By Barrett, Michael
New Statesman (1996) , Vol. 138, No. 4947
Private Lewis had suffered a sore throat before. He knew that feeling lousy wasn't a good excuse for not performing to the best of his ability. Against medical advice he joined his fellow US army recruits on their all-night hike, in New Jersey, in January 1976. A few hours later he collapsed. He was carried back to Fort Dix army base but died shortly afterwards. Lewis's death, from swine flu, provoked nationwide panic of the kind we are already beginning to witness in Mexico and now the United States, where California has declared a state of emergency.
The thought of insidious aliens gnawing away at us from within is, as the new swine flu scare reminds us, terrifying. So just how bad might this pandemic be? Scientists have for several years been saying that a global outbreak of influenza is overdue. But after keeping a fearful eye on the H5N1 strain of avian flu it seems that an H1N1 swine flu strain from Mexico has taken us unawares. Its rapid spread is no surprise. Flu can be astonishingly contagious once it acquires characteristics enabling transmission from human to human in aerosols from coughs and sneezes. H5N1 (which kills one in two infected people) has yet to evolve in this way. Its victims have been predominantly poultry farmers who were in persistent contact with infected birds.
Flu viruses are transmitted as tiny particles containing a collection of RNA fragments, each representing one of the virus's genes. In order to read this information and generate new viral particles the pathogens must enter living cells (usually in the respiratory tract) and hijack their gene-expression machinery. Eventually a multitude of replica viruses bursts from the cell, destroying it. The efforts of the body to attack the virus can cause even more severe damage. Secondary bacterial pathogens can colonise this impaired respiratory tissue and contribute to our demise.
The influenza virus has an array of tricks that has made it so difficult for us to control. For a start, it is difficult to speak of one single virus. There is a multitude. The terms H5N1, H1N1 and so on refer to small molecules on the viral surface that control their ability to enter and leave host cells. These proteins are recognised by our immune system and we can, in time, generate antibodies that neutralise the virus. However, each H and N variant is quite distinct; antibodies generated against H1 do not recognise H5, for example. Immunity to one strain is not carried to others and, unlike the case for some other viruses--measles, for instance-we can be infected repeatedly by flu throughout life.
Flu viruses are widespread and can infect a multitude of animals (pigs and birds being just two examples). Dozens of distinct H and N types exists. Rarely, two or more different flu viruses might infect the same animal cell at the same time. The RNA gene fragments can mix and re-assort to create novel, chimeric viruses. These can carry new properties (for example, airborne transmission and hypervirulence along with a new and previously unrecognised set of surface proteins).
Already, some depressingly predictable examples of infection bigotry have emerged. Several Asian governments have banned imports of Mexican pork, even though there is no evidence that this particular "swine" virus emerged from pigs. Nor can flu be transmitted through meat. On Monday, Indonesia's health minister won the race to make the standard conspiracy claim of the virus being a man-made bioweapon. Writing in the Guardian, Mike Davis, author of a book on flu, blames the global meat industry while failing to note the regularity with which these pandemics have emerged through history, predating the (albeit disgusting and greed-driven) practices of intensive farming.
Pandemics begin when variants of viruses to which humans have never been exposed before suddenly appear--so no immunity is present within the "herd". …