carriers detected amongst case contacts and all were given treatment and not allowed to return to work until three consecutive stool speci- mens had been obtained. The common organisms isolated were $. flex- neri and S. sonnei.
Chickenpox
101. A widespread outbreak of chickenpox occurred during the first quarter of 1963 with the incidence peak occurring in March. The total number of cases notified during the year was 707 as against 498 in 1961. The mortality remained low, there being 5 deaths recorded as against 7 deaths in the previous year.
102. The intensive immunization against diphtheria which com- menced in the autumn of 1959 was interrupted for the second year in succession by an anti-cholera vaccination campaign. The incidence of diphtheria, however, continued to decline, a total of 1,023 cases being notified during the year as compared with 1,334 in 1961, 1,450 in 1960 and 2,087 in 1959 when the number of cases notified was the highest recorded in any year. Over 75% of the cases in 1962 were in children under the age of 10 years, with more than 50% occurring under the age of five. There were 154 carriers detected amongst the case contacts as compared with 95 in 1961 and 35 in 1960. All carriers were isolated in hospital until they were proved free of infection.
103. The case fatality rate for diphtheria, which had been showing a continuing decline in recent years, rose from 82% in 1961 to 10% in 1962.
104. C. diphtheriae mitis continued to be the predominant causative organism and only in rare instances was an 'intermedius' or 'gravis' strain isolated.
Enteric Fever
105 . A total of 826 cases was notified compared with 742 in 1961 and again the peak of the incidence was in July. The number of deaths due to enteric fever was 21 compared with 24 in the previous year giving a case fatality rate of 2.5% as against 3.2% in 1961. Twenty-eight car- riers were detected as against 26 in 1961 and all were treated and ren- dered negative. Facilities for inoculation remained freely available to the public and the annual campaign was maintained in schools. Food hand- lers and the stuff of licensed restaurants, eating houses and water boats are required by law to submit to inoculation with TAB annually.
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Malaria
106. There were 794 cases notified of which 434 or 54.6% were re- corded in the Sai Kung District of the New Territories.
Measles
107. The incidence of measles remained low, after the extensive epidemic in the winter and spring of 1960-61, until September, 1962 when the increase in notifications heralded the start of another major epidemic. The number of deaths, mainly due to broncho-pneumonia, remained high, reflecting the incomplete notification of this disease. There were 2,317 cases notified with 326 deaths.
Tuberculosis
108. Tuberculosis remains the major public health problem in Hong Kong. The control programme has so far shown results mainly in the prevention of tuberculosis amongst children and in the reduction of mortality at all ages. The problem is considered in detail in paragraphs 124 to 180 below.
Poliomyelitis
109. There were 363 cases of paralytic poliomyelitis noúfied during the year which is the highest incidence recorded since 1948. During July of peak of 78 cases occurred followed by a gradual decline, with 12 cases being reported in November. Thereafter there was again a sharp increase with 27 cases occurring in December and 35 during January, This was contrary to all previous experience as these are normally the months of lowest incidence.
110. During the summer months, as in past years. Type I poliovirus was predominant but in November, December and January, Type II and Type III were the predominant strains isolated. It appeared that the epidemiological pattern was changing.
111. A mass vaccination campaign, using a Sabin trivalent oral vaccine, had been planned to take place in two phases in January and March 1963. The first phase in the urban areas covered ten days from 2nd to 11th January, and oral vaccine was given to children in the age group most at risk, namely those aged between 6 months and 5 years. The campaign in the New Territories was extended to the 31st March to cover the small and more isolated village communities, the aim being to 'seed' the virus in each group within as short a time as possible. After the first phase, the incidence of paralytic disease declined sharply
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