It affects all races and social classes world-wide. The interval between the end of one epidemic to the beginning of another is about 10-15 years. Scabies may occur in any age but it is most common in children and young adults. The overall sex incidence is equal. Overcrowding associated with poverty and poor hygiene in under-developed countries encourages the spread of scabies.
Transmission is by close physical contact like sharing of a bed.
Studies have demonstrated that indirect spread by clothing and bedding is not important. Although scabies is common in school-age children, transmission in schools is unlikely. Outbreaks occur in hospitals, old-age homes and other institutions. Outside the host, free adult mite and eggs can survive 36 hours and 10 days respectively. Clinical Features Symptom occurs 3 to 4 weeks after the acquire of the infection.