Introduction:
Hookworms, whipworms, and Ascaris are parasitic worms accounting for major diseases worldwide. Almost 700 million people in the world are affected by hookworms. However, the advancements in living conditions have reduced the infection rate. The two species causing hookworm infection are Ancylostoma duodenale and Necator americanus.
What Are the Causative Agents for Hookworm Infection?
The parasites causing hookworm infection in humans are:
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Ancylostoma duodenale.
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Ancylostoma ceylanicum.
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Necator americanus.
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Ancylostoma caninum.
The hookworms affecting the animals are:
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Ancylostoma braziliense.
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Ancylostoma caninum.
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Uncinaria stenocephala.
What Is the Pathogenesis of Ancylostomiasis?
The eggs of hookworm are passed in the infected person's fecal matter. Under moist, warm, and shady conditions, the eggs hatch in one to two days and form larvae, which live freely in the soil. The current form of larvae formed after one to two days is called the rhabtidiform larvae which grow in the feces or soil and develop into filariform larvae, the infective type, in five to ten days.
The filariform larvae can survive in environmental conditions for about three to four weeks. For example, when humans walk barefoot in contaminated soil, the filariform larvae penetrate the skin and enter the bloodstream to reach the heart and lungs.
The larvae reach the intestine by penetrating the pulmonary alveoli, climbing up the bronchial tree, entering the pharynx, and getting swallowed. Then, they reach the small intestine and reside in the jejunum to mature into adult worms. This parasite’s attachment results in blood loss. Most commonly, the worms are released in one to two years.
A few Ancylostoma duodenale larvae remain dormant in the intestine and muscle after skin penetration. They can re-activate at any time and cause intestinal infections. In addition, they can get transmitted through oral ingestion. Ancylostoma ceylancium and Ancylostoma caninum also spread through oral ingestion and not by penetrating the skin.
What Are the Signs and Symptoms of Ancylostomiasis?
The majority of the infected people do not have symptoms. However, the people infected for the first time show itching and rash, which occur when the mature worm penetrates the skin. In severe cases, gastrointestinal symptoms include abdominal pain, loss of appetite, diarrhea, fatigue, and weight loss. In addition, the severe complication of ancylostomiasis is blood loss due to the parasite's attachment to the intestine, resulting in anemia and protein loss. Moreover, asymptomatic pneumonitis can occur if the worms reach the lungs through the bloodstream. However, they finally reach the intestines to exert gastrointestinal symptoms. In children, cognitive and physical development are impaired.
Who Is at Risk for Ancylostomiasis?
Contaminated soil is the main route of disease transmission. In most places, feces are used as fertilizers. Therefore, people who walk barefoot in the soil, especially in areas where hygiene maintenance is poor, are at a higher risk of getting infected.
How Is Ancylostomiasis Diagnosed?
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Stool Examination: The stool samples collected from the infected person can microscopically help diagnose thin-shelled hookworm eggs. In light infections, the eggs are not usually visible. In such cases, concentration procedures can be conducted. In some cases, if the collected stool sample is not placed in favorable conditions, the eggs may hatch into larvae, and identification and differentiation from other parasites can be challenging. However, molecular tests help differentiate the hookworms causing infection in humans.
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Blood Examination: Blood tests reveal eosinophilia (increased number of eosinophils) when infected with hookworms. This can be the only identification for the first few days after penetration of the larvae. In addition, the decrease in iron content in the blood is a significant finding.
What Is the Treatment for Ancylostomiasis?
Ancylostomiasis can be treated using antihelmintic drugs prescribed by the healthcare provider. The common drugs administered are Albendazole, Mebendazole, and Pyrantel pamoate. These drugs are effective; however, they may have side effects. In addition, Ivermectin, the most commonly used antihelmintic drug, is ineffective in treating ancylostomiasis. The symptoms of the condition can be treated separately. For example, anemia due to extreme blood loss can be treated using iron supplements.
Why Is Mass Drug Administration Carried Out?
Mass drug administration is a process of treating many conditions together. For example, hookworm, Ascaris, whipworm, schistosomiasis, lymphatic filariasis, river blindness, and trachoma are treated together as the drugs are safe and not so expensive. Hence, the risk groups are selected every year for mass drug administration. This process is primarily used for neglected tropical diseases.
How Can We Prevent Ancylostomiasis?
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Avoiding Contact With the Soil: Ancylostomiasis usually spreads through direct contact with the contaminated soil. Hence, avoid walking barefoot in the soil; instead, use protective shoes. In addition, do not defecate in the fields or use human feces as fertilizers. This action increases the chances of infection in children playing in the soil. Hence, install proper sewage disposal systems in living areas. To recapitulate, one can take significant measures to prevent contact with the soil.
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Preventive Treatment: As the name says, treatment is provided to individuals before testing the stools, primarily to prevent infection. For this purpose, the World Health Organization selects high-risk groups, such as school children, pregnant women, lactating women, and people with occupational risks. It treats them against hookworm, ascaris, and whipworm infection. The children get treated through school health programs and pregnant and lactating women from healthcare centers.
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Treat the Pets: One best way of prevention is to treat cats and dogs at home, as they can transmit the disease through their feces.
Conclusion:
Ancylostomiasis is a common and easy-to-transmit disease requiring attention from a healthcare provider who can treat the condition with proper drugs. A team of general healthcare physicians and an infectious disease specialist can work together to treat the disease. Therefore, when signs and symptoms are noticed, report to the physician immediately for proper care and management of the condition. However, following safety precautions like walking with protective wear while working in the soil and installing better sewage disposal systems can ultimately prevent the condition, saving us from treatment expenses.
