The H1N1 influenza viruses consisting of a mixture of human, swine and bird strains (H5N1) are not new, they have been found before throughout history of mankind. However, there is a sense in which this virus could be regarded as partly man-made.Flu viruses contain 8 strands of RNA, which code for 10 proteins. If two flu viruses infect a cell at the same time, new viruses budding from that cell can contain a mixture of RNA strands from the two original viruses, this is a phenomenon called re-assortment. This Recombination, "cutting and pasting", can also produce some evolutionary mixing within RNA strands.
Vaccines such as Tamiflu (Oseltamivir) and Relenza (Zanamivir), are not totally effective against viral strains
It is unusual to be infected by two flu viruses at the same time, and even rarer for one of those viruses to come from another species altogether, but it does happen, especially in pigs, which are susceptible to both human and bird flu viruses. Repeated re-assortments can produce mixtures like that found in the swine flu virus now spreading worldwide.
Again it is not a new phenomenon. There was re-assortment between bird and human flu viruses in pigs in Italy during the 1980s and in the 1990s, a H1N2 swine flu circulating in pigs in the UK was found to be a mixture of swine, human and bird flu strains resulting from multiple re-assortments.
It is not yet clear exactly when and how Mexican swine flu strain evolved, but it could certainly have happened without the help of genetic engineers. Despite this, the swine flu could still be regarded as man-made.
Mounted Policeman in Mexico City sports a facemaskThere are now over 6 billion people on the planet, and each year we raise more than a billion pigs and perhaps as many as 70 billion chickens. The result is a paradise for influenza viruses, which can lie dormant for long periods.
The problem is not just the sheer number of potential hosts. The conditions in which animals are kept can favour the evolution of new and deadlier strains.
Par example, in the wild, flu viruses can be self-limiting. The nasty flu strains that make animals too ill to walk or fly are unlikely to spread far. In crowded factory farms, they can spread like wildfire, helped by the global trade in animals and the distribution and transportation of animal products.
Vaccines such as Tamiflu (Oseltamivir) and Relenza (Zanamivir), are not totally effective against viral strains
The intimate interaction of farm workers with animals, especially on small-holdings where pigs, ducks, chickens and children all happily intermingle, also provides plenty of opportunities for viruses to jump species.
Animal vaccines might seem like the answer, but vaccines e.g Tamiflu (Oseltamivir) and Relenza (Zanamivir) that do not provide 100% protection can actually make things worse. Vaccines are not totally effective against viral strains. When there is widespread vaccination, viruses can mutate and spread without any visible disease. Viruses are smart. Ineffective vaccines also create strong selective pressure driving the evolution of new strains that can dodge the immune attack provoked by the vaccine.
Already, attention is turning to the big pig farms in Mexico, and the role they may have played in creating this new strain of swine flu but all intensive pig farming is a 'risk' and 'at risk'.
The undeniable and scary fact is, that we still know so little about flu and what makes it capable of spreading from human to human. This means that analysing and reverse engineering a virus of this kind and developing an anti-virus, would be a huge challenge.
Yes, it's possible that this virus was created by a mistake at a research laboratory or a vaccine factory and it is more possible that a virulent strain has been accidentally released into the wild, as has happened many times before and the most plausible explanation is, that this monster is the long-predicted product of our farming system.
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