Ankylostomidosis( ankylostomiasis and necrotic) - Causes, symptoms and treatment. MF.
Jun 15, 2018
Ankylostomidosis affects up to 30% of the world's population, and are quite widespread in countries with hot climates.
Ankylostomidosis is geogelmintosis( the eggs mature in the environment in the soil), including diseases caused by nematodes of the Ancylostomae Looss family, which include ankylostomiasis and non-caratosis with a similar clinical picture.
The geographic distribution of ankylostomidosis is due to the presence of endemic foci of predominantly subtropical and tropical countries - South Asia, Africa, Central and South America, Australia, where up to 45-50% of the local population is affected. Periodically, ankylostomiasis occurs in countries with a temperate climate( Italy, Serbia, and others).Among neighboring countries, epidemic reports include Georgia, Azerbaijan, Turkmenistan, Kazakhstan, and Uzbekistan. In Russia, these are mainly southern regions - the Krasnodar Territory and others.
Causes of ankylostomidalosis
Pathogens: are roundworms( the so-called nematodes) from the Ancylostomae Looss family and include: Ancylostoma duodenale( dvenadtsatipistra),
Necator americanus( American curvature).
Sexually mature female hookworm
These are obligate human parasites( parasitize only in humans).It is pale pink with round worms with a curved front end. Sewing dimensions - up to 11 mm male, up to 14 mm female. The dimensions of the nekator are up to 8 mm male, up to 10 mm female. At the head end there is an oral sucker for attachment to the intestinal wall. Oral sucker with hookworm contains chitinous teeth in an amount of 6 pieces, and a noncathore - two chitinous cutting inserts.
Oral sucker of
worm In the caudal end, there is a sexual bag( bursa).Eggs hookworm and nekatora virtually indistinguishable from each other, an oval shape with a colorless shell. Their size varies from 34-39 to 56-66 microns. In fresh eggs, blastomeres in the number of 4-8 can be identified.
The structure of the
worm The source of infection is a sick person who excretes helminth eggs with feces. There are experimental data on the infection of dogs, cats, monkeys. An adult specimen of the worm lives in the small intestine of a person, attaching itself to the oral sucker. Every day, sexually mature, fertilized females can excrete up to 30,000 eggs, depending on the type of parasite. Life expectancy of helminth ankylostoma is up to 8 years, non-cyst is up to 15 years.
The mechanism of infection of in ankylostomiasis is fecal-oral, and with non-carotene - percutaneous( percutaneous).Ways of infection - water, food, contact. Factors of helminth transfer in ankylostomosis are contaminated with soil particles with helminth larvae, vegetables and fruit crops, various greens, berries. At non-katorosis infection occurs when walking barefoot on the ground, rest on the ground, earthworks and other types of recreation and work related to the direct contact of the larvae from the soil with the human skin. In this regard, groups of risk are identified for invasion: children, often running barefoot, agricultural workers, gardeners, gardening workers, where the temperature and humidity are high.
The susceptibility of the population to ankylostomidosis is high.
Development cycle. With feces, eggs of helminths are secreted into the external environment, which, after 24-48 hours under favorable conditions( t = 27-30 °, high humidity 70-80% for a non-kilator, 80-100% for hookworm, access of free oxygen) livelarvae, living in the soil. However, they are not yet invasive. Under these favorable conditions, within 7-10 days, the larvae ripen to the invasive stage, and they are mobile. The viability of the larva in the upper soil layers reaches up to 8 weeks in countries with tropical climates. If the conditions are uncomfortable for larvae( moderate climate), then the terms are lengthened( metabolism slows down).
Fecal-oral( more often ankylostoma) and percutaneous or transdermal( more often necator) way enter the human body. In the intestine, hookworms develop to the mature stage, which occurs within 4-5 weeks. In a nekator, the larvae penetrate into the blood vessels, then enter the small circle of the circulation, find themselves in the lungs( alveoli, bronchi, trachea, nasopharynx) - this process is called "migration of the larvae," and then the larvae swallow and ripen in the intestine. The entire process of development of a sexually mature specimen of nekator is up to 8-10 weeks. If the nekator first penetrates through the mouth, then through the mucous membrane of the oropharynx the larva penetrates into the circulatory system. Sexually mature individuals parasitize in the duodenum and in the upper parts of the small intestine. Fertilized females lay 30,000 eggs( hookworms) and 9,000 eggs( nectar).
Helminthes are hematophagous( they penetrate into the intestinal mucosa, they release the substance with anticoagulant properties and feed on the blood flowing from the wound).Ankylostomas live up to 5 years, nekatory - up to 15 years.
Pathogenic effect of hookworm and nekator on the human body
1) In the early phase of the disease, there are toxic and allergic manifestations( hives, bronchitis, eosinophils in the blood reach up to 60%), and the appearance of skin dermatitis at the site of the introduction of larvae. The duration of the manifestations may be 1-2 weeks.
2) In the chronic or intestinal phase of parasitosis, anemia is iron deficient due to vascular damage, splash of anticoagulants, bleeding. The level of blood loss depends on the degree of invasion. Folic acid deficiency, hypoalbuminemia, or a decrease in serum albumin levels may occur( this may be due to blood loss, or impaired absorption of amino acids in the intestine, or protein deficiency in food).Within a day, hookworms can consume up to 0.35 ml of blood, an incubator up to 0.05 ml.
3) There is a mechanical damage to the mature individuals of the intestinal wall with a violation of the motor and secretory functions of the gastrointestinal tract.
Symptoms of ankylostomidosis
The incubation period( the period from the moment the larvae enters the human body before the onset of symptoms of the disease) is 30 to 60 days. The disease can be asymptomatic, but still distinguish several features.
In the early( acute) phase of , there is a general allergic reaction of the body to the products of life and the introduction of larvae. In places of implantation there are phenomena of dermatitis. The patient has severe itching, polymorphous( various) rashes on the skin, swelling, erythema( redness).Possible secondary infection of the elements due to itching and scratching. Dermatoses last up to 10 days. In this phase, changes in the state due to the migration of the larvae can be observed, namely, changes in the respiratory system - cough, asthma attacks, pneumonia;X-ray - eosinophilic inflammatory infiltrates, accompanied by fever and high eosinophilia in the blood( up to 30-60%).
Nescatarosis, manifestations on the skin
Chronic phase( 30-60 days after the invasion) is characterized by two pathological conditions: the development of anemia and the damage to the digestive system.
Anemia has a hypochromic iron deficiency. With an increase in the severity of anemia, there are subjective symptoms: general weakness, fatigue, dizziness, tinnitus. Objectively: the pallor of the skin, sometimes peripheral edema, hypotension( lowering blood pressure), tachycardia( increased heart rate), systolic noise when listening to cardiac tones, expanding the boundaries of the heart. On the ECG - myocardial dystrophy.
From digestive disorders in patients are recorded: decreased appetite, nausea until aversion to food, abdominal pain( pain associated with duodenitis, periduodenitis, etiitis - inflammatory changes in the intestinal wall).There may be diarrhea or constipation. X-ray - a violation of the motor function of the gastrointestinal tract.
Changes in the nervous system are observed in the chronic phase( irritability, sleep disturbance, fatigue, in women - menstrual cycle disorders).
In the general blood test: decrease in the number of erythrocytes, a decrease in hemoglobin( up to 2-3 g%), c / p 0.3-0.5, microcytosis, anisocytosis, poikilocytosis, an increase in reticulocytes. With eosinophilia( in varying degrees of severity) and anemia, leukopenia and disproteinemia( decrease in albumins) are observed.
The prognosis for ankylostomiasis is favorable. With timely diagnosis and treatment, recovery comes. In rare, neglected cases, severe illness and an unfavorable outcome may occur.
Diagnosis of ankylostomiasis
The diagnosis of ankylostomidosis is made on the basis of the following criteria:
1) careful collection of epidemiological history( hygiene violations, visits to cottages and vegetable gardens and food without proper sanitation of hands and products, the possibility of contact with soil, certain occupations at risk -agricultural workers, miners, and others);
2) clinical symptoms of the disease, characteristic of a particular phase of helminthiosis;
3) changes in the general analysis of blood( eosinophilia up to 30-60%, reduction of red blood cells and hemoglobin, color index, reticulocytosis and others), disturbances in the protein spectrum - decrease in blood serum albumins;
4) changes in radiography( changes in the lungs - eosinophilic infiltrates, intestinal hypotension and motor disorders with stagnant stool phenomena);
5) coprovooscopy - detection of helminth eggs in the feces and macroscopy( analysis of the adult parasite), and identification of parasites is possible only after deworming and withdrawal of adult individuals, as it is impossible to distinguish them from eggs.
Treatment of ankylostomidosis
Etiotropic treatment is prescribed by a doctor and is conducted under the control of the condition of the patient's blood count. Drugs have contraindications and side effects! Treatment is often performed on an outpatient basis, but in severe cases - in a hospital.
1) the drug of choice - pyrantel( helminthox, kombantinrin) 10-12 mg / kg / day during meals
2-3 day course, which is determined by the doctor.
2) naphthamone once: children under 5 years - 2-2.5 g, children over 5 years - 5 g. Stir with warm
sugar syrup on an empty stomach 1-2 hours before breakfast.
3) levamisole( decaris) - children under 14 years of age - 2.5 mg / kg, over 14 years and adults - 150 mg once.
4) Vermox( mebendazole) - 100 mg( 1 table) 2 cuts per day for 3 days.
Pathogenetic and symptomatic treatment implies the appointment of iron preparations,
preparations of folic acid, vitamin B12, sedatives, antihistamines and others. Transfusion of blood products according to indications.
The control of the effectiveness of therapy is carried out no earlier than 3 to 4 weeks after the therapy, the feces are examined 3 times with an interval of 4 weeks.
Clinical examination of patients with ankylostomiasis is carried out annually for 4 years, and non-coronary patients - annually for 7 years.
Prevention of ankylostomidalosis
1) Compliance with personal hygiene( washing hands after the toilet and before meals, washing the feet in the performance of gardening, careful treatment of vegetables, fruits, berries before consumption).
2) Timely detection of symptoms of ankylostomiasis, de-worming and examination.
3) Sanitary cleaning of environmental objects and mines from sewage. Small areas of soil, presumably contaminated by hookworm larvae and nekatora treated with salt and boiled water.
4) Annual medical examination of at-risk groups for the incidence of ankylostomidosis( mining workers, agricultural workers and others).
Doctor infectious diseases Bykova N.I.