in August 1961 and, yet. despite the continuing search for vibrios, agglutinable or non-agglutinable, none have been recovered since November of last year. This is not in accordance with past experience of a post-epidemic phase when cases of cholera have continued to appear sporadically for many months thereafter. Whether or not this is related to certain characteristics of the El Tor vibrio is not clear, but experience elsewhere of El Tor as it has occurred during the past months suggests that this is not entirely the answer.
108. The source of the Hong Kong infection was undoubtedly the Kwangtung Province and the introduction was presumably via the boat people who move between Kwangtung Province and Hong Kong in junks and sampans. All of the first cases appeared on the water fronts. and it was only later that cases appeared inland. No case was traced to traffic by rail through Lo Wu where all entering the Colony had been given cholera vaccine or were inoculated on entry,
109. The danger period during 1962 is expected to be during the months of hot humid weather in July and August. Accordingly, a cholera immunization campaign was started in February 1962 and continued throughout March and April. This time, in the absence of an emergency the public response was not so good. However, although only an overall 53% of cover of the whole population resulted, the boat people and waterside dwellers most at risk came forward readily and between 80% and 100% of these groups received a 'booster' dose of cholera vaccine.
110.
An account of the outbreak is not complete without a sincere tribute to the people of Hong Kong. All sections of the community gave unqualified and practical support to all measures taken while the outside world responded immediately and generously to the call for assistance with vaccine when additional supplies were most needed.
References
Wilkinson (1943) Cholera in Hong Kong. Lancet, 1943, Volume (1,
P. 169-170.
White Paper (1961)-A Report on the Outbreak of Cholera in Hong
Kong. Government Printer, Hong Kong.
Pollizter (1959) Cholera-World Health Organization Monograph
Series No. 43.
Phillips et al (1950)–Measurement of Specific Gravities of Whole
Blood and Plasma by Standard Copper Sulphate Solutions- Journ. Biolog. Chem. Vol. 183, No. 1.
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Notifiable Diseases
III. During the year 1961, there was an increase in the number of cases of the more common notifiable diseases, the increase being most marked for measles and chickenpox while there was a decrease in notifications of diphtheria, enteric fever and amoebiasis.
112. Free immunization against smallpox, enteric fevers, diphtheria and cholera continued to be available throughout the year to all members of the public at all Government Hospitals, Clinics, Port Health Inocula- tion Centres and District Health Offices. In addition, inoculation teams visited schools, resettlement estates and other densely populated areas in conjunction with mass immunization campaigns. The outbreak of cholera interrupted for a period of six weeks the special campaigns against diphtheria and for vaccination against smallpox.
13. Towards the end of 1961 and continuing in early 1962, special attention was given to smallpox vaccination and total of 801,876 voc- cinations were performed between November 1961 and January 1962. 114. A summary of the prophylactic immunizations given is at Appendix 6.
Amoebiasis
115. Amoebiasis occurs sporadically throughout the Colony and the number of cases notified varies from year to year. The incidence rate for this infection in 1961 was 6.78 per 100,000 of population being the lowest notified for many years: there were 12 deaths recorded from this
cause.
Bacillary Dysentery
116. There was a marked rise in the number of cases notified with 51.9% of the cases occurring in children under the age of 10 years. Eight deaths were attributed to bacillary dysentery, two less than the number recorded in the previous year.
117. Much intensive health education in the prevention of this infec- tion is carried out by Health Officers amongst those connected with the handling, preparation and sale of food. There were 122 carriers detected amongst case contacts and all were given treatment and not allowed to return to work until three consecutive negative stool specimens had been obtained.
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