic duct and biliary tract, causing their obstruction and inflammatory changes. Intestinal blockage by helminth tangles in multiple invasions can lead to the development of intestinal obstruction. Parasitization of the tapeworm in the gastrointestinal tract contributes to the disruption of metabolic processes, leading to a deficiency of minerals and vitamins. Patients with teniarynchosis constantly experience a feeling of hunger, their appetite sharply increases, with prolonged invasion, body weight decreases.
The products of helminth metabolism have a strong toxic effect, cause sensitization of the host organism, an increase in eosinophilia, local and general allergic reactions (urticaria, hypersensitivity of immediate and delayed type). Asthenovegetative symptoms may be noted: weakness, fatigue, headache, sleep disorders, dizziness, irritability. Functional cardiovascular disorders (tachycardia, moderate arterial hypotension) are possible. With a complicated course of teniarynchosis, mechanical intestinal obstruction, cholecystitis, cholangitis, pancreatitis, peritoneal abscesses, appendicitis may occur. Teniarynchosis aggravates the course of pregnancy: women may develop anemia, toxicosis, miscarriage, premature birth.
Diagnosis and treatment
Diagnosis of teniarynchosis is difficult due to the low specificity of clinical signs. It seems important to conduct an individual delicate survey of the subject in order to establish the facts of active crawling of parasite segments from the anus or their presence in feces during defecation. If an invasion is suspected, the analysis of feces for eggs and fragments of the strobila of helminths – coproovoscopy is of primary importance. Due to low-intensity invasion, enrichment methods are additionally used (Fulleborn deposition method, Kalantarian flotation method), thick smear method (Kato method). In the diagnosis of teniarynchosis, perianal-rectal scraping and an imprint on a sticky tape are informative. The detection of eggs with oncospheres does not allow you to accurately specify the type of tapeworm (bovine or pig), the determination is carried out only up to the teniid family. To clarify the diagnosis of teniarynchosis, morphological signs of isolated mature segments of the parasite are studied (the number of lateral branches of the uterus in bovine tapeworm is 18-32 on one side). With contrast radiography of the small intestine, the helminth is detected in the form of a band of enlightenment. Blood test in some patients with teniarynchosis shows a slight eosinophilia, leukopenia and hyperchromic anemia.
Teniarynchosis is differentiated from other intestinal cestodoses: teniosis and diphyllobothriosis. If necessary, a gastroenterologist is consulted, and if symptoms of intestinal obstruction develop, a surgeon is consulted.
Treatment of teniarynchosis consists in deworming and can be carried out on an outpatient basis with mandatory parasitological control of the effectiveness of therapy. Antihelminthic drugs are prescribed to a patient with teniarynchosis (the main one is niclosamide, the additional one is praziquantel). During treatment, a slack-free diet, setting cleansing enemas, taking saline laxatives, herbal remedies (pumpkin seeds, dry extract of male fern) is indicated. After taking an anthelmintic agent, the tapeworm dies and is excreted naturally during the act of defecation. The criteria for the effectiveness of the treatment of teniarynchosis are the absence of helminth segments in the feces during the next 3-4 months. If the isolation of parasite segments continues, a repeated course of treatment with the same drugs is prescribed.
Prognosis and prevention
After healing, the prognosis of teniarrhosis is usually favorable. Prevention of the incidence of teniarrhosis includes a complex of medical and veterinary measures. Annual surveys are conducted among livestock breeders, their family members, workers of slaughterhouses, meat processing plants, cooks to identify those infected with bovine chain. If necessary, deworming is carried out with disinfection of the released helminths and dispensary monitoring of those who have been ill with teniarynchosis for 6 months. Sanitary and epidemiological supervision consists in protecting the environment from contamination by parasite eggs (monitoring the conditions of keeping animals in individual farms, arranging toilets). Sanitary education of the population is aimed at excluding raw beef from food, compliance with the technology of cooking meat dishes (careful inspection of meat before cooking, sufficient heat treatment of meat products). Detection of finnosis in animals (veterinary and sanitary examination of meat), sanitary and veterinary propaganda is carried out.