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16
REPORT ON THE EPIDEMIOLOGY OF POLIOMYELITIS
IN EALING DURING 1947.
The outbreak of poliomyelitis which occurred in the Borough
during the Summer and Autumn of 1947 followed closely the
general trend of the disease notified in similar areas on the periphery
of the Metropolis and indeed of the total notifications for the
country as a whole. Examination of the epidemiology of the
disease has been made for comparison with other areas and to
illustrate some peculiarities in the local spread of the outbreak.
The Borough of Ealing extends to an acreage of 18,739 lying
on rising ground to the North of the Thames. Predominantly
residential, the Borough has a population of 185,000 and extends
from the more industrialised areas of Acton and Willesden to the
East to the more rural districts of Middlesex to the West. Situated
so near London, on the main road and rail communications to
the West, there is considerable free movement of people to and
from the metropolis, and considerable North to South traffic by
road skirting London to and from the bridges at Chiswick and
Kew.
General Epidemiological Findings.
The outbreak in Ealing may be considered as commencing
duiing the last week in July, reaching its maximum incidence
during August and early September and then gradually declining
to the end of the year. Prior to this period three cases of poliomyelitis
had been notified during the Spring of 1947 but in none
of these cases was the diagnosis confirmed, and they reflect the
growing awareness by the local practitioners of the probable
arrival of poliomyelitis.
The weekly notifications are as shown in the Chart I. As
these individuals were with one exception admitted to hospital
for further investigation and treatment it has been possible to
determine those cases in which the diagnosis was subsequently
confirmed. A total of 70 cases were notified in the Borough, of
which 47 were found to be definite cases of poliomyelitis or polioencephalitis.
The chart of weekly notifications conforms closely with that
of a simple epidemic, there being an explosive outbreak rapidly
attaining its maximum and then gradually declining during subsequent
months. There is no significant variation in the trend of
the weekly notifications to indicate that the outbreak was in anyway
modified by important factors during the course of the outbreak
although the whole picture may well have been affected by
factors operating during the whole period, or initiated at the
commencement,