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The Secretary for Health, Welfare and Food, Dr Yeoh Eng-kiong, today (February 28) strongly refuted the allegation that he had attempted to halt investigation into rats or had covered up the role of rats in the transmission of SARS (Severe Acute Respiratory Syndrome) in the Amoy Gardens outbreak.
He also denied that he had said anything to the effect that the residents of Amoy Gardens would have to be sacrificed.
"In fact, the actions taken attest to the contrary and that the Government actively investigated the role of rats in the outbreak.
"My guiding principle at all times is that public health, and the health of every member of the community must be paramount in every Government decision relating to the SARS outbreak," Dr Yeoh said.
Dr Yeoh will testify before the Select Committee at a public hearing to be held in March. However, in view of the seriousness of the allegations, a spokesman for the Health, Welfare and Food Bureau said it is necessary to present the following facts which demonstrate that the allegations are totally groundless:
*Dr Stephen Ng was introduced to the Government on April 3, 2003 as someone who had training in the field of epidemiology and who wished to assist in the investigation of the outbreak.
*Dr Yeoh made arrangements for representatives from various Government departments to meet Dr Ng to exchange views on the SARS outbreak, and the Amoy Gardens outbreak in particular. Dr Ng subsequently participated in two meetings, the first being held in the afternoon of April 4 and the second in the morning of April 5.
*Dr Ng was not employed or commissioned by the Government in any capacity during the SARS outbreak. He was not engaged as a consultant of the Government. He did not participate in the field investigation of the Amoy Gardens outbreak in association with Government departments.
*At the invitation of Dr Yeoh, Dr Stephen Ng attended a meeting in the morning of April 5 with representatives from Government departments to exchange views on the epidemiological investigations carried out by the Government.
*Other than the epidemic curve information, the meeting also noted that initial test results for rat droppings collected by Food and Environmental Hygiene (FEHD) had shown positive Polymerase Chain Reaction (PCR) results for coronavirus in some of the samples. As there had already been earlier reports of domestic cats kept by residents being tested positive for coronavirus but with the subsequent evidence pointing to cats being carriers rather than the cause, the meeting recognised that the positive PCR results in the rat droppings could have been due to a number of factors, including environmental contamination.
*As autopsies would show changes in the rats if they had been infected, Dr Yeoh instructed an expert from Agriculture, Fisheries and Conservation Department (AFCD) to carry out autopsies on rats trapped in Amoy Gardens immediately. The preliminary results produced on the same day (a public holiday) indicated no changes indicative of a severe respiratory virus infection in the rats. Moreover, the PCR results of the swabs and tissues taken from these autopsied rats were all later found to be negative.
*In order to further clarify the precise role, if any, played by rats in the Amoy Gardens outbreak, Dr Yeoh instructed in the meeting that investigations on rats should be intensified with additional tests (including autopsies) to be carried out on more rat specimens. The Government Virus Unit also carried out additional PCR tests on tissue samples and antibody tests on the blood samples from rats trapped in Amoy Gardens. The reports of these serological tests also did not show evidence of SARS coronavirus infection in the rats.
*A pest control expert from FEHD who attended the meeting gave an account of the pest control measures in the Amoy Gardens area. He observed that rat infestation did not appear to be a problem in Amoy Gardens and there were few signs of rats. He further explained that obvious signs of rat infestation had not been detected in the common areas of Block E, including the rooftop, staircases, light wells, utility rooms, as well as pipes on walls. Dr Yeoh instructed FEHD to intensify their pest control efforts in Amoy Gardens and the surrounding areas. He also asked FEHD to collect more specimens and to extend the collection area to beyond Amoy Gardens, such as Lower Ngau Tau Kok Estate and Telford Gardens.
*At the meeting, there was no discussion on the evacuation of all the residents of Amoy Gardens because evidence at that time, and even in retrospect, did not provide a basis for any further evacuation plan other than the removal of Block E residents. The latter had already been carried out on April 1, 2003.
Dr Ng subsequently published a hypothesis that roof rats were the culprits responsible for the transmission of the SARS coronavirus in the Amoy Gardens outbreak. However, the hypothesis did not tally with the findings of the field investigation by FEHD. The following are the details of the Government's investigation findings:
*FEHD found that rat infestation in Amoy Gardens was not serious, and that sewer rats, rather than roof rats, was the more common species in Amoy Gardens.
*Between April 2 and May 30 last year, approximately 100 traps were set everyday (equivalent to some 4,500 trap-days) in various parts of Amoy Gardens, including residential blocks and the common areas, only a total of 14 rats were trapped. No dead rat was found at Amoy Gardens during the period, and, indeed, no rat was trapped after April 11. Of the 14 rats trapped in Amoy Gardens, only one belonged to the roof rat category.
*Further, positive PCR results were all traced to sewer rats, not roof rats. The finding that rat infestation was not serious was consistent with the information as reported by the management of Amoy Gardens.
*The DH and its multi-disciplinary team (which included WHO experts) had also carried out extensive investigation on the Amoy Gardens outbreak. Six of the 62 specimen samples of the rats tested by PCR were positive but all the blood samples were negative, indicating the rats themselves were not infected and supporting the conclusion that the rats were mere mechanical carriers for the virus. Besides, autopsies and examination of 14 rats trapped in Amoy Gardens also showed no gross abnormalities.
*The findings were announced by the Government on April 17 last year, including the fact that the SARS coronavirus had been found in rats.
*The investigation report also stated that as the rats showed no signs of SARS coronavirus infection, the findings only point to environmental contamination and that pests were likely to be no more than mechanical carriers for the virus in the Amoy Gardens outbreak.
*These findings of the Government's investigation were subsequently supported by an independent investigation conducted by a separate team of WHO experts, the results of which was announced on May 16 last year.
Ends/Saturday, February 28, 2004
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