Lambliosis

Lambliasis (giardiasis; English name - Giardiasis) is a protozoan invasion, which often occurs as an asymptomatic carrier, sometimes with functional intestinal disorders.

ICD-10 code

A07.1. Giardiasis (giardiasis).

Epidemiology of giardiasis

The source of infection is a person who excretes mature cysts of lamblia with feces. The possibility of human infection with Giardia lamblia strains from animals (the pathogen has been found in dogs, cats, rabbits and other mammals) currently has insufficient evidence. The mechanism of infection is fecal-oral. The main route of transmission is water. The degree of contamination of the environment with feces is a decisive factor in the level of giardiasis in the population. In children's institutions, the contact-household route of infection is of great importance. Group outbreaks are usually caused by fecal contamination of water, less often food. Giardia cysts have been found in the intestines of some insects (flies, cockroaches, mealworms), which can contribute to their spread.

Giardiasis is found everywhere, but the highest incidence of the population is noted in countries with a tropical and subtropical climate. In these countries, Giardia is one of the most common causative agents of traveler's diarrhea. The disease is registered in all age groups. Infectious disease specialists assume that adults develop a certain protective immunity in endemic foci. In our country, the majority of infected people (70%) are preschool and primary school children. The spring-summer seasonality is most pronounced, the smallest number of cases are registered in November-December.

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What causes giardiasis?

Giardiasis is caused by Lamblia intestinalis (Giardia lamblia), which belongs to the subkingdom Protozoa, subtype Mastigophora, order Diplomonadida, family Hexamitidae.

In the development cycle of the protozoan, two stages are distinguished - the vegetative form and the cyst. The vegetative form is a trophozoite measuring 8-18x5-10 µm, pear-shaped. The posterior end is narrowed and elongated, the anterior end is widened and rounded; the ventral side is flat, the dorsal side is convex. The trophozoite is characterized by a bilaterally symmetrical structure. It has four pairs of flagella, two nuclei with karyosomes and a so-called suction disk - a depression with the help of which it attaches to the surface of the epithelial cell of the host's intestine. Lamblia feeds osmotically over the entire surface of the body, absorbing nutrients and various enzymes directly from the brush border. The maximum number of parasites is found in the proximal part of the small intestine (initial 2.5 m), where the intensity of parietal digestion is highest. Lamblia do not parasitize in the bile ducts, since concentrated bile has a detrimental effect on parasites. Reproduction occurs by longitudinal division of the trophozoite. The process of cyst formation takes 12-14 hours. A mature cyst is oval in shape, 12-14x6-10 μm in size. It contains four nuclei. Cysts excreted with feces are resistant to environmental factors: in water at a temperature of 4-20 C, they remain viable for up to 3 months. Like amoeba cysts, they are resistant to chlorine.

Pathogenesis of giardiasis

Symptoms of giardiasis depend on the infective dose, the functional state of the gastrointestinal tract and the immune status of the body. An increase in the number of giardia is facilitated by food rich in carbohydrates, a history of gastric resection and a decrease in the acidity of gastric juice. A protein diet prevents the reproduction of giardia. Trophozoites live in the duodenum, attaching themselves with the help of suction discs to the epithelial cells of the villi and crypts. They do not penetrate the intestinal mucosa, but the suction discs form depressions on the microvillous surface of the epithelial cells. Parasites feed on the products of parietal digestion and can reproduce in the intestine in huge quantities. In places of giardia parasitism, mitotic processes intensify and mature, functionally complete cells are replaced by young, immature ones (frequent replacement of epithelium); as a result, the absorption of food components is disrupted. These changes are reversible, after recovery from giardiasis the absorption process is normalized. Giardiasis is often accompanied by intestinal dysbiosis, especially the number of aerobic microflora increases. The metabolic products of giardia and the substances formed after their death are absorbed and cause sensitization of the body. Morphological changes in giardiasis are characterized by shortening of the papillae of the mucous membrane of the duodenum and jejunum, a decrease in the depth of the crypts.

Massive invasion by lamblia occurs with immunodeficiency, especially in children with primary hypogammaglobulinemia, selective IgA deficiency. Lamblia are capable of producing IgA proteases that destroy immunoglobulins of this class. Perhaps this is important in the formation of persistent recurrent course of lambliasis resistant to antiparasitic drugs.

Symptoms of giardiasis

A distinction is made between latent giardiasis (without clinical manifestations) and manifest. The vast majority of infected people have no symptoms of giardiasis. The incubation period of giardiasis lasts from 7 to 28 days. Clinically manifest forms develop relatively rarely. The acute period usually lasts several days, after which giardiasis often passes into a subacute or chronic stage with short-term exacerbations in the form of loose stools and bloating, weight loss, and increased fatigue.

The most common symptoms of giardiasis during primary infection are nausea, anorexia, bloating and rumbling in the abdomen. Stool is frequent, foul-smelling, fatty, foamy; vomiting and cramping pains in the epigastric region are possible. This form of giardiasis is relieved in a few days under hygienic conditions and responds well to chemotherapy, but without specific treatment it can become protracted. Some people are predisposed to repeated infection and persistent giardiasis. In these cases, giardiasis lasts for months and years with periodic exacerbations in the form of gastroduodenitis, jejunitis, and gallbladder dyskinesia. Clinical forms with allergic manifestations in the form of urticaria with skin itching, attacks of bronchial asthma with moderate eosinophilia in the blood are known. Children often have neurotic symptoms of giardiasis: weakness, rapid fatigue, irritability, tearfulness, headaches. In tropical and subtropical countries, malabsorption syndrome is registered in patients with giardiasis.

Giardiasis can be complicated by intestinal dysbiosis.

Diagnosis of giardiasis

Laboratory diagnostics of giardiasis involves examination of feces or duodenal contents. Giardia cysts are usually found in feces. Vegetative forms can also be found in feces during diarrhea or after taking a laxative. Duodenal contents are examined to detect trophozoites. For diagnostic purposes, smears-prints of the mucous membrane of the small intestine, biopsy material obtained during endoscopy are also examined. The ELISA method detects antibodies to Giardia antigens.

Differential diagnostics of giardiasis is carried out with helminthic invasions and other diarrheal infections. Consultative assistance is usually not required. Patients are treated on an outpatient basis.

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Treatment of giardiasis

Specific treatment of giardiasis is carried out when giardia is detected and the patient has clinical manifestations. For these purposes, the following tablets for giardia are used.

• Metronidazole. Adults are prescribed 400 mg orally three times a day for 5 days or 250 mg three times a day for 7-10 days: children 1-3 years old - 0.5 g per day for 3 days, 3-7 years old - 0.6-0.8 g per day for 3 days, 7-10 years old - 1-1.2 g per day for 5 days.
• Tinidazole is prescribed orally once, for adults 2 g (can be repeated if necessary), for children - 50-75 mg/kg.
• Ornidazole is taken orally at 1.5 g once a day (in the evening) for 5-10 days; for children weighing up to 35 kg, the drug is prescribed at 40 mg/kg in one dose.
• Nimorazole is prescribed orally at 500 mg twice a day for 6 days.
• Nifuratel is taken orally: adults 400 mg 2-3 times a day for 7 days, children - 15 mg/kg twice a day for 7 days.
• Albendazole. Adults take 400 mg orally twice a day for 7 days; children - 10 mg / (kg x day), but not more than 400 mg, for 7 days. High lambliocidal efficacy of albendazole has been shown, which can be the drug of choice in the treatment of giardiasis in combination with intestinal nematodosis. Treatment of giardia with folk remedies can also be used.

Specific therapy for giardiasis ends with a control study of feces.

Often, an infectious disease specialist prescribes a diet for giardiasis.

Clinical examination

Outpatient observation is carried out according to clinical and epidemiological indications: in case of long-term persistent giardiasis, observation for up to 6 months with two or three parasitological examinations is recommended.

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How to prevent giardiasis?

Prevention of giardiasis is the same as for amoebiasis and other infections with a fecal-oral mechanism of transmission of the pathogen.

Prognosis for giardiasis

Giardiasis has a favorable prognosis.