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Trichostrongyloidosis: causes, symptoms, diagnosis, treatment
Last reviewed: 20.11.2021
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Trichostrongyloidosis is zoonosis-geogelmintosis. Man is an optional host. Adult helminths are localized in the small intestine of a person.
Causes of trichostrongyloidosis. In humans, parasitizes mainly Trichostrongylus colubriformis. Trichostrongylids are small nematodes measuring 4-8 x 0.78-1 mm. Oral opening is limited to three lips. The males at the posterior end have a bursa, two brownish spicules of unequal size and a handlebars guiding their movement.
Eggs of helminths are oval, size 74-80 x 40-43 microns, covered with a thin transparent membrane, with one slightly pointed, and the other with a blunt end.
The cycle of development. Trichostrongylids parasitize, as a rule, in the body of obligate hosts - small and large cattle and other herbivorous mammals. Sometimes a person becomes infected, which is an optional host for this helminth. A person becomes infected with trichostrongyloidosis when eating plants polluted by invasive larvae. Development occurs without migration. In the intestine of a human, the larvae penetrate into the mucous membrane of the duodenum, develop, twice shed and become sexually mature helminths. After 20-30 days in the feces of the patient, eggs can be found. The life expectancy of helminths is more than 8 years.
Epidemiology of trichostrongyloidosis. The role of man as a source of infestation is low. Larvae enter the human body quite rarely and in small quantities.
Trichostrongyloidosis occurs in countries with warm and humid climates in Southeast Asia, North Africa, the Middle East, South, Central and North America, Armenia, Azerbaijan, Uzbekistan, the Volga region, and the Far East. Of the numerous available trichostrongylid species, an infestation of 13 species was detected in humans. Most often sick in the countryside with well-developed livestock. The source of infection - herbivorous animals, large and small cattle, contaminating eggs pasture helminths, cattle yards, stalls. In the external environment, in larvae, under favorable conditions (sufficient humidity, the presence of oxygen and an optimum temperature of 30-32 ° C), larvae develop. After 1-3 days they come out of the egg shells, moult twice, and within 4-14 days turn into invasive, filariform larvae. In the environment, larvae can survive for 3-4 months. They can carry out vertical and horizontal migration and remain viable in the soil for a year. Factors of transmission of the pathogen are vegetables, fruits, herbs contaminated by helminth larvae during agricultural work.
Infection with trichostrongyloidosis occurs when eating fruits, vegetables, sorrel and other herbs contaminated by nematode larvae. A person does not play a big role in spreading this disease.
Pathogenesis. Helminths, penetrating the mucous membrane of the duodenum and jejunum, injure it. Symptoms arise due to the toxic-sensitizing effect of nematodes, and inflammatory processes can also develop.
Symptoms of trichostrongyloidosis
The intensity of invasion in humans is usually low. The course of trichostrongyloidosis is asymptomatic or subclinical. With intense infection, the symptoms of the lesions of the gastrointestinal tract predominate. Patients report a lack of appetite, nausea, eructations, abdominal pain, diarrhea, irritability, weakness, weight loss. Sometimes hypochromic anemia, leukocytosis, eosinophilia develop.
Differential diagnostics. Differential diagnosis is performed with ankylostomidosis.
Laboratory diagnostics. The diagnosis is made when eggs are found in feces. Apply the method of enrichment, since the intensity of infestation is low. Cultivation of larvae on filter paper using the Harada and Mori method is also used. Sometimes eggs of helminths are found in duodenal contents.
Complications. Severe anemia, cachexia.
Treatment of trichostrongyloidosis. Treatment is carried out with a wide spectrum of action nematocides (albendazole, mebendazole, medamin, pyrantel, etc.) using the same regimens as in ascariasis.
Prevention. Prevention is similar to the prevention of other geogelmintoses (ascariasis, ankylostomidosis, etc.).
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