Latest update in Swine Flu. Over 70 confirmed cases in US, Canada and Mexico. WHO alert level raised up to 4 – which means verified human-to-human transmission able to cause community-level outbreaks. Significant increase in risk of a pandemic.
This is certainly worrying and I have students who are now studying in the states. Hope they will be fine.
Thought this was a good biology lesson to discuss why certain diseases in animal hosts seem to have an easier time when crossing the species barrier to infect humans. We have bird flu, SARS, pigs.. the usual suspects.
Jared Diamond’s article on domestication of plants and animals in Nature Reviews (2002) [Diamond, J. 2002. Evolution, consequences and future of plant and animal domestication. Nature 418 pp700 – 707] offered a keen insight on this phenomena.
“The main killers of humans since the advent of agriculture have been acute, highly infectious, epidemic diseases that are confined to humans and that either kill the victim quickly or, if the victim recovers, immunize him/ her for life. Such diseases could not have existed before the origins of agriculture, because they can sustain themselves only in large populations that did not exist before agriculture… The mystery of the origins of many of these diseases has been solved by molecular biological studies of recent decades, demonstrating that they have evolved from similar epidemic diseases of our herd domestic animals with which we began to come into close contact 10, 000 years ago…. For instance, measles and tuberculosis arose from diseases of cattle, influenza from a disease of pigs and ducks..