reported. The disease, however, continues to be prevalent in nearby countries. Anti-cholera surveillance measures are, therefore, continued in force and strict quarantine restrictions are maintained in respect of neighbouring countries declared infected.
Amoebiasis
22. This disease continued to occur endemically, being most prevalent in the overcrowded urban areas. A total of 85 cases were notified. The disease remained predominantly one of adult males.
Bacillary Dysentery
23. This disease showed a slight decline in incidence after a rise in three successive years. The disease occurs at all ages, but 33.7% of the notifications were in respect of children under the age of 5 years. Shigella flexneri and Shigella sonnei remained the predominant organisms isolated.
24. Transmission of infection among families and in institutions is a feature of the disease and very often a number of symptomless carriers are detected among members of the same family or inmates of the same institution. In all a total of 247 carriers were discovered during investigations of reported cases. All were given appropriate treatment.
25. In February 1970 an outbreak of bacillary dysentery occurred in an orphanage home in Tai Po, New Territories. Between 24th February and 2nd March a total of 7 cases aged between 6 months and 2 years were reported. Extensive investigations in the institution were carried out and some 70 inmates in the institution, including predominantly children and some adults, were found at one time or the other to be carriers of the disease. The responsible organism was predominantly Shigella sonnei. Samples of water taken from the water laps and water storage tanks showed the presence of faecal organisms. The source of water supply to the home was traced to a hill stream. on the upper course of which there were a number of inhabitants living nearby. Among the inhabitants one girl aged 3 years was found to be a carrier of Shigella sonnei organisms. Water samples taken from the stream also showed the presence of Shigella sonnei and faecal organisms. The primary cause of the outbreak was presumably due to a water-borne spread from the contaminated source of water supply, but the subsequent secondary spread in the home must to some extent be due to cross transmission among the inmates, as Shigella sonnei
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organisms were also detected from swabs taken from bedding, col frames, and mattresses in the nursery.
26. Following the occurrence of the outbreak all necessary im- mediate control measures to contain the spread of the disease were employed. All cases and carriers were sent to Lai Chi Kok Hospital for treatment. Thorough disinfection and chlorination of the water supply in the home was carried out. Appropriate action was also taken at the source of water supply to prevent further contamination. The home undertook to apply to the Water Authority for a mains water supply to the institution, as a permanent measure to prevent further outbreaks.
Chickenpox
27. This is a very common disease among children, almost all the cases reported being under 15 years of age. The seasonal prevalence of the disease is in winter and spring, and hence the earlier part of the year saw an increase in the number of notificatious.
Diphtheria
28. As a result of annual immunization drives, which have been in progress since 1959, the incidence of the disease has shown a continuous and steady decline, falling from 73.0 per 100.000 population in 1959 to 1.6 in 1969. The disease affects largely children, and 74.2% of the cases were under the age of 10 years. The case fatality ratio in 1969 was 16.1%, and death occurred primarily among the unimmunized children. Corynebacterium diphtheria mitis remained the predominant organism isolated in clinical cases.
29. A total of 13 carriers was discovered among contacts of reported cases. Each was treated and, if necessary, isolated until proved free of infection.
Enteric Fever
30. Typhoid fever showed a slight increase in incidence during the summer months. The disease in Hong Kong is generally mild, and the case fatality ratio is less than 2%. Transmission of infection is frequently associated with neglect in personal and food hygiene. As elsewhere the peak incidence occurred in children of school age and young adolescents. Free inoculation was offered and the usual preven. tive measure enforced, with special attention to environmental and food hygiene and the control of food premises.
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