The Source of Scabies

Scabies (Sarcoptes scabiei) are a type of microscopic parasitic mite found throughout the world. Scabies infect humans and other animals, such as pigs, cats and dogs, in which scabies can cause mange. According to the CDC, scabies are arthropods (insects with hard skeletons) in the class Arachnida, so they have eight legs.

Mobility

• Scabies can crawl, but they cannot jump or fly. The only way they can infect people is by crawling directly onto their skin. According to Urology Channel, scabies crawl slowly, about an inch a minute. Transfer of the mite from one person or animal to another usually requires prolonged contact to allow the mite time to transfer.

Person-to-Person

• Transmission of the scabies variety that infects humans most commonly involves skin-to-skin contact, such as occurs when people sleep together, engage in sexual intercourse or live in very close proximity and touch each other. Thus, outbreaks are common in nursery schools where children play together and in nursing facilities where staff members inadvertently carry mites from one person to another.

Animal-to-Person

• Scabies on an infected animal can also crawl onto a person and infect the skin, often causing a generalized rash and severe itching, but the animal varieties are not able to multiply on humans, so the infection subsides as the mites die. However, if the animal isn't treated with a scabicide to kill the mites, the person, especially a child playing with an infected pet, can become reinfected over and over again.

Belongings-to-Person

• Scabies mites feed on the skin but, according to the CD, can live for up to 3 days off of the human body, so they can survive on belongings, such as clothes, bed linens, brushes or towels long enough to wait for another human to touch the item and allow the mites access to the skin again.

Reproduction

• Once on the skin, scabies use suckers on their front legs to hold onto the skin. Their mouths and cutting parts of their legs burrow into the outer layer of the skin, causing severe itching, irritation and rash. As they tunnel into the skin, the females lay eggs that hatch into larvae that then crawl into hair follicles to mature. The CDC states that females can lay up to three eggs per day and survive for one to two months. Eggs hatch and mature into adults within about two weeks, but only about 10 percent survive to become adult mites. However, this number is sufficient to continue the infection.

Considerations

• Prompt treatment with scabicides, such as permethrin or lindane, can prevent scabies from spreading, but all clothes and linens must be washed in hot water or dry-cleaned and furniture and carpets vacuumed to prevent reinfection.