Epidemiology of Infectious Diseases: Scabies
Causal agent
A parasitic infestation of the skin caused by Sarcoptes scabiei, a mite.
Common clinical features
- Rash: involved skin becomes itchy, irritated, warm, reddened and blistered.
- Skin irritation is more likely to be seen in the webbing between the fingers and toes, in the folds of the elbow, armpit, belt-line, abdomen, groin and in the genital area.
- Small children or infants may have involvement of the face, scalp, palms of the hands or soles of the feet.
Epidemiology
- Worldwide.
- More prevalent in children and young adults, in urban areas and in winter1.
- In the UK scabies has increased since 1991 and there have been reports of outbreaks in nursing and residential homes and hospitals.
Reservoir
Humans
Mode of transmission
Direct, prolonged skin-to-skin or close bodily contact.
Infestation may also occur by contact with infested clothing, bedding etc.
Incubation period
2-4 weeks, and 1-4 days for persons previously exposed.
Period of Communicability
Until treated.
Once away from the human body, mites do not survive more than 48-72 hours.
Prevention and control
Two treatments 1 week apart for cases. Contacts should have one treatment at the same time as second treatment of the case1.
Children may return to school as soon as properly treated. Treatment should include the entire household. If lesions can reliably be kept covered, or skin to skin contact avoided, exclusion may be shortened1.
References
Further Resources
The Guidance on Infection Control in Schools and Nurseries. Available at: http://www.hpa.org.uk/infections/topics_az/schools/schools_guidelines_2006.pdf
© CM Kirwan 2006