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Secretary for Health, Welfare and Food: The rodents were not infected and there was no sign of disease. So all these findings are part and partial of environmental contamination, because it could have infected anyone who was in physical contact with some of these environmental samplings. So they were just passive, mechanical carriers.
I would like now to go to the possible explanation for the outbreak. I would like to reassure the public that there is no evidence to suggest that the disease is transmitted by the waterborne route, or by infected dust aerosols because we have done tests to show that. And it is not, so-called, airborne, as the public might perceive. This is clear from our epidemiological picture and the laboratory results. Given the unique distribution pattern of infected Block E residents and taking into account the contact with SARS patients and the large number of patients reported with diarrhoea symptoms, environmental factors played a major role in this outbreak. So you see that the very unique pattern of distribution and the large number of patients affected with diarrhoea symptoms. Environmental factor must be a major part of this outbreak. The studies also show that many patients with SARS, excrete coronavirus in stool. So, this is based on a lot of studies now that we know that patients with SARS not only with its virus present in the droplets and respiratory secretions and is also present in many body fluids and in particular present in the stools of patients with SARS. And where the SARS could survive for periods, the define periods, we cannot have any knowledge but certainly the studies initially done in the University of Hong Kong demonstrates the SARS virus can survive in faecal samples. Many patients in the Amoy Gardens outbreak had diarrhoea contributing to a significant virus load being discharged into the sewer system in Block E. So it is not just one patient because the patient, in fact, a number of individuals in Block E who also had diarrhoea. So, it led to quite a large amount of virus being present in sewage system.
It is probable that the index patient initially infected a relatively small group of residents within Block E and subsequently the rest of the residents within that block through the sewerage system, person-to-person contact and the use of shared community facilities such as lifts and staircases. These residents subsequently transmitted the disease to others, both within and outside Block E through person-to-person contact and environmental contamination. So we have a sequence of events. The patient initially infecting a small number of individuals in Block E, who then infected the rest of the residents and the rest of the community in Amoy Gardens. And we believe the main source of infection is the excreta in the sewerage system.
The bathroom floor drains, the dried-up U-traps provide a pathway through which residents came into contact with droplets containing virus from the contaminated sewage. So the U-shape prevents the reflux if it's not filled, then you can get these droplets going back into the flats. When the bathroom was in use, with the door closed and the exhaust fan switched on, there could be negative pressure to extract contaminated droplets into the bathroom. So, you can see that if you have exhaust fans which withdraw air from within the pipes, you then create a system where the droplets would be facilitated to go into the bathrooms. Contaminated droplets could then have been deposited on various surfaces such as floor mats, towels, toiletries and other bathroom equipment. So, you have this effect of drawing droplets into the bathroom. Water vapour generated in the shower and the moist conditions of the bathroom could also have facilitated the formation of water droplets. The chance of exposure was increased given that the bathrooms in the units in Amoy Gardens were generally very small. They are only about 3.5 square metres.
We believe there could also be secondary cases of transmission through close contacts with cases. So there is a whole series of methods of infection. One is through the sewage -- through droplets, the second is through person-to-person contacts, and the third is through environmental contamination. So there were three routes of infection giving rise to this outbreak in Amoy Gardens.
Just to summarise the actions the Government took to tackle the situation. We conducted disinfection and thorough cleansing with the co-operation of the owners and the residents. Particular attention was paid to the sinks, bathrooms, bathtubs, wash basins, toilet bowls, floor drains in the bathrooms and kitchens and the water storage tanks were cleansed. Subsequent tests for E. Coli showed that disinfection of the drain pipes was effective. So we took a whole series of actions. We insured that these were sterilised and cleaned, met our standards before the residents were allowed back in.
The Food and Environmental Hygiene Department gave advice to residents on how to disinfect their flats as a precautionary measure, teaching them all the things they should do. The residents were also advised to keep sufficient water in the U-traps of drainage outlets to ensure proper functioning. Remember the U-traps, we believe, are a very key part of the whole process and of course this is something that we also want you to inform the public of because these U-traps are in all our flats and they should be filled with water.
To minimise the likelihood of similar outbreaks in future, we have produced a guide to educate the public on cleansing and disinfection of households, including bathroom cleansing, ensuring the proper functioning of the water seal and U-traps. So this is what we talked about U-traps and that is why they are so important because the U-traps prevent the reflux and also prevent any cockroaches from climbing the drainage back into the flat. If the U-traps are filled, then the sewage does not go back into the flats and the cockroaches also do not go back into the flats. So it is very simple device.
Improvements to environmental hygiene will be made and pest control will be stepped up on a territory-wide basis.
The management company is carrying out a comprehensive inspection of the drainage system of the blocks within the development. We have also published a set of guidelines to draw the attention of the public to proper maintenance and repair of the drainage system and sanitary fixtures. The guidelines are available from the Buildings Department website and have been distributed to all management companies and owners' corporations.
The buildings management authorities of buildings where confirmed SARS patients reside have been notified of the infections and are required to take proper disinfection measures. Because of the knowledge now on how infection spread within a block of households, now that once we have a case of SARS notified, we then inform building management of what they should do to prevent any possible transmission within that building. That's why every time that we are isolating an individual, we advise the building management and the names of the buildings are on the web. So people know what action has been taken and who should take appropriate action.
The Food and Environmental Hygiene Department (FEHD) will inspect buildings to see they meet required standards. Major cleansing and disinfection procedures were also conducted in Lower Ngau Tau Kok Estate, Telford Gardens and the surrounding areas, by building management working with the FEHD. We also want to emphasize that the infections that we see in Lower Ngau Tau Kok, Telford Gardens and Lee Kee Building were all related to the Amoy Gardens outbreak because of their geographical vicinity and there were a lot of people movements between Amoy Gardens and these estates. In our investigations, we found that many residents in Amoy Gardens had relatives in some of the other estates, particularly in Lower Ngau Tau Kok, because some of the families and some of the individuals in Amoy Gardens, when there was an outbreak of the disease, in fact moved back to Lower Ngau Tau Kok. So we believe that the infections in these surrounding areas were due to people movements and the environmental contamination in Amoy Gardens where some of the residents in adjoining districts visited as well. So when you look at the whole control of Amoy Gardens, the rest of Amoy Gardens and the peripheral districts was an event that occurred subsequent to the outbreak in Block E.
(Chinese portion)
I also want to just highlight that in fact there was some concern about Koway Court that the same case was happening. I just want to say that this morning in fact the Chief Executive and I went to Koway Court to look into the investigations that were going on there. And obviously the CE was very concerned that we do not have another outbreak similar to that of Amoy Gardens. We will assure him that it would not occur because the environment ecology is very different. We had looked at the orientation and the number of people affected. Obviously the number affected is fortunately very small. This time we have learned from the lesson from Amoy Gardens. We took very quick action. We took very quick action because the team from Department of Health and the Food, Environment and Hygiene Department and all the other government departments worked very closely and very well to really make sure that the infections did not spread in that community. We did not find any evidence of sewage leakage or any of the problems that we saw in the Amoy Gardens. So the situation is different. If we now see two cases in one building, we want to make sure that there could not be any potential outbreak in any building.
(Please also refer to the Chinese portion)
End/Thursday, April 17, 2003
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