What is Hookworm?

Hookworms are parasitic roundworms that feed on blood in the intestine and cause helminthiasis infections. Hookworm infection can be found all around the world, but it is especially prevalent in places with limited access to clean water, sanitation, and hygiene. 


Taxonomy of Hookworm

  • The hookworms belong to the kingdom Animalia.

  • The hookworm phylum is Nematoda.

  • The class of hookworm is Chromadorea.

  • The order of hookworm is Rhabditida.

  • The family is Ancylostomatidae.

  • The genus of hookworm name is Ancylostoma.

  • There are two common types of hookworm names that affect humans. The Hookworm scientific name of the two common species is Ancylostoma duodenale and Necator americanus.


Characteristics of Hookworm Species

Ancylostoma Duodenale

  • Ancylostoma duodenale is a tiny, greyish-white worm with a cylindrical shape.

  • The buccal capsule features two ventral plates on the anterior border.

  • They each have two big teeth that are joined at the base. A pair of tiny teeth can be detected in the buccal capsule's depths.

  • Males are 8–11 mm long and have a copulatory bursa on the back. Females measure 10–13 mm in length, with the vulva at the back.

  • Females can deposit anywhere between 10,000 and 30,000 eggs per day.

  • A female Ancylostoma duodenale has an average lifespan of one year.


Necator Americanus

  • Around the front border of the buccal capsule, Necator americanus contains two dorsal and two ventral cutting plates.

  • It also possesses a pair of subdorsal and sub ventral teeth near the back of the mouth.

  • Males average 7–9 mm in length, while females average 9–11 mm.

  • These parasites have a 3–5 year life cycle on average.

  • They can lay anything from 5,000 to 10,000 eggs per day.


Hookworm Life Cycle 


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  • The hookworm life cycle starts with larvae, not the hookworm eggs. These larvae infect the host, and the most common route of infection is through the skin.

  • To hatch, hookworm larvae require warm, moist soil at a temperature above 18°C. If they are exposed to direct sunlight or become dried out, they will perish. Ancylostoma larvae can withstand higher temperatures than Necator larvae. 

  • First-stage larvae are non-infectious, and once hatched in the deposited excrement, they feed on it before moulting into second-stage larvae, which feed on soil microorganisms. 

  • The rhabditiform stage is occupied by first and second stage larvae. They will moult into third-stage larvae known as the filariform stage, which is the non-feeding, infective stage, after feeding for around seven days.

  • Filariform larvae have a two-week lifespan. They are highly mobile and will seek higher ground in order to increase their chances of finding a host.

  • The larvae of Necator americanus can only infect through entering the skin, however, Ancylostoma duodenale can infect orally.

  • The skin of barefoot walkers is a common route of passage for the larvae. The larvae enter the host's circulatory system and proceed to the lungs, where they exit the venules and enter the alveoli.

  • They are coughed up, ingested, and end up in the small intestine after travelling up the trachea. The larvae moult into stage four, the adult worm, in the small intestine. From penetration to maturity in the intestine, it takes around five to nine weeks.

  • Necator americanus can infect people for one to five years, with many worms dying in the first year or two. Some worms, on the other hand, have been known to live for fifteen years or longer.

  • Ancyclostoma duodenale worms, on the other hand, are only alive for around six months. Larvae, on the other hand, might lie latent in tissue storage for years before being recruited to replace dying worms.

  • The worms mate inside the host, where the females also lay their eggs, which are then released into the environment via the host's excrement, restarting the cycle.

  • Ancyclostoma duodenale can produce between twenty-five and thirty thousand eggs each day, while Necator americanus can lay between nine and ten thousand. The two species' eggs are indistinguishable.

  • Because worms take five to seven weeks to mature, symptoms of infection can occur before eggs are identified in the stool, making hookworm illness difficult to diagnose.


Habitat of Hookworms

  • Southern Europe, North Africa, India, China, Southeast Asia, some parts of the United States, the Caribbean, and South America are all home to Ancylostoma duodenale.

  • The Ancylostoma duodenale hookworm is well-known in mines due to the consistent temperature and humidity, which creates a perfect environment for egg and juvenile development.

  • Hookworms infect an estimated 1 billion individuals worldwide. Ancylostoma duodenale is transmitted through skin contact with larvae-infested soil.

  • Necator americanus can be found predominantly in tropical and temperate climates. Because the eggs must hatch in a damp, warm, and shaded habitat, this parasite thrives in warmer regions.

  • In freezing conditions or with soil desiccation, the eggs and juveniles of Necator americanus species die due to their thin, smooth shells. As a result, the type of soil in which the parasite lives is crucial to their perfect living conditions.

  • Ideal soil conditions are found in places where water drains at a consistent rate and soil particle sizes are neither too large nor too small.

  • The Necator americanus can then burrow to the surface and attach to the skin of their next victim due to the degree of wetness and holes in the soil.

  • The strong rains and warm temperatures that characterise tropical settings appear to be compatible with high transmission rates.

  • One peculiarity of Necator americanus is that it tends to prefer male hosts over female hosts, which is most likely due to labour division in areas where it thrives.


Diagnosis, Prevention and Treatment from Hookworms

  • The signs and symptoms of hookworm infection differ depending on the hookworm species and the host.

  • Itching and a rash on the skin are the earliest signs of infection in humans. Light infections may cause no symptoms, while heavy infections can cause abdominal pain, diarrhoea, loss of appetite, weight loss, exhaustion, and anaemia in people. Physical and cognitive development in children may be harmed.

  • Dermatitis, enteritis, and intestinal blood loss are all possible in dogs and cats. Anaemia, hemorrhagic diarrhoea, anorexia, and dehydration are all possible in dogs.

  • Cattle may develop skin sores, anaemia, and lose weight quickly.

  • Abdominal pain, loss of appetite, and geophagy are all symptoms of a light hookworm infection.

  • Severe protein deficit or iron deficiency anaemia might result after a heavy infection. Iron deficiency anaemia can cause mental dullness and heart failure, whereas protein deficiency can cause dry skin, edoema, and abdominal distension from edoema (potbelly).

  • This parasite can infect the foetus in pregnant women, resulting in problems such as low birth weight, maternal anaemia, and infant death.

  • Fecal examination to discover hookworm eggs confirms the diagnosis for many types of hookworm infections. Fecal flotation is used to detect hookworm eggs in animals.

  • It's impossible to tell the difference between Ancylostoma duodenale and Necator americanus eggs. Larvae can only be found in stool specimens that have been left at room temperature for at least a day.

  • The importance of education, improved sanitation, and controlled disposal of human excrement cannot be overstated. In endemic locations, wearing shoes can also help to decrease the spread of infection.

  • Treatment for hookworm infections varies depending on the hookworm species and the diseased host species. Antihelminthic drugs such as albendazole and mebendazole are used to treat worms in humans. 

  • A range of anthelmintics can be used to treat animals. 

  • Supplemental iron, a high-protein diet, or a blood transfusion may be required in severe cases of anaemia.

  • Albendazole, mebendazole, and benzimidazoles can all be used to treat Ancylostoma duodenale. Pyrantel pamoate is a different option.


Conclusion

Hookworms are parasitic worms that feed on other animals. Hookworms are parasitic worms that live in our lungs, skin, and small intestine. Hookworms are transmitted to humans through hookworm larvae found in the faeces-contaminated ground. Hookworm infections affect an estimated 576 to 740 million individuals worldwide, according to the Centers for Disease Control and Prevention. Poor sanitation primarily affects populations in poorer countries in the tropics and subtropics. These infections are caused by parasitic hookworms. Necator americanus and Ancylostoma duodenale are the two most common hookworms that cause illness. The aim of hookworm treatment is to get rid of the parasites, increase nutrition, and treat anaemia consequences.

FAQs on Hookworm

1. What are Hookworms?

Ans: Hookworms are parasitic roundworms that feed on blood in the intestine and cause helminthiasis infections. Hookworm infection can be found all around the world, but it is especially prevalent in places with limited access to clean water, sanitation, and hygiene. Ancylostoma duodenale and Necator americanus are the two main hookworm species that infect humans.

2. How Hookworms Spread in our Body?

Ans: Hookworm eggs are passed in an infected person's faeces. Eggs are deposited on the soil when an infected person defecates outside near bushes, in a garden, or a field, or when an infected person's faeces are used as fertiliser. They can then mature and hatch, resulting in the release of larvae (immature worms). The larvae develop into a form that can penetrate human skin. Hookworm infection is spread mostly through barefoot walking in polluted soil. Ingestion of larvae of one type of hookworm (Ancylostoma duodenale) can also transmit the disease.

3. What are Hookworm Signs and Symptoms?

Ans: The initial signs of infection are frequently itching and a localised rash. When the larvae penetrate the skin, these symptoms appear. A person with a mild infection may not show any signs or symptoms at all. Abdominal pain, diarrhoea, loss of appetite, weight loss, exhaustion, and anaemia are all symptoms of a severe illness. Children's physical and cognitive development may be harmed.

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