So called nematode diseases
Ancylostomatidae family. In humans, two parasites
A representative of this family is an ankylostoma (Arcylostoma
duodenale), which causes the disease called hookworm, and
necator (Necator americanus) calling
The size of the parasites ranges from 5 to 18 mm. Both worms,
morphological structure of which is different, similar in biology and
pathogenicity. The oral capillary capsule is equipped with chitin
cutting teeth, and necator – cutting plates. Males
differ in the structure of the tail end, and females – the location
Hookworm eggs and necators in external structure practically
indistinguishable from each other. In the adult state of parasites
localized in humans in the duodenal ulcer and the upper part of the thin
intestines, firmly fixed to the mucous membrane of their walls. Eggs
excreted with feces out, under favorable conditions in
1-2 days to ripen to the stage of larvae that leave
eggs and live some time in the soil.
Developing and undergoing several molts, the larvae become
invasive. They are capable of movement and can penetrate the soil.
to a depth of almost one meter and climb through the wet grass,
its branches and stems, to a height of 15-20 cm. Invasive larvae
actively implemented through intact human skin deep into
Penetration occurs most often through the skin of the legs when walking
without shoes, as well as through the skin of other parts of the body while lying on
the earth. Once in the tissues, the larvae enter the blood vessels and
passively moving with blood. Being brought into the capillaries of the lungs, they
penetrate their wall into the alveoli.
The ciliated airway epithelium drives them out of the small
bronchi up into larger, then along the trachea and larynx; hitting
pharynx and mouth, larvae can be swallowed; reaching the intestines
they are attached to the mucosa of its wall and begin to grow. Later
4-5 weeks from the moment of infection the larvae grow into adults
sexually mature parasites. From this moment begins the laying of eggs.
Infection is possible through the mouth with food contaminated by the larvae.
hookworm. В этом случае они не мигрируют, а, hitting кишечник,
can directly develop in it in adults. Larvae
necator migrates with both methods of penetration into the body.
The lifespan of hookworm and necator is about 5 years.
Hookworms are common in the tropics and subtropics, where for
development of eggs and larvae in the environment are favorable
humidity and temperature conditions.
Hookworm development can occur in moderate and even in
a cold climate, but not on the surface of the soil, but deep underground,
in wet mines where the temperature is kept all year round within
18 ° and above.
Pathogenesis and clinic
Pathogenesis and clinic различны в период миграции и во время
stay of adult parasites in the intestines. The introduction of larvae into the skin
may cause her redness and itching sensation. In addition, in persons
re-infecting, you may experience an allergic reaction with
the same phenomena or with the phenomenon of edema, rash. These symptoms
often flow unnoticed. Migration of larvae to the lungs
accompanied by pinpoint and sometimes stronger hemorrhages.
It is also possible the development of bronchitis and even bronchopneumonia.
Adult hookworms, attaching to the intestinal walls, violate
mucosal integrity and feed on blood. They highlight a special secret
which prevents blood from clotting, which can cause
prolonged bleeding from damaged mucosal sites. Being
able to move, parasites usually in many places
damage the mucosa.
The process is aggravated by the possibility of the penetration of microbial flora and
the appearance of inflammatory changes. All this leads to a violation
gastrointestinal function. There are pain in the intestines, violations
stool, appetite, patients with nausea and vomiting. Blood loss
leads to depletion of iron, protein, vitamins, mainly
A, D and B complex, and to the development of anemia and even cachexia.
In children with reduced nutrition, especially when eating food,
poor in proteins and iron, the disease takes a severe form
reflecting on their mental and physical development. It proceeds
more severe with prolonged and intense invasion. In these cases,
in addition to violations of the gastrointestinal tract, children have a general
weakness, easy fatigue, shortness of breath.
They become lethargic, apathetic. The skin becomes swollen,
pale with a waxy tinge, mucous membranes are also very pale.
Observed nosebleeds, appetite distortion – need
there is chalk, clay, etc. There are other signs of severe
iron deficiency anemia – coilonychia, achiliah esophagitis.
Systolic murmur is heard in the heart, anemic –
on the bulb of the jugular vein. With prolonged anemia develop
symptoms of degeneration of the heart muscle. In the blood of patients are observed
changes, characteristic of hypochromic anemia: decreased hemoglobin,
sometimes up to 10% with a small number of erythrocytes (below 1 million) and low
color index. The number of eosinophils is almost constantly increased – in
average from 10 to 20%.
Diagnosis анкилостомидозов может быть точно поставлен на основании
finding eggs in feces. Eggs are easy to spot and keep.
Duodenal ulcer in duodenal intubation. Last method
more accurate and useful in doubtful cases.
Treatment анкилостомидозов проводится нафтамоном, комбантрином или
levamisole. For severe anemia, iron preparations are shown, and
also red blood cell transfusions. Treatment продолжается в течение
3 days. Efficiency is about 80%.
Prevention сводится к охране внешней среды от загрязнения
faeces and to use for fertilizing the land exclusively
neutralized feces. In addition, it is necessary to identify and treat all individuals
For the purpose of personal prophylaxis in the foci of ankylostoma
allow children to walk barefoot, lie down and sit on uncovered
the earth. Vegetables and fruits, eaten raw, necessary
wash thoroughly and immerse in about one minute