| disease | Hookworm Disease |
| alias | Mulberry Leaves Yellow, Hookworm Disease |
Among the nematodes in the human digestive tract, hookworms are the most harmful. Due to their Chinese Taxillus Herb, hookworms can cause chronic blood loss in humans, leading to anemia and related symptoms.
bubble_chart Epidemiology
Hookworm disease is one of the most widely distributed parasitic diseases in the world, prevalent in Europe, the Americas, Africa, and Asia. The infection rate remains relatively high, with some areas reaching over 50%. Generally, it is believed that the prevalence is higher in the south than in the north, and higher in rural areas than in urban areas. In the north, Ancylostoma duodenale is the dominant species, while in the south, Necator americanus predominates, though mixed infections are extremely common.
bubble_chart Pathological Changes
1. Lesions and symptoms caused by larvae: After the infective larvae penetrate the skin, the patient may experience a sensation of pricking, burning, and intense itching at the local site within tens of minutes. This is followed by the appearance of congestive spots or papules. Within 1–2 days, redness, swelling, and blisters develop, which may exude a pale yellow fluid when scratched. If secondary bacterial infection occurs, pustules may form, eventually healing through scabbing and peeling. This process is commonly referred to as "ground itch."
2. Lesions and symptoms caused by adult worms: Adult worms attach to the intestinal mucosa with their buccal capsules, causing scattered bleeding points and small ulcers, and sometimes forming patchy hemorrhagic ecchymoses. The lesions may extend deep into the submucosa or even the muscular layer. The primary harm of hookworms to the human body stems from the blood-sucking activity of adult worms, leading to chronic blood loss over time. The continuous depletion of iron and proteins results in anemia. Due to iron deficiency, the synthesis of hemoglobin lags behind the production of new cells, causing red blood cells to become smaller and paler in color, resulting in hypochromic microcytic anemia.
1. Pathological changes and symptoms caused by larvae
(1) Hookworm larval dermatitis: The dermatitis commonly occurs in areas with thinner skin that come into contact with soil, such as between the toes and fingers, and can also appear on the backs of the hands and feet.
(2) Respiratory symptoms: When the larvae migrate to the lungs and penetrate the capillaries to enter the alveoli, they can cause local bleeding and inflammatory changes. Patients may experience cough, blood-streaked sputum, and often systemic symptoms such as chills and fever. Severe cases may present with persistent dry cough and asthma. If a large number of larvae infect the body at once, it may lead to fulminant hookworm-induced asthma.
2. Pathological changes and symptoms caused by adult worms
(1) Digestive tract lesions and symptoms: In the initial stage, patients mainly exhibit upper abdominal discomfort and dull pain, followed by symptoms such as nausea, vomiting, and diarrhea. Appetite often increases significantly, while body weight gradually decreases. A small number of patients may develop unusual cravings for raw rice, raw beans, or even soil, coal cinders, or rags, a condition known as "pica." The cause may be a neuropsychiatric allergic reaction, likely related to iron deficiency in the body. In most patients, this phenomenon disappears after iron supplementation.
(2) Anemia: Patients may display waxy yellow skin, pale mucous membranes, dizziness, and weakness. In severe cases, even mild activity can cause palpitations and shortness of breath. Some patients may experience facial and systemic edema, particularly in the lower limbs, as well as pleural effusion, pericardial effusion, and other manifestations of anemic heart disease. Muscles become slack, reactions slow, and eventually, the patient loses all ability to work. Women may experience amenorrhea or late abortion.
(3) Infant hookworm disease: The most common symptoms include tarry black stools, diarrhea, and loss of appetite. Signs include pale skin and mucous membranes, systolic murmurs in the apical region of the heart, occasional rales in the lungs, and hepatosplenomegaly. Additionally, infant hookworm disease has the following characteristics: severe anemia, with red blood cell counts below 2 million/mm³ in 80% of cases and hemoglobin levels below 5g%; significant increases in both the proportion and absolute count of eosinophils; poor development in affected children and multiple complications (such as bronchopneumonia and intestinal bleeding); and a high mortality rate. Reports indicate that severe anemia and acute intestinal bleeding caused by hookworms are among the most common causes of death in infants aged 1–5 years. The mortality rate for infants under 1 year is 4%, and for children aged 1–5 years, it can reach 7%, warranting serious attention.bubble_chart Auxiliary Examination
Common methods include the direct smear method: simple and easy to perform, but grade I infections are easily misdiagnosed as fistula disease, and repeated examinations can improve the positive rate; the saturated saline flotation method: hookworm eggs have a specific gravity of about 1.06 and easily float in saturated saline (specific gravity 1.20). The detection rate is significantly higher than that of the direct smear method. During large-scale surveys, 15% or 20% saline can be used, with the same effectiveness as saturated saline; the hookworm larva culture method: the detection rate is similar to that of the saline flotation method, and this method can identify the species of the parasite, but it requires 5–6 days of cultivation to yield results. Additionally, the saturated saline flotation method and the hookworm larva culture method can also be used for quantitative examinations.
In endemic areas, if symptoms such as cough and asthma appear, sputum and blood tests should be conducted. The presence of hookworm larvae in sputum and manifestations of microcytic hypochromic anemia can confirm a diagnosis of hookworm disease.
The detection of hookworm eggs in stool or the hatching of hookworm larvae is the basis for diagnosis. Immunodiagnostic methods are used before hookworm egg production and combined with the history of combined diseases for early diagnosis. In endemic areas, the presence of hookworm larvae in sputum and manifestations of microcytic hypochromic anemia can confirm a diagnosis of hookworm disease.
bubble_chart Treatment Measures
In endemic areas, regular mass screening and treatment campaigns should be conducted, preferably during winter and spring. Common vermifugal medications include mebendazole, albendazole, and thiabendazole, which not only kill or expel adult worms but also inhibit the development or kill eggs and larvae. Applying a 15% thiabendazole ointment topically can treat hookworm larval dermatitis, with enhanced effects when combined with diathermy. Immersing the infected area in 53°C hot water for 20-30 minutes may kill migrating larvae in subcutaneous tissues.
After thorough treatment, the absence of clinical symptoms or signs within 2 months, as well as no detection of parasite eggs in stool examination, indicates a cure.
The prognosis of the disease is favorable, with no sequelae.
Treating patients to control the source of pestilence is a crucial step in preventing the spread of hookworm disease. Strengthening fecal management and implementing safe disposal are key measures to block the transmission route of hookworms. Methods such as mixing feces with urine for storage, using sealed biogas digesters, or employing five-compartment three-tank sedimentation systems can effectively kill parasite eggs before the waste is used as fertilizer for dryland crops. When fertilizer is urgently needed, animal manure or chemical fertilizers can serve as alternatives. Enhancing personal protection and preventing infection are also essential. Encouraging the wearing of shoes during fieldwork and applying 1.5% levamisole boric acid alcohol solution or 15% thiabendazole ointment to the skin of hands and feet can help reduce the risk of infection. Whenever possible, mechanized labor should replace manual work to minimize exposure and infection opportunities.
Hookworm dermatitis, gastrointestinal bleeding
