FIGURE 1
INCIDENCE OF MAJOR INFECTIOUS DISEASES 1955 - 1969
17} ¢ n thành xa an
CHTCHIL
OTKETCH!
ANGLEONNELL
from Kowloon. No cases appeared on Hong Kong Island. The types of accommodation occupied by the patients included tenement buildings. resettlement estates, junks and wooden huts. All the cases occurred sporadically; there did not appear to be any common relationship or source of infection amongst the cases.
16. The youngest patients were two male children, one aged 4 and the other 8 years. The oldest patients were two males aged 70 and 71 years respectively. The remaining cases, three males and two females, were aged between 25 and 64 years. Apart from the imported case no patient had made a visit to Mainland China prior to his illness. None had had any contact with relatives or friends coming or returning from places outside the Colony.
17. Following the confirmation of the first clinical case of cholera, all the necessary public health measures to contain the spread of the disease were reinforced. The annual inoculation drive, which had been in progress since April, was intensified, particularly in the vicinity of the affected premises and among the population at risk. The contacts of cholera cases were isolated at the Chatham Road Quarantine Centre
6
.
for five full days and were discharged after this period if the stool cultures were negative for V. cholerae for three consecutive days. A Lotal of 338 stool specimens of contacts were examined and among these 22 were found to harbour El Tor vibrios on primary isolation. The carriers were given a course of antibiotic treatment and were discharged from isolation when they had 3 negative stool cultures on consecutive days.
18. The usual bacteriological investigation on the distribution of V. cholerae at patients' homes was carried out and the places commonly found infected were water closets, spittoons and lavatory floors. Routine sampling of nightsoil was carried out throughout the year as part of Hong Kong's anti-cholera surveillance programme. The Grst indication of the possible existence of asymptomatic carriers in the community was a report in the middle of May of the presence of Vibrio choleras El Tor (Inaba) in a specimen collected from a nightsoil route in the western area of Hong Kong Island. This was followed by further positive results scattered almost throughout all nightsoil collection routes in Hong Kong Island. The positive results were traced to the individual pail serving a fat. Residents of the flats and the premises were swabbed, and one asymptomatic carrier, a boy aged 12 years living in the Western District, was found. He was treated at Sai Ying Pun Hospital until his stool was negative for V. cholerae. In Kowloon and New Territories there were, bowever, no positive isolates from routine nightsoil samples before the occurrence of cholera vases.
19. Following the report of the first case of cholera in Kowloon on 5th July the tempo of nightsoil sampling was stepped up. Samplings from dry pail public latrines, flush type public latrines, dry pails in licensed food premises, nightsoil labourers, illegal immigrants and remand prisoners were done. Samples were taken from toilets in trains coming from Lu Wu on the Sino-British frontier. None of these produced positive results.
20. Throughout the course of the outbreak the public was kept fully informed of the progress of events. Health advice with regard to preven- tion of cholera was given to the public through the press, radio and television, and other forms of publicity such as posters, handbills, health education exhibitions, health talks and film shows, etc., were used as fully as possible.
21. Hong Kong was last declared free from cholera infection on 27tb October. 1969. Since then no further case of the disease has been
7
Page