Rezultanta

Why do some diseases become pandemic?

Pandemic of the plague, also known as Black Death, from 1348 to 1361, killed 24 million Europeans, which meant a quarter of the population of the Old Continent at that time. Even more catastrophic was the pandemic of Spanish Flu, which in 1918 and 1919 took away 50 million lives all around the world.

Scientist today know that pandemic, the transnational spreading of a contagious disease, can be caused only by the very efficient viruses, which are quickly caught by many people and then transferred to others by human contact. The efficiency of viruses depends on the way they ''work'', procreate and transfer. For example, HIV, the AIDS virus, is transferred by sexual contact and blood, which means that by appropriate protection measures, such as the use of condoms, it can be prevented. But, HIV is much more ''intelligent'' than the Ebola virus because it is transferred unnoticed. The Ebola virus, on the other hand, kills its host in 24 hours, so it is kept only on limited areas.

In last years scientists warn us that the greatest pandemic talent could be displayed by the bird flu virus, H5N1, which killed almost 200 people since 2003. The virus has so far been spreading from infected animals to humans, but if it mutated and started spreading by human contact, there would be a pandemic, which could take away up to 100 million lives. But, when will this pandemic appear (and will it appear at all), nobody knows.