Published online by Cambridge University Press: 15 May 2009
The incidence of positive toxoplasmin skin test among subnormals in hospital was compared with that in subnormals attending day training centres and among normal children taken into County Council children's homes. Twelve out of 120 subnormals below the age of 20 attending day training centres were positive to the test, and 23 were positive out of 233 subnormals of the same age tested in hospital.
There was only 1 positive out of 71 children under the age of 18 in the County Council children's homes, compared with 29 out of 296 subnormals of this age who were tested.
The incidence of positive skin test among 115 mongols under the age of 50 was about 11% in each age range, whereas that in 709 other subnormals rose from 5% in those below the age of 10 to 30% in those over the age of 30.
Although factors similar to those causing admission of normal children to County Council care often determine the admission of subnormals to hospital, the children in County Council homes did not share the high incidence of infection which was found in subnormals.
It is suggested that the majority of infections among subnormal children are postnatally acquired. Since the incidence was the same in subnormals living at home as among those in hospital it is suggested that some personal habit commoner among subnormal than among normal children exposes the subnormals to an increased risk of infection.