in a marked decrease in diphtheria in those sections which have been completed. However, even in such areas, complete control of the disease has not yet been achieved owing to internal movements of population and to the apathy shown by certain sections of the community towards the immunization facilities offered.
Enteric Fever
80. During 1960, there was no marked increase in the incidence during the summer months and the numbers of notifications received showed a fall of twenty three per cent compared to 1959. A close epidemiological study of typhoid fever is now being made and pre- liminary results indicate the possibility that water from polluted sources does not play such an important role in the dissemination of the disease as had been supposed previously.
81. Owing to the priority given to diphtheria immunization through- out the year, no intensive prophylactic drive against enteric fever was possible. However, facilities for inoculation remained freely available to the public and the annual campaign was maintained in schools, as the highest incidence recorded during the past few years has been con- sistently in the 10-14 age group,
Malaria
82. The number of cases of malaria notified increased markedly following a widespread survey undertaken in the New Territories; the survey is described later in this report. There were no deaths from malaria reported.
Measles
83. With over 100,000 births occurring each year, measles is wide- spread in the Colony. It is a disease of the cooler months, from November to March and, as elsewhere, recurs in two-year cycles, An epidemic, occurring in the winter and spring of 1960-61, was the most extensive recorded in recent years and caused a large number of deaths which were mainly due to intercurrent bronchopneumonia. Measles ranks second only to tuberculosis as a cause of death from infectious disease.
Poliomyelitis
84. A small seasonal rise during the summer months accounted for the increased incidence of cases of poliomyelitis recorded during 1960,
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but the case fatality rate fell to 15.5 per cent compared with 23.2 per cent in 1959. The attack rate was 4.96 per 100,000 of population.
85. A polio-virus laboratory was established carly in the year by the Government Institute of Pathology in co-operation with the Department of Pathology in the University of Hong Kong. Two surveys were under- taken to determine the prevalence of poliomyelitis in the Colony. The first survey was designed to provide information on the prevalence of excretors of the virus; faccal specimens from healthy children under the age of 5 years were collected in a number of clinics and child health centres and despatched to the laboratory for culture. Table 4 presents the findings.
TABLE 4
TYPES OF POLJOVIRUS FOUND AND EXCRETOR BATE
No. of specimens examinegi
438
Poliovirus positive
Total
Type 1 Type 2 Type 3 positive
Excretor rate
pher 1,000 20.5
$6. The second survey was a serological survey designed to assess again, after 3 years, the immunological status of the Chinese population of Hong Kong. Samples of blood were collected at various hospitals, clinics and maternal and child centres throughout the urban areas of the Colony, mainly from healthy children between the ages of 7 months and 9 years; none of the persons from whom the samples were collected had received immunization against poliomyelitis. The prevalence of poliomyelitis antibodies in the samples was then determined and the results are detailed in Table 5.
TABLE S
DISTRIBUTION OF POLLOMYELITIS ANTIBODIES IN DIFFERENT AGE-GROUPS
Nomméres Weddih antibodies no poliovirus Cyper
nwo types Tovar Type Type Type
I&ITAJ JAJ
No. of
JENT
427)
Mor, vel
ONE ODE
Ja
1-12 məmla
145
124 months
151
Type Type Typ
83096.90 42 10 44029.20 H
Tradel
Wonde
3
2
57099.00 2
2
20 1.49
17
23-36 mont
179
18010.1) 20
24
12
37-8 months
130
X 5.1
7 SB(38.4) L 57031.80 15 15010.91 3
*
$704.0
134, 7.90
17
19 6104.0
41024.0
49-60 months
11:2
LC 0.9)
6
I
3
14070
LIC 9.80 * 2.10
12 10
* 13
9 1027.7) 69001,6)
9 2819.3) 1307.91
5-9 par
1444
t E #532.60 7DELA
Figures in parentheses demode percentage of total sera examined in each are-moụp.
87. From the results of the two surveys it is apparent that there is wide circulation of the three types of poliomyelitis virus amongst the child population, that by the age of 5 years over 99% of children bave
21
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