In the last century the itch caused by scabies was named "7 year itch.
" In the past physicians deduced that there was a 7-30 day period between scabies outbreaks.
It was later learned that this does not hold true during periods of war, where scabies epidemics are more common.
A 20 year study showed that generally one out of 31 people exposed to scabies have a chance of infestation.
Infestations are higher in winter than summer months.
Mites are thought to survive longer away from the body in cooler temperatures.
As well there tends to be more crowding of people during winter months.
Mites may also be susceptible to chemicals in human sweat.
It has been estimated that approximately 5% of the world's population was infested with scabies at the end of the 20th century.
This accounts for three million cases.
Children are more frequently infested with scabies.
Ethnic differences are thought to be due to overcrowding, housing, socioeconomic and behavioural factors.
Poverty, poor nutritional status, homelessness, dementia and poor hygiene increase risk of scabies infestation.
Doctors and nurses appear to be more prone to scabies infestations.
Scabies outbreaks typically occur in hospitals, nursing homes, prisons or kindergartens.
Scabies generally spreads from one person to the next.
Commonly close contact is the classic mode of spread of scabies between individuals.
Although scabies can be acquired from clothing, bed linen or furniture, this is not felt to be a common means of spread.
Infestations by the crusted or Norwegian scabies variety may occur more frequently from non human contact, such as contact with bed linen or furniture.
This species of scabies sheds thousands of mites daily.
Intra family spread is common.
The mite may also be spread by sexual contact.
There are medications available to eliminate scabies infestations.
These can be obtained by prescription from a physician.