Wednesday, January 26, 2011

Sarcoptes scabiei, a Manifest of a Parasitic Relationship

Relative Species:
- Homo sapiens
- Sarcoptes scabiei
Sarcoptes scabiei utilizes the upperdermis of humans to produce eggs and to travel from host to host. Parasite species is located globally with no specific interest in race, socioeconomic class, and climate. Reported cases are estimated at at least 300 million annualy [1]. Symptoms of infection involve an extreme itchy feeling that produces rashes and sores.

Sarcoptes scabiei and Host Description:
- This parasite is responsible for an infection known as scabies. This tiny mite’s name is derived from scabere, the Latin word meaning to scratch [2]. Sarcoptes scabiei is an ectoparasite in which humans serve as the only host [3].

Life Cycle:
- Sarcoptes scabiei possess a relative simple life cycle compared to most parasites[1]. These mites wander on the surface of your skin to find a suitable place to burrow into. Once the females are in place they release eggs, generally 2-3 which hatch in approximately 4 days. Upon hatching, a larva emerges which will become a nymph after several moltings. Continuous moltings lead to the adult form [2].

- This parasite causes an infection, but not necessarily a disease. Recall that an infection is basically the body’s initial reaction to the pathogen. In this case, inflammation of the epidermis as a result of prolonged scratching is the main symptom of Sarcoptes scabiei.

An Example of True Parasitism:
- Up through current lectures in parasitology, we are slowly approaching a clearer definition of a parasite. A parasite usually benefits from it's host, while the host is left at a disadvantage. The parasite, upon successfully establishing a foothold in the host, has not only shelter and nutrients, but most importantly a place to reproduce and to pass beneficial genes to the next generation. The debilitated host, in the case of harmful parasites, now has to cope with the infection. If an individual with a case of scabies is infected, the parasite obtains a place to disperse offspring as well as the potential to travel via human skin to skin contact.
Future Questions and Observations:
-Upon describing this parasite, one might wonder why this parasite is harmful if it doesn't for the most part actually penetrate and live inside the body. What must be taken into consideration is the location that the parasite utilizes. Eventhough only our upperdermis is affected, humans depend on the the integumentary system especially the skin as our first line of defense against pathogens. When the skin is utilized by this species, the skin is left in a reduced state thus making the host more suspectable to other foreign invaders. Superficially, no pun intended, their is no harm done, but what happens to the female mite upon death? Does it simply just blow away and the skin fills in the hole like modern Departments of Transportation fill in holes on the highway, or does the carcus become a nest to other microorganisms?

-Perhaps another question that can be addressed is why humans are the only organism in which this host can infect.


  1. you are invited to follow my blog

  2. Maybe humans are the only ones with sparse enough hair growth to make the living easy.

  3. The video link doesn't work.

    Going to your ending statement about what happens to the dead organisms, I would imagine that the dead carcass of these parasites would both either just fly away as dead skin does and also aid in infection. These parasites are spread through just a touch, meaning they don't have a great method of sticking to their hosts. Once they are dead, the carcasses have the same property and might possibly be carried away in the wind like dead skin. Just the act of rubbing skin on something could rid the body of the dead organism. Also, mentioned in the blog, these parasites leave the skin prone to infections and other skin disorders. The dead carcasses can be also one of the reasons other than the live parasites as to why the skin is so open to skin infections. As these carcasses disintegrate, the enzymes associated with this can possibly irritate the skin furthermore and provide another avenue for infections.

  4. After reading the blog, I was thinking that maybe the carcass stays on the skin and it could contribute to the body's immune system going down, which might be a benefit to the parasite's babies.

    Also, how does one come in contact with these mites? Does the skin have to have an open sore or pore to allow the mite to attach on?

    Stephanie mentioned that "they don't have a great method of sticking to their hosts" since they can travel from one host to another just by skin contact. It makes me think that if one of these mites got onto a person that the mite would just wash off when you took a shower. So does this mean that they actually do have a good method of sticking to the host?