scabies mite

SCABIES MITEBy : Amal Mohamed and Sahro Elmi

INTRODUCTION Scabies is a contagious

ectoparasite skin condition caused by the mite Sarcoptes scabiei.

It effects people of all classes and ethnicities all over the world. 

It is also known as the human itch mite or the scabies itch mite.

More than 300 million cases occur worldwide every year

HISTORY: Scabies is an ancient affliction, estimated to

have infected humans for the last 2,500 years. 

The first recorded reference to scabies is believed to be from the Bible.

The Roman philosopher Aristotle reported on “lice” that would “escape from little pimples if they are pricked” in the fourth century BCE scholars believe this was actually a reference to scabies. The Roman physician Celsus who is credited with designating the term “scabies” to the disease and describing its characteristic features.

TAXONOMY Kingdom- Animalia Phylum- Arthropoda Class- Arachnida Order- Acarina Family- Sarcoptidae Genus- Sarcoptes Species- scabiei

HOST Definitive Host:

Humans (host specific)

Intermediate Host: none

Dogs and cats are infected by different types of mites. Scabies that affects dogs are called mange.

Egg: Oval ,0.10 to 0.15mm Larvae : 3 legs and lasts 3 to 4 days Nymph: 4 legs Adult: round, sack-like eyeless mite,

Female (0.30 to 0.45mm long and 0.25 to 0.35 mm wide) and Males are half the size of the females. Malting takes once and female are fertile for the rest of her life(1-2 months)

MORPHOLOGY

LIFE CYCLE

THE LIFE CYCLE IN WORDS Female deposit 2-3 eggs per day burrow under

skin. After the eggs hatch, the larvae migrate to the skin surface and burrow into the intact stratum corneum to construct almost invisible, short burrows called molting pouches. The larvae molt and resulting nymphs and molting into adults. Impregnated females leave their molting pouches and wander on the surface of the skin until they find a suitable site for a permanent burrow. While on the skin’s surface , mites hold onto the skin using sucker-like pulwilli attached to the two most anterior pairs of legs. When the impregnated female mite finds a suitable location, it begins characteristic serpentine borrow , laying eggs in the process. Under the most favorable of conditions about 10 percent of the eggs give rise to adult mite.

TRANSMISSION Occurs primarily by the transfer of the

impregnated females during person-to-person, skin-to-skin contact.

Scabies can also be transmitted through contact with the bedding or clothing or infected persons and mites can survive up to 24 hours outside the skin.

SYMPTOMS The most common symptoms

of scabies is itching and skin rash, all caused by sensitization (a type of “allergic” reaction) to the proteins.

feces of the parasite and can be find at the following places of the body:

Between the fingers Wrist Elbow Armpit Nipple Waist Buttocks Shoulder blades

SYMPTOMS Crusty or scaly skin which is called

crusted (Norwegian) scabies (more severe). Affects the elderly, immunocompromised or persons who have conditions that prevent them from itching and scratching.

DIAGNOSIS Examination of skin for mite burrows Skin scraping to look for mites or eggs

under the microscope

TREAMENT The current treatment of choice is the

topical use of permethrin cream (5%).  Crotamiton and ivermectin are

alternative drugs.  Ivermectin is effective for treating

crusted scabies in immunocompromised person.

No vaccine

nna

CONTROL Don’t share personal items such as

combs, clothes, towels, bedding Change clothing regularly � Wash bedding regularly �

VIDEO http://animal.discovery.com/videos/mon

sters-inside-me-scabies-mites-and-the-itch.html

REVIEW How is it transmitted between humans? How is it diagnosed? What is the treatment? What is one control method?

REFERENCES http://www.stanford.edu/group/parasites

/ParaSites2009/LeighaWinters_Scabies/LeighaWinters_Scabies.htm

http://www.cdc.gov/parasites/scabies/prevent.html

http://animal.discovery.com/videos/monsters-inside-me-scabies-mites-and-the-itch.html