were immunized in June and 23% in July. Thereafter the response decreas- ed rapidly and only another 6.0% were immunized in the period August- December, giving a total immunity state of 77.0%
79. With the early appearance of the disease and its unprecedented continuance into the winter months, a re-inoculation campaign was commenced in mid-November and continued to the end of December. This campaign resulted in 10.9% of the population being given booster doses. The relationship of immunization, incidence and severity are discussed later in this report.
80. A total of 1,890 persons, immediate contacts of the clinical cases, were isolated; most were detained until seven consecutive and negative rectal swabs had been obtained. However, amongst these were 106 symptomless carriers; these were treated by oral streptomycin and not discharged until after both three consecutive and negative rectal swabs had resulted and a period of isolation of not less than seven days had elapsed.
81. The home of each case was thoroughly disinfected after bacte- riological swabs had been taken from all sites which might possibly give epidemiological clues; positive results were obtained from a variety of places but no definitely significant pattern emerged. Investigation of food habits revealed little of assistance. and widespread sampling of foodstuffs, including fish, shell-fish and water, were consistently negative, cxcept on one occasion when the body contents of a spotted crab, taken from heavily-polluted water, were found to contain cholera vibrios. Subsequent extensive sampling of various types of crustacea were consistently negative. However, the possibility of transmission of the disease by contaminated shellfish cannot be ruled out and further investigations are proceeding.
82. Apart from the fatalities, all cases responded rapidly to treatment. The age and sex distribution is shown in Table 7.
From this it will be seen that almost half the cases occurred in persons aged 45 and over, a group which constitutes only 17.4% of the population. In the 20-44 age-group, the incidence approximates to representation in the population while the younger age-groups had a far smaller expe- rience than would be expected.
53. Table & shows the relationship of inoculation state to the severity of the disease. The figures emphasise the abnormal mildness of the out- break-many of the patients in the 'mild' category had few symptoms and were only diagnosed as cholera after routine bacteriological in- vestigations. There is also some indication that the vaccine had afforded some degree of protection.
TABLE J
CHOLERA CASES BY SEVERITY AND INOCULATION STATE ¿Figures in brackets represent percentage of total cases)
No. inoculated... No. not inoculated
Total
Males
Mid
1916.5%)
Moderate
Severe
605.20
40 3.5%)
29/25.20
18:15.7%
39033.99%
Toral
29(25.230 86074.80)
48(41.70
24(20.90 43037.4%) 11501000
TABLE 9
SEVERITY OF CHOLERA CASES BY AGE, SEX AND INOCULATION STATE (Figures in Brackets Show Percentage of Total Cases)
**་
Mild
0-44
Moderate
Severe
0-44
45+
0-44
45!
TABLE 7
ارم
Fears
5-9 Years
CHOLERA¦ AGE AND SEX INCIDENCE, 1963
10-19 20-44 45-59 60- Years Years
Totul
Years
Years
F A
F
M F
M F M F
M
2 4 1
6
T
34 15 16 12
M F
16 10 66 49
% of total
5.21
2.61
11.3
33.9
24.3
21.6
99.92
of age-group
in population 15.3
13.7
18.8
14.8
12.3
5.1
100
LB
Inoculated 97.80 201701 1(0.9% 10.9% 201.770 0(0%) Not inoculated 10(8.7%) 7(6.170) 21.7%) 5(5.2%) (0(8.7%) 1613.9%)
Femaley
Inoculated 504.3%) 3(2.6%) Notinoculated 6(5.2%) 6(5.2)
217%) 2(1.7%) 20.7% 0:0% 6(3.2%) 43.5% 6(5,270) 76.170
84. Table 9 shows the severity of cases related to age, sex and inocula- tion state. The numbers in each category are too small to enable significant conclusions to be drawn, but there is, as would be expected, a definite tendency for the disease to be of a more serious nature in the elderly. There is little of note in the sex incidence-43% of the cases occurred in females who represent 49% of the population. The table again em- phasises the apparent value of inoculation, particularly the fact that
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