Etude de la gale option europeene bio

I causal agent Sarcoptesscabiei is a microscopic, parasitic mite which infests the cutaneous layers of humans and animals. Sarcoptesscabiei is better known by its common name, scabies or « la gale ». It’s most popularly transmitted via human-to-human contact. People with weakened immune systems are more likely to contract scabies as well.The grown-up female is 0,4 mm long, the male 0,1 in 0,2 mm.The parasite is little visible in the naked eye, he is grey. He has no neck and he is provided with 4 pairs of legs, allowing his movement on the skin.

Life cycleAfter fertilization, the female digs(accentuates) a hole where it deposits its eggs. She lays 40 in 50 eggs during her life(which lasts 4 in 6 weeks)Eggs are hatching (éclosion) after 3 or 4 days, and go out of the furrow ,are transformed into nymphs and then into grown-up parasites in 10 days. The grown-up sarcopte survives only 24 at 36 hours out of his host while eggs live at least 10 days. Acarid female is responsible for the mange. The male dies after fertilization of the female.

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II Epidemiology and risk factors

Contrary to popular belief scabies cannot be transmitted via animal-to-human contact. It’s just human to human. Overall, scabies has been infecting the world for over 3,000 years and continues to persist. It affects people of all races and social classes.

 Scabies is a worldwide disease but is endemic in impoverished areas (under development country). The transmission by direct human contact is the most frequent, favored by closeness, so mange being a sexually transmitted disease.

 The infested, but not symptomatic subjects are contagious in incubation time. Because of the limited but possible survival of the parasite outside his host, some cases can be owed to an indirect contamination by the bedding, the clothes, or other objects in touch with the infected people. Many do not even realize they have scabies until 4-6 weeks after infection. Thus, infected persons may successfully infect many others before they even notice their own symptoms.

DISEASE

Symptoms do not appear for up to two months after being infested.  

The most common symptoms of scabies, itching and a skin rash, are caused by sensitization (a type of “allergic” reaction) to the proteins and feces of the parasite. Severe itching, especially at night, is the earliest and most common symptom of scabies. Itching and rash may affect much of the body or be limited to common sites such as:

• Between the fingers
• Wrist
• Elbow
• Armpit
• Penis
• Nipple
• Waist
• Buttocks
• Shoulderblades

Diagnosis:

During a consultation, the doctor has to search the specific signs of the scabies. Whenever possible, the diagnosis of scabies should be confirmed by identifying with a microscope the mite or mite eggs or fecal matter (scybala). However, a person can still be infested even if mites, eggs, or fecal matter cannot be found.