Sarcoptes scabiei It is an animal that belongs to the phylum of arthropods, specifically to the family Sarcoptidae. It is characterized by its globose body and by having very small, almost atrophied legs..
This species was described for the first time by the Swedish biologist Charles De Geer in 1778. Currently it is known that within this species there are some varieties, about 8 approximately. Each variety parasitizes a specific mammal.
This is a mite that is parasitic in life. Its main host is humans and it is responsible for a pathology known as scabies, whose main symptom is intense itching..
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Sarcoptes scabiei it is a mite that, as a member of the Eukarya domain, is made up of eukaryotic cells. Inside these, the DNA is properly packaged in the nucleus, forming the chromosomes. They are multicellular because they are made up of different types of cells.
They are tripoblastic and coelomed. This has to do with its embryonic development. During this period the presence of three germ layers becomes evident: endoderm, mesoderm and ectoderm. These are important because from them the different organs and structures that will make up the adult individual are formed..
In addition, they have an internal cavity called a coelom. They have bilateral symmetry, which means that their body is made up of two exactly equal halves, joined in the longitudinal plane..
They are dioecious, which implies that the sexes are separate. They reproduce sexually, with internal fertilization and indirect development.
Likewise, they are of parasitic habits, specifically they are ectoparasites. This means that in order to survive, they must be attached to the body surface of their host..
Finally, there are different varieties of Sarcoptes scabiei, whose classification depends on the animal they use as a host. This is how it is Sarcoptes scabiei var hominis, that affects man; Sarcoptes scabiei var bovis, that affects bovines; Y Sarcoptes scabiei var cuniculi, that attacks rabbits, among others.
The taxonomic classification of Sarcoptes scabiei is the next:
Sarcoptes scabiei it is an extremely small parasite, the adult individuals of which are between 0.3 and 0.5 mm in length. As in many species of animals, females tend to be larger than males..
The body is globose in appearance and is made up of two areas or zones: gnatosome and idiosome. On its dorsal surface you can see elements such as spines, transverse grooves, bristles and scales.
The gnatosome corresponds to what would be the head. There you can see the so-called chelicerae, which are pincer-shaped appendages that are provided with teeth.
On the other hand, the idiosome is the largest portion of the animal's body. From this emerge the legs, which are organized in four pairs. Two pairs are oriented towards the anterior region and the other two towards the posterior part.
It is important to mention that the front legs are much more developed than the back ones. Females present suckers on pairs of legs 1 and 2, while males present them on pairs 1, 2 and 4.
Likewise, there are also differences regarding the location of the genital pore. In the case of males, it is located behind pair 4 of legs, while in females it is located between pairs of legs 2 and 3.
Due to the fact that this mite presents an indirect development, throughout its life cycle it presents several stages, which are: egg, larva, nymph and, finally, adult individual.
The entire biological cycle occurs in its only host, the human being. As it is known, this is a parasite that is deposited in the layers of the skin, so it is there, specifically, where it wreaks havoc.
Their reproduction is sexual, so a copulation process is required to occur between the female and the male. Once this happens, fertilization occurs. Importantly, this process occurs on the host's skin surface..
After this, the female begins her transfer towards the interior of the skin layers, specifically towards the horny layer. Throughout the course, it creates tunnels and also spawns, that is, it leaves its eggs. Leaves an average of 3 eggs per day.
The incubation period for these is between 3 and 8 days. The female dies inside the tunnels dug by her, approximately 5 weeks after fertilization. The male dies much earlier, immediately after fertilization.
After the incubation time, the eggs hatch and larvae hatch from them and begin to move towards the surface of the skin. During their journey, they form small tunnels that are known as larval bags. They remain in this larval form for approximately 3 days..
Inside the larval pouches, the larvae molt and transform into nymphs, which are small and subsequently undergo another molt to become larger nymphs. Its appearance is similar to that of adult mites, but much smaller..
Finally a last molt occurs and then the adult individual emerges. These are located mainly on the host's wrists and fingers, to whose surface they remain fixed thanks to the presence of suction cups that they have on their back legs..
Sarcoptes scabiei it is the causative agent of a disease called scabies. Colloquially, this disease is also known as scabies.
It is a rather annoying pathology, characterized by skin lesions and a lot of itching. It is widely distributed throughout the planet, but it is especially abundant in places with poor hygiene and in places where people are overcrowded..
Scabies is spread through direct contact between an infected person and a healthy person. This is because the parasite is found on the skin surface.
Generally, the most frequent form of contagion is through sexual intercourse or sleeping together, since in these activities skin-to-skin contact is prolonged, allowing the transfer of the mite.
Likewise, contagion is possible, although to a lesser extent, when sharing personal items such as towels, clothing and sheets..
There are places where the outbreak of scabies can occur, because there are many people there who are in constant contact. These are schools, nurseries, nursing homes and even prisons.
Scabies is a pathology that has quite characteristic symptoms. Symptoms that occur include:
The time that elapses between infection and presentation of symptoms is approximately six weeks.
Generally the diagnosis is based on the observation of the clinical manifestations of infection by Sarcoptes scabiei. The doctor can observe the presence of skin lesions made by the parasite and its larvae as it travels through the layers of the skin. Likewise, the simultaneous presence of itching helps to guide the diagnosis..
However, to be more sure, there are specialists who prefer to take a skin sample by scraping it. This sample is observed under the microscope and thus the infection can be confirmed, identifying eggs, larvae, nymphs and even adult mites in said sample..
Sometimes the doctor can even remove the mites from superficial skin lesions.
Treatment for scabies is based on the total eradication of the mite. Both the infected person and those who live with him should undergo treatment equally, even if they do not show any symptoms..
The most commonly used medications are permethrin, lindane, benzyl benzoate, chromatiton, and sulfur with petroleum jelly. These are topical medications that must be placed, not only on the lesions, but also on the entire body surface from the neck down.
Likewise, the treatment also includes prophylaxis with all the affected clothes. In this sense, clothes and sheets should be washed at a temperature of approximately 60 ° C. After that, they must also be dried at high temperatures, in order to eradicate parasites, eggs or larvae that may be found there..
If all of the affected person's clothes cannot be washed, then it is important to keep them away from the patient and anyone else for 72 hours. In this way, if there are any parasites there, they will die, since they cannot survive more than 3 days without being in contact with a host..
Again, this should apply to everyone living with the person infected with Sarcoptes scabiei.
Because the transmission of Sarcoptes scabiei is based on direct contact between people, as well as on the use of personal implements, preventive measures are oriented towards this.
First of all, the first thing to avoid is sharing clothing, towels, and sheets with other people, especially if someone is known to be infected with this mite..
Likewise, if someone you know has been diagnosed with scabies, it is important to avoid direct skin-to-skin contact with this person. It is also important to wash all clothes in water that is hot enough so that you can kill the parasite..
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