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51
The subjoined report on tuberculosis " contacts" has been submitted bj
Dr. F. J. Bentley, divisional medical officer.
Report by
Dr. F. J.
Bentley on
" contact "
investigation
Towards the end of 1932 it was thought it might be of interest to ascertain the proportion
of cases of tuberculosis in which there had been known intimate association with a previous case
of the disease. The metropolitan borough medical officers of health and the tuberculosis officers
agreed that such an investigation should be undertaken, and promised their help.
It was arranged that careful enquiry should be made in each new case to be recommended for
residential treatment as to details of contact with previous cases of the disease. It was considered
advisable generally to ascertain contact only within the intimate family circle, and so avoid the
investigation becoming too diffuse. It was proposed, therefore, to concentrate on the following
two categories, which it was thought would yield the most accurate data : (1) where a previously
affected member of the immediate family was alive and suffering from either pulmonary or nonpulmonary
tuberculosis ; and (2) where a death had occurred from pulmonary tuberculosis in
the immediate family within the preceding five years.
It was thought that in the first category there would be no difficulty in ascertaining whether
the tuberculous relative was suffering from pulmonary or non-pulmonary disease, and, if the former,
whether class T.B. plus or minus.
In the second category it was not proposed to sub-divide into positive and negative. It was
realised that association with the disease not falling within either of the above two categories
might also be known; such as, for instance, a definitely known death from non-pulmonary
tuberculosis within the preceding five years, or a death in the family from either pulmonary or
non-pulmonary disease more remote than five years, or a more distant relative or even a lodger
living with the family suffering from tuberculosis who might have been in close association with
the patient. Whilst it was considered difficult to evaluate such association, tuberculosis officers
considering any such of importance were invited to make a note accordingly. Contact otherwise
outside the family circle was not to be specially enquired into, as here again it was considered
advisable not to make the field too wide. Only primary applications for treatment arising
directly from tuberculosis dispensaries have been included.
Information is now available on the first 2,555 cases investigated. Of these, it was noted
that in 1,793 cases there was " no known contact " with a previous case of the disease, leaving
762 cases or approximately 30 per cent, who exhibited contact of some sort.
Details of only 159 surgical cases are as yet to hand, as the period of treatment in such cases
is usually long and the classification is only completed on discharge from residential treatment.
These are therefore excluded. In addition to these, it is proposed to exclude also from
further consideration in the present report 260 female and 232 male pulmonary cases in which
tubercle bacilli had never been demonstrated.
There are thus left 1,904 T.B. plus cases, of which 1,157 were males and 747 were females.
Tables I and II show the details of the findings in males and females, respectively. Where the
relationship of the previous case occurring in the family has not been either that of parent, husband
or wife, child, or brother or sister, they have been grouped together under the term " other
contact." This term, therefore, includes any other intimate contact as mentioned previously
and noted as important by a tuberculosis officer. " Other contacts " have not been sub-divided
as to their clinical classifications.
The frequency with which contact with a previous case is noted, is seen to diminish with
increasing age ; thus, in class T.B. plus cases, whilst 15 per cent, of all males show previous
important contact with the disease in the intimate family circle, the percentage ranges from 22 per
cent, in the 16-20 year group down to 10 per cent, in those over 40 years of age.
As age advances a similar diminution in the importance of contact with a previous case is
seen in females. There is a difference, however, in that the scale in females is generally at a higher
level, as approximately a quarter of all female T.B. plus cases investigated had been in intimate
contact with a previous case of the disease in the family, the percentage showing contact ranging
from 36 per cent, in the 0-15 year group down to 20 per cent, in those over 40 years of age.
It is interesting to speculate on the reasons underlying the greater incidence of contact in
females than in males. One explanation that would appear to be reasonable is that females are
naturally more exposed to infection in the family by reason of their domestic and nursing duties.
Another factor that must have a bearing is that of kissing.
As regards the relationship of what may be called the " infecting " case, it is seen that in
males 58 per cent, were brothers or sisters as against 47 per cent, amongst females, whilst parents
were the " infecting " cases in 17 per cent, of males, as against 30 per cent, in females.
The inverted commas are used because the facts given herewith are not by themselves considered
conclusive of direct infection. Family predisposition, for instance, may be important in
some cases. A tuberculous parent, then, would seem to be a greater danger to a daughter than
to a son, and here again the reason may be the special position of women in the household in regard
to nursing and domestic matters and the like.
It will be seen that 12 per cent, of males and 13 per cent, of females who showed contact
with a previous case in the family were marital contacts.
A previous case of tuberculosis in a child, when dealing with a " new " case in an adult,
immediately raises the suspicion that the primary case was in reality the adult; and it is probable
that the 18 instances in " new " female cases and the 23 instances in males, where a child in the