Cholera
53. Cholera has not been reported in Hong Kong since October 1969. Routine sampling of nightsoil for cholera vibrio was carried out on a year-round basis as part of the surveillance programme. In June, cholera vibrio were isolated from a sample of nightsoil taken routinely from a collection route at Shau Kei Wan on Hong Kong Island. In July, cholera organisms were again isolated from the same nightsoil route, but in each case subsequent samples from the same route were negative. In September, specimens taken from nightsoil vehicles serving the Happy Valley and Wan Chai areas were found to be positive, but subsequent investigations from these two sources proved negative. No case of cholera was reported during the period when positive nightsoil samples were obtained. The public were informed of the findings and advised to observe strictly the rules of personal and food hygiene.
54. No mass immunization campaign was carried out during the year, but emphasis was placed on the importance of personal, environ- mental and food hygiene as safegurards, both against cholera and the other intestinal groups of communicable diseases. Strict quarantine restrictions were maintained in respect of countries declared infected.
Amoebiasis
55. This disease continued to occur endemically, being most prev- alent in overcrowded urban areas. A total of 35 cases was notified. The disease remained predominantly one affecting adult men.
Bacillary Dysentery
56. This disease showed a further decline in incidence, falling from 543 cases in 1971 to 462 cases in 1972. It affected all ages, but 27.3 per cent of the notifications concerned children under five. Shigella dex- neri and Shigella sonnei remained the predominant organisms isolated.
57. Transmission of infection among families and in institutions is a feature of the disease, and as in the past, a few symptomless carriers were detected among members of the same family, or immales of the same institution. In all, a total of 167 carriers was discovered during investigations of reported cases during the year. All were given appropriate treatment.
Chickenpox
$8. This is generally a common disease among children. During the period under review, a total of 510 cases was notified, almost all
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being under 15. The seasonal prevalence of the disease being in the winter and spring, the earlier part of the year saw an increase in the number of notifications.
Diphtheria
59. Only five cases of the disease were notified during the year, an even lower figure than the 25 cases recorded in 1971. As a result of annual immunization drives since 1959, the disease bas shown a con- tinuous and steady decline, falling from 2,087 cases in 1959 to five cases in 1972.
Enteric Fever
60. The number of cases notified was 438, a decrease of 77 cases over the preceding year. The disease was generally mild, and the case fatality rate was less than one per cent. Transmission of infection was frequently associated with neglect in personal and food hygiene. As elsewhere in the world, the peak incidence occurred among children of school age and young adolescents. Free inoculation was offered. and the usual preventive measures enforced, with special attention to environmental and food hygiene, and the control of food premises.
Malaria
61. The incidence of malaria during recent years has fallen con- siderably. Of the 10 cases recorded in 1972, one was considered to be an induced infection, while ninc were imported.
Measles
62. A total of 783 notifications of the disease was reported during the year. As shown in Figure 4. the incidence of measles in Hong Kong has in previous years tended to fall into a distinct biennial pattern, with exacerbation of the disease every alternate winter and spring. Since December 1967, measles vaccine has been available reg- ularly at all government maternal and child bealth centres, and during campaign periods, the vaccine has also been made available, through mobile teams, to children living in resettlement and housing estates, tenement buildings, and other crowded areas. Since the last epidemic in 1966-67, the discase incidence and its mortality have remained low. These results were due, at least in part, to the availability throughout the year of free vaccine for immunization, and continuing health education to encourage parents to seek early medical advice.
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