Hookworm disease (hookworm, necatoriasis) is a helminthiasis that occurs with damage to the gastrointestinal tract and iron deficiency anemia; the causative agents are representatives of the hookworm family, hookworm and necatoriasis .
Content
Prevalence of the disease
In terms of the number of people infected around the globe, hookworm infections rank second after ascariasis. More than 900 million people are infected with them. At the same time, 450 million new cases of the disease are registered annually.
Hookworm infections are common in areas with warm and humid climates. In some countries of South and Central America, Africa, southern Asia, Hindustan, Indochina and the islands of the Malay Archipelago, up to 50% of the population is infected. Limited outbreaks exist in Central Asian countries, the Transcaucasus, Turkmenistan and Kyrgyzstan, western Georgia and Azerbaijan.
On the territory of Russia - on the Black Sea coast of the Krasnodar Territory, on the border with Abkhazia.
In countries with a temperate climate, there are underground foci of hookworm - deep mines of the coal and mining industries, where there are favorable conditions for the development of hookworm larvae.
Routes of infection
The source of environmental contamination by the larvae of these helminths is a sick person; the main transmission factor is soil.
The dispersal of larvae is facilitated
- soil contamination with feces,
- erosion of cesspools by heavy rains,
- as well as the use of undisinfected feces to fertilize vegetable gardens.
Mechanical transfer of contaminated feces particles by domestic animals, birds, and flies is possible.
A sick person does not pose an immediate danger to others, since they secrete hookworm eggs that are not dangerous to others.
People's natural sensitivity is high.
At-risk groups:
- children,
- summer residents,
- agricultural workers,
- miners,
- tourists.
Development of the disease
The pathological effect on the human body is
- the impact of larval antigens on the immune system,
- their mechanical effect on the tissues of those organs through which they migrate,
- “devouring” blood cells by parasites.
As a result of these effects, pinpoint hemorrhages occur in the lungs with infiltration of eosinophils and leukocytes. During the period of migration of individuals, the patient develops toxic-allergic and pulmonary syndromes.
After the worms reach sexual maturity, the chronic (intestinal) phase of the disease begins in the intestines with the development of gastrointestinal disorders and anemia.
Hookworms feed only on blood. When fixed in the intestine, the cutting appendages of the oral capsule capture areas of the mucous membrane, damaging small vessels and capillaries, causing microbleeding. At the site of attachment of the parasite, bleeding ulcers up to 2 cm in diameter are observed. Anticoagulants secreted by the worms' esophageal glands slow down blood clotting, resulting in prolonged bleeding.
The daily blood loss when one individual is parasitized by necator is 0.03-0.05 ml, hookworm - 0.16-0.34 ml.
The level of blood loss and iron loss depends on the intensity of the invasion. Can be parasitic in humans
- several hookworms (low intensity),
- several tens (medium intensity),
- hundreds and thousands (significant intensity) of copies.
At high intensity, the disease is severe, especially in children and adolescents. In this case, it leads to delayed physical and mental development. Children under 3 years of age rarely get sick.
Symptoms
The incubation period of the disease lasts 40-60 days. In most cases, the invasion is asymptomatic; signs of the disease appear in moderate and severe forms of infection.
When the larvae enter through the skin, itching and burning of the skin and a rash occur, which lasts for several months. With the simultaneous penetration of larvae of dog hookworms (A. caninum), a picture of a larva migrating in the skin is observed. Often, foci of infection appear on the skin due to the introduction of pathogenic microflora (streptococci, staphylococci) with purulent inflammation of the skin.
When larvae migrate through the respiratory tract, catarrhal inflammation is possible,
- shortness of breath appears,
- wheezing,
- chest pain,
- hoarseness of voice up to aphonia.
Possible development of bronchitis, pleurisy, pneumonia. Blood tests show eosinophilia.
When hookworms enter the gastrointestinal tract, it develops
- duodenitis with heartburn,
- lack or increase of appetite,
- perversion of taste (desire to eat, for example, clay),
- nausea,
- vomit,
- diarrhea,
- pain in the epigastrium and right hypochondrium.
Often parasitizing hookworms provokes peptic ulcers of the stomach and duodenum .
In children, signs of central nervous system damage are observed:
- lethargy,
- retardation in mental and mental development.
Anemia occurs 3-4 months after infection and is manifested by symptoms such as:
- general weakness,
- dizziness,
- fast fatiguability,
- pallor of the skin and mucous membranes,
- angular stomatitis,
- dry skin,
- brittle nails and hair
- puffiness of the face,
- sometimes swelling in the legs.
With prolonged iron deficiency anemia, dystrophy of the heart muscle increases, accompanied by shortness of breath and tachycardia. In severe cases, retinal hemorrhages occur.
Hookworm infection is especially dangerous in pregnant women, when anemia threatens the life of the woman’s fetus.
Diagnostics
The diagnosis is made by detecting hookworm eggs in the stool. Given that hookworm eggs develop rapidly in feces and, when dividing, become similar to trichostrongylid eggs, the material must be delivered to the laboratory quickly.
Serological methods are not widely used.
In peripheral blood it is determined
- decrease in red blood cells to 10¹²/l,
- hemoglobin up to 70-90 g/l,
- color index up to 0.3-0.5,
- myrocytosis,
- leukocytosis - 15-20x10⁹/l,
- eosinophilia in the initial period - 50-60%, then decreasing to 10-15%,
- increased ESR.
During a biochemical blood test:
- hypoalbuminemia;
- decreased serum iron levels,
- increased iron-binding capacity of blood serum.
Treatment
Treatment is carried out on an outpatient basis or in a day hospital. In case of intensive invasion and decompensated anemia, hospitalization is necessary.
The following drugs are used for therapy:
- albendazole,
- mebendazole,
- carbendacim,
- pyrantel,
- bethenia hydroxynaphthoate.
If necessary, the course is repeated after 2-3 weeks.
In young children and severe anemia, antiparasitic drugs should be given only after the anemia has been corrected. In severe cases (hemoglobin less than 40 g/l), infusion of red blood cells is advisable.
For anemia, iron supplements are used in age-appropriate doses, and if necessary, folic acid.
In case of severe hypoalbuminemia, a 5-20% albumin solution with a volume of 200 ml or fresh frozen plasma is administered - 20 ml/kg body weight per day intravenously at a rate of 50-60 drops per minute, the frequency of administration is determined individually.
Outpatient observation of the patient for 3 months is recommended. To monitor the effectiveness of treatment, 3 scatological studies are carried out 1 month after deworming with an interval of 30 days. Immediately after the course, the number of eggs in the feces may increase due to their arrival from dead mature parasites.
Prognosis and prevention
The prognosis for life is favorable, with the exception of young children with severe anemia.
As a preventative measure, a number of measures are carried out in areas of hookworm infection.
- Improving the sanitary culture of the population, observing the rules of personal hygiene, washing hands, vegetables, berries, recommending not to walk barefoot, not to lie on the ground.
- Identification and treatment of all infected people through mass screening.
- General sanitary measures: improvement of housing, provision of sewerage, dry closets, regular cleaning of toilets, disinfection of the soil with table salt (1 kg of salt dissolved in boiling water, per 1 sq. m, once every 10 days) or potassium chloride.
- To prevent the introduction of hookworms into mines, newly arriving workers are subject to scatological examination.
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