Scientists warn: the Sars epidemic is only the beginning * Outbreaks of more severe epidemics are on the horizon
Alex Doron
The Sars virus, which killed hundreds, hospitalized thousands and horrified millions - and all within just seven months - is only a "general recurrence". The World Health Organization stated last week: "This outbreak has been stopped." The American health minister added: "But it will return in the fall with more force." Many other scientists warn: "Other, even more serious, epidemic outbreaks of infectious diseases are already visible on the horizon."
Among the concerns - according to the "Los Angeles Times" - the well-known flu virus after it undergoes a change, a mutation: it will "borrow" genetic information from another virus - for example the bird flu virus - and become more threatening and deadly.
Or: an as-yet-unknown virus, now developing "secretly" in a powerful place in the world, waiting for its opportunity to break out and spread rapidly.
Among the reasons for the situation: the Earth, which is much more populated than before, serves as an excellent "Petri dish" - a perfect substrate
For turbulent, rapid cultures of viruses.
At the beginning of the 20th century, only 1.5 billion people lived in the world - and now, over 6 billion. The overcrowding, the much movement from place to place, from country to country, on planes, trains, crowded buses - also transports viruses such as Sars, or influenza and mosquitoes infected with viruses such as West Nile fever, or dengue fever.
Also the fact that masses of people still live in close contact with viruses that are stored in animals and farm animals, contributes to the proliferation of viruses and the risk of disease. as well as the development of the food industry where animals are stored in crowded tanks for slaughter and processing, and these transmit viruses between them - and from them, to the people who take care of them. Complete containment and elimination of microbes - a collective name for bacteria and viruses - is not possible.
Human activity as a vaccine and effective treatment of waste water and water should help in the constant war against disease-causing agents. But at the same time, humans contribute to their proliferation and spread, with the help of unsafe sex, use of drug syringes, uncontrolled blood transfusions.
Epidemics have always been - and will be. They are not alien to man. In the 14th century, the "Black Death", the bubonic thing, raged: it broke out in China, spread to Europe, killing 25 million people, about a third of its population. Smallpox, the "spotted monster", crossed the Atlantic to America in the 16th century, making names for the Aztecs and the Incas. Influenza struck the ancient Greeks and Romans, and in 1918 claimed the lives of 20 million people in the world, out of 100 million who fell ill.
Among the causative agents of the more serious, threatening diseases that are now "in the crosshairs" thanks to modern biomedical measures: the Sin Nombre virus. Until 1993 no one had heard of him. Stored in a mouse body - American field Deer Mice(). Only those who came in accidental contact with fragments of his urine, saliva and feces were infected with it. Several warmer and more humid winters than usual brought plenty of food for these animals, which multiplied greatly - and spread the virus. In a relatively remote area in the south-west of the USA, the so-called "four rays", a mysterious disease of the respiratory system broke out in '93. This is how the virus was discovered and since then, another 25 of his relatives. He has now been flagged as a threat.
And so is the Nipah virus, which was unknown until five years ago. Stores in a bat, jumps from it to a pig - and from there to a person. Spreads fatal meningitis. Thrives in Malaysia. In 1999, 100 people died there.
But the flu is still the seasonal threat, the big one. kills thousands every year (and in the USA alone, 36 thousand patients!). Among the reasons why this virus is problematic: its genome is not made of DNA, genetic material like ours, but RNA, in the process of its transcription, many "mistakes" occur. The result: the virus accumulates successive genetic changes. Mutations. Therefore, every year, the type of flu vaccine given is different.
The influenza virus genome is divided into 8 separate segments, each responsible for a different protein among the proteins that make up the virus. Therefore: if two different virus strains infect any cell in the body, they actually mix there. The result: a completely new strain, perhaps even several strains, of the virus emerges.
When parts of the bird flu virus mix with parts of the human virus - this often happens in the body of a pig, where they both "live happily ever after" - there are major changes in the properties of the virus. New strains unfamiliar to man and his immune system, begin to attack, causing death and the spreading epidemic.
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