Ancylostoma duodenale is a worm that belongs to the phylum Nematoda (round worms). They are widely distributed throughout the world, specifically in the so-called underdeveloped countries where sanitary conditions favor their prevalence..
It was adequately described by the Italian doctor Angelo Dubini in 1843. It is considered the causal agent of a disease known as Hookworm, which affects humans, generating symptoms mainly in the digestive system..
Hookworm is a fairly common disease in the tropics. If it is not treated, it can have serious consequences derived from anemia caused by parasites that feed on the host's blood..
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Ancylostoma duodenale is a multicellular eukaryotic organism. This means that they have their genetic material enclosed in an organelle called the cell nucleus, which is delimited by the nuclear membrane. That genetic material (DNA) is packaged in such a way that it makes up chromosomes.
It is a multicellular organism because it is made up of tissues, which are made up of different types of cells that fulfill various functions, such as contraction, nutrition and reproduction..
Likewise, this belongs to the group of animals that are triblastic, since during their embryonic development they present the three germ layers: ectoderm, endoderm and mesoderm. The cells that make up these three layers undergo a differentiation process to transform into the various tissues that will make up the adult animal.
Like all nematodes, Ancylostoma duodenale it is a deuterostomized animal, which means that when it is developing, from a structure called blastopore, the anus is formed and the mouth is formed secondarily elsewhere.
In addition, this parasite is pseudocoelomed, since they have an internal cavity known as a pseudocoelom that does not originate from the mesoderm..
These parasites reproduce in a sexual way, they are oviparous, because they reproduce by means of eggs and present an indirect development, since they must go through several larval stages until they become adults..
They are hematophagous parasites, because in order to survive they need to be inside a host feeding on their blood. They are also pathogens because they are considered to be the cause of a disease called hookworm.
The taxonomic classification of Ancylostoma duodenale is the next:
-Domain: Eukarya
-Animalia Kingdom
-Phylum: Nematoda
-Class: Secernentea
-Order: Strongiloidae
-Family: Ancylostomatidae
-Gender: Ancylostoma
-Species: Ancylostoma duodenale.
Ancylostoma duodenale It is a short cylindrical worm. His body is strong and resistant in appearance and build. The extremity that corresponds to the head is called cephalic and the opposite, caudal. They have a whitish or gray color, although when it has sucked blood from the host, it acquires a warm pink color.
At the cephalic end there is a widening known as the buccal capsule. In this you can see two pairs of teeth or fangs, through which it is fixed and embedded in the walls of the intestine of its host.
They present sexual dimorphism, since there are certain morphological aspects that allow differentiating male from female specimens. Females are longer than males. They can measure up to 2 cm and their body ends in a cone shape..
The males, on the contrary, measure up to 1 cm and their body ends up expanding in what is known as the copulatory bag. It also has a kind of hooks known as copulating spicules. These have an elongated shape and serve during the copulatory process.
Humans are the main host of this parasite, so part of its life cycle takes place indoors and the rest outdoors..
The eggs are expelled through the feces to the external environment. Here, depending on the environmental conditions, the egg can hatch releasing a type of larva that is known as rhabditiform (L1).
There, under different environmental conditions, either inside the feces or on the ground, this larva undergoes several molts and becomes filariform larvae (L3), which constitutes the infecting form of the parasite..
The filariform larvae can survive, as long as the environmental conditions (temperature, humidity) are favorable, waiting for a human host to appear to infect.
When they come into contact with a human being, the larvae have the ability to penetrate the skin and attach themselves to the circulatory system to be transported through the bloodstream. In this way they manage to reach the lungs and begin an upward path through the airways towards the pharynx, in order to be swallowed..
Already inside the digestive system it reaches the intestine, which is its place of residence within the human being. Here the larvae continue to undergo metamorphosis until they reach adulthood..
The adult parasite attaches to the wall of the intestine and feeds on the blood of its host. It remains there laying eggs that are expelled through the feces.
The disease that produces Ancylostoma duodenale It is known as Hookworm. This can be transmitted through two mechanisms.
First of all, the most common and frequent way in which this parasite is transmitted is to walk barefoot on contaminated ground, in which there are infecting larvae (microfilariae).
The second, less frequent form of contamination is through ingestion of food contaminated with the larvae. Hence the importance of maintaining good hygiene when preparing meals..
The symptoms and signs of hookworm will depend on the organ of the body that is affected by the parasite or its larvae. As is known, during its life cycle, the larvae of this parasite pass through various organs.
Well, their transit is not innocuous, but they cause damage as they pass. These damages are generally minor. However, they can also become very severe, especially when the infection becomes chronic..
At the level of the skin, the condition is caused by the damage caused by the larvae when they pierce it to enter the host's body. In this sense, the most common symptoms and signs are:
- Erosions
- Erythema (Redness)
- Pruritus (Itching).
- Appearance of papules
- Ulcers
Because the intestine is where the adult forms of parasites settle, the digestive system is one of the most symptomatic ones. These include:
- Diarrhea.
- Sickness.
- Vomiting.
- Increased amount of gas and flatulence.
- Lack of appetite.
- Feeling of abdominal discomfort.
When the larvae are in the lung and during their transit through the airways, they can cause injuries and discomfort, such as:
- Small hemorrhages.
- Inflammation of the pharynx.
- In some cases with bloody expectoration.
- Irritation at the level of the larynx, which interferes with the emission of the voice.
- Appearance of heart murmur.
- EKG with abnormal results.
- Abnormal enlargement of the heart.
Other symptoms that may occur as a result of infection by Ancylostoma duodenale They are:
- Anemia, due to the loss of blood product of its absorption by parasites.
- Weakness and tiredness, caused by anemia.
- Fainting.
- Possible seizures of epilepsy.
- Pallor.
Diagnosis of infection by Ancylostoma duodenale it is mainly based on the identification of eggs in the feces of the infected person. However, complementary studies such as the determination of anemia and eosinophilia can also help to make a definitive diagnosis..
The doctor may go to perform a blood test, which specifies the leukocyte count. A person who is undergoing an infection by this parasite, will present an increase in his number of eosinophils.
These are the blood cells that are responsible for fighting parasites. Likewise, it is also possible to show a decrease in hemoglobin, which leads to think about a possible anemia.
However, the definitive diagnosis of hookworm is given by the determination of the existence of eggs in the feces of the affected person..
For the stool examination, what is done is to take a sample of the patient's stool. The most widely used method is the so-called "Willis method", which consists of mixing the sample with a saturated sodium chloride solution..
This test is based on the differences in density between different materials. What happens here is that the eggs, as they are less dense, tend to float and adhere to a slide..
By looking under a microscope, the doctor is able to identify the eggs of Ancylostoma duodenale.
Hookworm disease is a disease in which treatment must be approached from different sides, in order to eradicate both the infection and its consequences.
As you might expect, the first thing your doctor does is prescribe an anthelmintic medication. The most commonly prescribed drug is albendazole. If this is not prescribed, they may prescribe mebendazole. Both have the function of eliminating adult parasites and their larvae, through different mechanisms.
Likewise, the doctor may also prescribe some iron supplements, in order to correct the underlying anemia in the clinical picture. You can also make some dietary recommendations in which the amount of protein that the person eats is increased.
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