The crew of Star Trek used to regularly find themselves admiring the beauty of whatever planet they’d just landed on – only to get sprayed by or tangled in some piece of the local biology that turned out to be lethal to the extraterrestrials. But you don’t have to go to the other side of the galaxy; the same thing is happening right here on Earth. The more we go marauding into forests and other places where we don’t belong, the more deadly consequences we’re unleashing on ourselves.
Science writer Jim Robbins explains “the ecology of disease” in a weekend article in The New York Times:
Teams of veterinarians and conservation biologists are in the midst of a global effort with medical doctors and epidemiologists to understand the “ecology of disease.” … Experts are trying to figure out, based on how people alter the landscape — with a new farm or road, for example — where the next diseases are likely to spill over into humans and how to spot them when they do emerge, before they can spread.
More than two million humans are killed every year by diseases they’ve contracted from other animals. Swine flu and bird flu are only the most well known. Robbins gives the example of the Nipah and Hendra viruses, which are carried by flying foxes who are largely immune to their effects. (At worst they catch the equivalent of a cold.)
But once the virus breaks out of the bats and into species that haven’t evolved with it, a horror show can occur, as one did in 1999 in rural Malaysia. It is likely that a bat dropped a piece of chewed fruit into a piggery in a forest. The pigs became infected with the virus, and amplified it, and it jumped to humans. It was startling in its lethality. Out of 276 people infected in Malaysia, 106 died, and many others suffered permanent and crippling neurological disorders. There is no cure or vaccine. Since then there have been 12 smaller outbreaks in South Asia.
Part of a larger graphic illustrating hot spots for emerging diseases around the world.
AIDS crossed into humans from chimpanzees in the 1920s when bush-meat hunters in Africa killed and butchered them. West Nile virus came to the United States from Africa and then spread through robins, who are frequently bitten by mosquitoes. Lyme disease is harmless to most animals in the wilds of the American northeast, but as suburbia took over more and more forest land, wolves and owls and other predators were chased away, leading to a huge increase in white-footed mice whose weak immune system make them well-suited to carrying Lyme bacteria, which are picked up by ticks … and eventually spread to the humans now living in places to which we’re not adapted.
The more we invade tropical forests, the more we import exotic pets, the more we kill and eat exotic species, the more we expose ourselves to pathogens to which the other animals have natural immunity and to which we have none.
Check out the whole article here.