We can't wait for the virus to become adapted. We have to do something against them, and this is perhaps a good transition to talk about anti-viral strategies. All this work, of course, leads to certain proposals for treatment and colleagues of mine are working on this and we are at least trying to prepare some ground for it... some basis. I think of people like Esteban Domingo in Madrid with whom we co-operate.

What is anti-viral strategy? Of course, the most common is to interfere with the multiplication of the virus. In the case of AIDS this was for a long time the only way to treat patients, just to stop the replication of the RNA or DNA by... But of course such type of treatment is a very dangerous one because it stops also replication of the host cell's DNA. But in recent time, and that was already an early proposal, we came to say with such a large variability this virus has, adaptability, you have to see in advance the next steps the virus will do, so one has to study very carefully how will be the response of the virus, and one has to make sure in the treatment that you use several interferences at the same time which might leave the virus helpless and it might work. And the successes which were reported recently in the press about treatment of AIDS all are such combinations of several methods that they use, and proteases to inhibit the proteins, at the same time interfering with replication and so on. Now there is another type of treatment we could try to develop. We talk much about error threshold. Error threshold says that any replicating system, in order to keep its information stable, must be below the error threshold. It should be closed to the error threshold in order to be versatile and in order to be adaptable. But it must not exceed the error threshold. It's like exceeding a melting point, we could call it a melting point of information... the information will flow apart, and then it's gone. And one possible strategy in fighting viruses is to interfere with the replication mechanism in such a way that one perhaps finds substances that influence replicases or use replicases that are preferred in having a faster rate but making more mistakes, making so many mistakes that the virus...

[Q] Loses its pathogenic information.

Right. Loses its information and decomposes or whatever will be the consequence. But this would be an interesting way. Esteban Domingo in Madrid has tried that with some animal viruses, with foot and mouth disease virus. So at least he had shown in principle such a method works, you can deteriorate the virus by increasing the error rate. And you must also notice that error rate is not simply the number of mistakes you make and the length of the virus. It's also the fitness landscape... it's also that enters the error threshold relation, and that causes all the viruses to be different.