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50
Secondary Infection.
Relation to Disinfection.
Considered under Disinfection.
Relation to Removal of Primary Infecting Case.
In previous reports, particularly those for the years of heavy
scarlet fever incidence when many cases were treated at home, it
was shown that removal to hospital of the infectious case does not
play a great part in limiting infection; or conversely, that retention
at home of an infectious case does not result in a high incidence of
disease. The following table which gives the percentage of
secondary cases, return cases and home-treated cases as a factor
of the total number of cases notified in the year shows that there
is no constant relation between the proportion of cases treated
at home and the extent of secondary infection.
Home-
Percentage of Treated
Secondary Cases Return Cases Cases.
1927 12.6 0.4 18
1928 10.0 3.0 63
1929 17.4 4.0 62
1930 12.0 3.8 58
1931 13.5 3.1 25
1932 13.0 3.3 16
1933 15.3 4.1 38
In considering the effect of hospitalization in preventing
secondary infection, one must take account not of the date of
removal of the primary case, but the date of notification which can
be accepted as being that of the date of diagnosis. It is apparent
that if there is delay in removing the primary case owing to limited
accommodation, some secondary infections might occur which
would have been prevented had immediate removal been possible.
On the other hand, the occurrence of those secondary infections
through failure for any reason to diagnose the infecting case
would not be lessened by the most ample hospital provision.
37 secondary cases occurred before the primary cases were
diagnosed and therefore were not attributable to shortage of
hospital accommodation. A further 27 secondary cases occurred
in spite of immediate removal to hospital of the primary case.
Of the remainder, in only 4 cases did the onset of the illness of the
secondary case occur later than the 8th day from the onset of the
illness of the primary case.