What is Hookworm Disease?
Ankilostomiasis, or miners’ rash, or earthy scabies – helminthiasis (nematodoses), occurring with allergic lesions of the skin, respiratory organs (at the early stage), gastrointestinal tract and iron deficiency anemia (at the late stage).
Causes of Hookworm
Pathogen hookworm – hookworm Ancylostoma duodenale, which belongs to the family krivogolovok – Ancylostoma, suborder or superfamily svaynikovyh (Strongylata Railiet et Rudolphi), class round helminths parasitizing the human small intestine, most often in the duodenum.
Ancylostoma duodenale has a pale pink color when it is alive, white after death.
The female A. duodenale lays 30,000 eggs per day, which develop to the invasive phase after the feces come to the soil surface and stay there at air temperatures not lower than 14 ° C, relative humidity not lower than 70% and rainfall not lower than 1000 mm / year , aeration and shading. At soil temperatures of up to 10 ° C, eggs can remain viable for 6–8 weeks. Under conditions of optimum air temperature of 28–30 ° C in 24–48 hours, the larva of the first phase, the rabditiform, hatches from the egg. After 2-3 days, after molting, it turns into a strong-larva larva (second phase). After 1-2 days, the second molt occurs and the larva turns into filar-like or invasive (third phase). All development of the larva lasts 7-10 days. The invasive larva leads a free lifestyle and in optimal soil conditions it can live up to 8-18 months, according to Manson, even more than 2 years. According to experiments conducted by Matsusaki, hookworm larvae have a longer life span than necator larvae.
Pathogenesis during Hookworm
Infection with ankilostomiasis occurs with the active introduction of the larvae through the skin or if they are swallowed by contaminated vegetables, fruits, and water.
Invasive larvae, penetrating into the human body, are introduced into the right heart and lungs from the alveolar capillaries, where they further mature, into the cavity of the alveoli, from there into the oral cavity and enter the upper part of the small intestine, where their final development occurs. Ankilostomid invasion larvae that have entered the human body through the skin and through the mouth migrate.
The development of larvae, from their introduction to the first egg-laying of adults, lasts 60 days. In the intestine A. duodenale live in some cases. up to 4 years.
In humans, it parasitizes from several instances of ankylostomid (low intensity) to several dozen (medium intensity), hundreds and thousands of copies (significant intensity). The difference in virulence between hookworm and noncator is not particularly sharp.
Ankilostomid larvae are able to climb plant stalks (grass, vegetables, tea bushes, etc.) moistened with rain or dew, to a height of 22-30 cm, which can cause human invasion even when walking in shoes on the grass, while collecting tea sheets, through the skin of the calf, through stockings. The larvae cannot descend back down and die when the moisture on the plants dries. The spread of larvae on the soil surface occurs as a result of washing out of faeces containing eggs, rain and flood waters. This also contributes to the mechanical transfer of particles of feces by domestic animals and birds. Epidemiological significance is gained by the fact that ankylostomid eggs pass through the gastrointestinal tract of coprophages, animals and birds, without losing the ability to further. The epidemiological role of flies, which can contribute to the dispersion of ankilostomid eggs, is not excluded. In this regard, exophilous fly species carrying shigella and other pathogenic microbes are of particular interest. In endemic foci of ankilostomidosis, where the extensiveness of invasion is high, the sputum of persons invasive with ankilostomid may have a certain epidemiological significance. S.A. Muchiashvili successfully infected, through the skin of guinea pigs and hamsters, necator larvae, extracted from the lungs (that is, without a cap), of initially infected animals. Larvae in the secondarily invasive animals were found in the lungs, the trachea and extracted by the Berman method remained vital for 2 hours.
During migration, the larvae cause toxic and allergic phenomena. Adult hematophagous worms. When fixing to the intestinal mucosa, they injure tissues, lead to the formation of hemorrhage, erosion, cause bleeding, anemization, maintain the state of allergy, dyskinesia of the gastrointestinal tract and dyspepsia.
Symptoms of Hookworm
The incubation period is 40-60 days. In most cases, the number of parasites is small, and the disease is asymptomatic. The symptomatology of heavier forms depends on how the parasite penetrates the body.
Many patients feel a moment of massive invasion through the skin of the sole, shin, thigh, buttocks, like a “stinging nettle.” With the simultaneous penetration and pathogenic flora (streptococci, staphylococci, etc.) inflammatory and purulent processes on the skin develop. The larvae can enter into the host organism microbes of tuberculosis, hemorrhagic septicemia, anthrax.
Soon after infection, itching and burning, urticaria, asthma, fever, eosinophilia. In the late stage, nausea, drooling, vomiting, abdominal pain, bowel function disorders (constipation or diarrhea), bloating appear. Sometimes there is pseudo-ulcer syndrome (hunger in the epigastric region, hidden bleeding). Symptoms of CNS damage; lethargy, mental retardation and physical development. The development of gynochromic iron deficiency anemia is characteristic; its severity depends on the intensity of invasion, nutritional deficiencies, and individual characteristics of the organism. In the most severe cases, the number of erythrocytes is reduced to 10×1012 / l, and the content of Hb – to 100 g / l. At low intensity, invasion can occur subclinically, manifesting eoinophilia.
Diagnosis of Hookworm
The diagnosis is based on the detection of eggs in the contents of the duodenum, obtained by duodenal intubation, in feces, as well as on the results of serological reactions – hemagglutination and latex-agglutination.
Treatment of Hookworm
In cases of severe anemia (hemoglobin below 67 g / l), iron preparations and red cell transfusion are used. Worm-cleaning is carried out with naphtamon, combantrin or levamisole. Naftamon is prescribed on an empty stomach for 2-5 days. Single dose for adults 5 g. To eliminate the bitter taste and nausea, the drug is best given in 50 ml of warm sugar syrup. Kombantrin (Pyrantel) is administered in a daily dose of 10 mg / kg in two doses after a meal, and levamisole (decaris) in a daily dose of 2.5 mg / kg in a single dose. Treatment with these drugs lasts 3 days. Efficiency about 80%.
The prognosis is in most cases favorable.
Prevention of Hookworm
In the foci of hookworms should not walk barefoot and lie on the ground without litter. It is necessary to thoroughly wash and scald fruits, vegetables, and berries with boiling water before eating them; you should not drink unboiled water.