*********************************************************
The following is the transcript of the English portion of the question-and-answer session given at the press briefing by the Secretary for the Environment and Food, Mrs Lily Yam, the Acting Director of Health, Dr Paul Saw, the Deputy Director of the Food and Environmental Hygiene, Dr P.Y. Leung, and the Assistant Director of Agriculture, Fisheries and Conservation, Dr Leslie Sims today (May 16).
Question: Can you tell me how many birds have died so far and how many more will be slaughtered at these markets, and how many poultry sellers will actually be affected at these three markets?
SEF: Yes, at Yeung Uk Road Market, 763 birds have died as at noon today; in Fa Yuen Street Market the number was 5; in Smithfield Market the number is 29. Now, as for the number of stalls, there are 24 poultry stalls in Yeung Uk Road Market, 4 in Fa Yuen Street Market and 10 in Smithfield Market. The number of workers, including the owners of these stalls, for Yeung Uk Road Market is 60, Fa Yuen Street Market is 8, Smithfield Market is 17.
Question : And how many birds will be slaughtered?
SEF: In Yeung Uk Road Market, the number of chickens to be slaughtered would be 2,200; Fa Yuen Street Market is 1,000; Smithfield Market is 1,500.
Question in Chinese: (source of infection?)
SEF: Dr Sims, how can birds be infected? Surely, the sources of infection are not confined to farms.
Dr Sims: There are many, many possible ways that a virus can enter a market. We know that there are H5N1 viruses existing in the environment and we have had previous cases, for example, the Shek Tong Tsui Market in April this year, where we found a virus in the market. Viruses could come in in many ways, they can come on people's clothes, they could come on cages, they could come from waterfowl if they are illegally placed in the market, which we assure you they are not. Many, many different routes could actually allow for the introduction of these viruses. We have to have monitoring systems at all levels of our production system, at all levels of our sales system, to make sure that we find things - when we do find things we make sure we act immediately to protect public health.
SEF: How did we discover the viruses? Can you describe very briefly, just to satisfy our friends from the media, the process - you know the process of discovering this particular virus in the three markets. Very briefly.
Dr Sims: Briefly, as I say we work in co-operation with the Hong Kong University in doing our surveillance programmes in the markets. They have their surveillance programme, we have ours. Whenever we find viruses we share them with them, we share information with them. In this case they had been studying some markets and they have actually found some virus in these markets. As soon as they advised us of those findings we have gone back to those markets to basically find out whether these virus were still present in those markets and we have now discovered that is the case. So as soon as we got that information in early May we have gone into these markets to check to see what the situation is now and from that we have found the viruses. At the same time, today, we also have the discovery of the dying birds from yesterday and today.
Question in Chinese: (on test samples)
SEF: Dr Sims, can you concentrate on two things. The first, whether there are any remaining samples whose results are not yet known? That is the first question. The second question is: Of the samples, the results of which are already known, what further tests would be conducted and when would you know the final, final result?
Dr Sims: The situation now is, we have taken samples from each of the three markets and these are still being cultured at the moment. We have results from some of these and we have found we have H5N1 viruses. What we need to do now is to actually do more characterization of those viruses, to do more through working with the Hong Kong University to get more information on the actual internal structure of these viruses to find out what genes they contain. We already have some preliminary information on that on which we can say these are not the same as the "Chicken 97 virus".
In terms of the outstanding samples, we have a continual throughput of the samples going through our laboratory, so at the moment we have approximately 300 samples, which are being processed, from markets, and these results should be available in the next few days. But this is an ongoing process; we are continually going to markets to monitor, to see the situation.
Question in Chinese: (on different types of H5N1 virus )
Dr Sims: As you may be aware from our discussions last time when we were talking about the Shek Tong Tsui Market, we did say that we had had a number of H5N1 Goose 96 like viruses isolated from waterfowl in the Western Wholesale Poultry Market, and these are the commonest type of virus we have been seeing. What we do now know from the preliminary work we have is that the virus we have now is slightly different - it is still goose-like but it has some other characteristics which are not the same as the Goose 96 virus.
As far as what happens with these virus from the three markets, again this is the first time we have had a virus which causes disease in poultry in a retail market since 1997. Clearly, this virus can cause disease very quickly in poultry, as we've discovered in the last two days, where we have found birds which are rapidly dying as a result, and these birds may only require 24-48 hours before they will actually die as a result of infection from the virus.
Question (BBC): Can I just be clear that this virus, this H5N1, is this a new strain that has not been seen before and is that why you're -- or is it something that has been seen before and that is why you are saying you're confident it can't affect humans?
Dr Sims: From the information we have at the moment it is still based on the Goose 96 virus but it has some evidence of some early reassortment with some other viruses from waterfowl. So we have some changes in the virus from the one we saw, say in Shek Tong Tsui Market in early this year. So it is a slightly different virus but it does not have the characteristics of the Chicken 97 virus, it is quite different from that virus.
Question in Chinese : on whether the virus will affect humans.
Dr Saw: I think from the available information on this virus, we have no indication that it is able to cause infection in man. The Secretary has made a point that as a precautionary measure - because flu viruses have the potential to combine with another virus to form new viruses, that is why we are taking the precautionary measures to clean up the markets.
Question: What are you looking for? I understand that the 1997 virus, you haven't fully taken ... (inaudible) in the 1997 outbreak. So what sort of fowl or a strain are you looking for? Have you alerted the WHO and also the International Flu Collaboration Centre about this outbreak?
SEF: Yes.
Dr Sims: What we are looking for is to basically analyze the 8 internal genes of the virus to see whether they are the same or different to those which were found in Chicken 97. Now at the moment we are not finding anything in these viruses, which is the same as the Chicken 97, except for the H-gene, which has been common to all the viruses we have found in Hong Kong so far. So it does not share any of the other features of Chicken 97.
Question: But you're saying already that it's 100% sure that it won't affect human beings?
SEF: No, we didn't say a 100%.
Dr Saw: We said that as far as we know, up to the present moment it is not infecting man.
Question: Even suspected cases? There are no suspected cases at all?
SEF: No.
Dr Saw: No.
Question: I just want to know whether it is only the chickens which are infected?
Dr Sims: For this particularly virus - again you must remember we have a segregation policy for ducks and geese. All of our ducks and geese coming into Hong Kong are segregated at all stages of production and they are slaughtered in the Western Wholesale Poultry Market, so there are no live ducks and geese in any of our retail markets.
Question: I understand you said that in early May you felt there wasn't the need to take such drastic measures as today, but how can you be sure that between then and now the virus hasn't been leaked beyond these three markets?
SEF: Well, nobody can ever be sure of anything, particularly where viruses are concerned. I explained just now that in taking such a decision we have to make sure that we do so on very firm grounds and on the basis of test results alone, we don't think that such action is warranted. On the one hand, there is a need to ensure that the markets concerned are completely rid of these viruses, so that we can safeguard both veterinary and public health. On the other hand such action is not to be taken lightly because of the impact it would have on stallholders.
Question: Then it took you, like three weeks now or two weeks now, before you took action, and then but at the same time you cannot trace the source of these chickens.
SEF: We are tracing the source of these chickens. We didn't say we are unable to trace the source of these chickens.
Question: Yes, but how long does it take you to trace the source of these chickens?
SEF: We are doing it as soon as possible. And don't overplay the importance of tracing the source of the chickens. We tried to explain many times just now that chickens can be infected in various places because viruses can be present in the environment, in the atmosphere and so on.
(Question in Chinese)
Dr Sims: We already have information from the Hong Kong University about the structure of these viruses and the information we have is that these viruses are not the same as the Chicken 97 virus. So we already have genetic information on these viruses. Yes, we will do more viruses to be sure, but again the action we are taking today is to remove any viruses from the markets anyway. So these results will be interesting results but the main critical thing is that we are taking action today to remove these viruses from the markets anyway. But the likelihood is that these viruses will be the same as have already been found by Hong Kong University.
Question: So, is it right to say that there is still a threat among these viruses? That is to say, the virus may still pose a threat to human health. Can we say that? There is still a possibility there because you haven't got all the information so far.
Dr Saw: Let me answer your question and let me be a little long-winded. When the Secretary said that the isolate this time is not the same as 97, this is as far as the gene sequencing is concerned. What you are trying to say is the Chicken 97 is similar to this isolate because they are both H5N1. Just like you and I are of Chinese origin, we are the same Chinese origin but you are different from me. So you have to draw the distinction. The gene sequencing shows that this is totally a different virus from 97. But they are both the same in H5N1. In that perspective they are similar.
Your next question is: Does it pose a threat? The Secretary has said that we are taking this action today as a precautionary measure because we recognize that flu viruses will always have the potential to mix with one another and form new viruses. Because of this we are doing what we are doing today. But in as far as the present virus is concerned, and based on what we know now, it does not infect man.
Question: In the absence of a diagnosed case of the flu in a human being, can you tell us a bit about the test you do that leads you to the conclusion that it does not affect humans?
Dr Saw: First, I must explain that I have a surveillance system also for man, and the surveillance system for man is the most comprehensive in the world. We have doctors in the private sector and all the government clinics and all the hospitals to take samples from patients with symptoms suggestive of flu. This is done on a continuing basis. Up to today, I have no viruses on type in the lab. It means that all those viruses related to flu have been typed and they are not H5N1. Does that answer your question?
Question: Well, yes. But I guess one lingering question is, given that since this is a new strain that you are still in the process of either doing culture ..., isn't there a possibility that you might, next week, get a virus type to this particular strain. I mean what is to bring you to the unequivocal conclusion that it can't affect humans if it is a relatively new strain?
Dr Saw: We say that up to the present moment, based on the information we have, this virus is not known to infect man.
Question: But you are not ruling out the possibility that it could?
Dr Saw: It can always re-assort and all that.
Question in Chinese : on whether checks for workers
Dr Saw: Just now I mentioned that my colleagues have gone down to contact the stallholders and they would be examined but in as far as testing of blood is concerned, our experience with the 97 Chicken Flu, the test to diagnose the infection is not very sensitive. We had to rely on other tests. And we will do whatever tests if there is an indication but the stallholders will be under surveillance.
Question: Is the current strain unique? Have you discovered that before?
Dr Sims: This is the first time that this particular strain has been found. But again, I think we have to look at what happens with influenza viruses. Influenza viruses are always changing. They are always changing their genetic material, so it is not unusual to find a new influenza virus; they are being found all the time. What we have here is just a different type of H5N1 but it is not the Chicken 97 virus.
(please also refer to the part on Chinese version)
End/Wednesday, May 16, 2001
NNNN
