Risk Factors of a Scabies Infestation and The Causes
The scabies affliction is caused by the Sarcoptes scabiei mites. Those mites are attracted to the human smell and warmth. After the infestation, the females dig small threadlike tunnels called burrows and lay eggs inside. Those burrows can sometimes be seen.
Scabies spreads this way:
- * A close physical contact is needed for the scabies to be transmitted because they cannot jump or fly and they move very slowly.
- * Scabies mites can be transmitted through personal items, clothes, bed sheets or towels because the mites can survive up to 4 days without a human host.
- * The scabies mites prefer wrinkled areas of the skin like elbows, knees or wrists because they can burrow quicker into the deeper layers of the skin. The spreading to different parts of the body can be made through scratching and touching.
- * A female mite will deposit 10 to 25 eggs in her burrows before she dies. The incubation period is of 3 days, after which the larvae hatch and reach for the superficial layers of the skin. It takes 14 to 17 days until the larvae become mature and start reproducing. This cycle continues until they are eradicated.
The mites that live on humans cannot survive on animals the other way around: the mites that infest animals are not able to survive or reproduce on human hosts. They can however live for a few days on a different type of host and cause temporary symptoms like itch or bumps.
The periods of incubation and contagiousness
Scabies is a contagious affliction. The mites can be transmitted to other persons before and after the symptoms appear for as long as the infestation is untreated. In the case of a first scabies infestation, the person is contagious but will not reveal signs for several weeks. This is known as the incubation period.
In the case of a re-infestation, it will only take a few days until the symptoms will show.
A higher risk of exposure to scabies mites is presented by the next groups of people:
- * Persons that live or work in institutions such as nursing homes, homes for the developmentally disabled, asylums and prisons.
- * Sexually active adults. Close skin-to-skin contact (not necessary sexual intercourse) makes transmission of the scabies mites easier.
- * Children from developing countries.
- * Persons that live in crowded conditions.
Severe cases of scabies like crusted scabies are likely to occur among persons unable to communicate their physical problems and persons with impaired immune system, such as HIV positive persons.