Business
Infectious diseases spreading due to global warming: Study
Washington, Feb 16
Climate change has
triggered the spread of infectious diseases in new places and new hosts
such as West Nile virus and Ebola, an alarming study shows.
Researchers
from University of Nebraska-Lincoln in the US warn that humans can
expect more such illnesses to emerge in the future as climate change
shifts habitats and brings wildlife, crops, livestock, and humans into
contact with pathogens to which they are susceptible but to which they
have never been exposed before.
“It is not that there is going to
be one 'Andromeda Strain' that will wipe everybody out on the planet.
There are going to be a lot of localised outbreaks putting pressure on
medical and veterinary health systems,†said noted zoologist Daniel
Brooks.
Brooks and co-author Eric Hoberg, zoologist with the US
National Parasite Collection of the USDA's Agricultural Research
Service, have observed how climate change has affected very different
ecosystems.
They have witnessed the arrival of species that had not previously lived in that area and the departure of others.
“Over the last 30 years, the places we have been working have been heavily impacted by climate change," Brooks said.
“Even
though I was in the tropics and he (Hoberg) was in the Arctic, we could
see something was happening. Changes in habitat mean animals are
exposed to new parasites and pathogens,†he noted.
Brooks calls it the “parasite paradoxâ€.
Over time, hosts and pathogens become more tightly adapted to one another.
According
to previous theories, this should make emerging diseases rare because
they have to wait for the right random mutation to occur.
However, such jumps happen more quickly than anticipated.
Even pathogens that are highly adapted to one host are able to shift to new ones under the right circumstances.
“Even
though a parasite might have a very specialised relationship with one
particular host in one particular place, there are other hosts that may
be as susceptible,†Brooks pointed out.
In fact, the new hosts
are more susceptible to infection and get sicker from it, Brooks said,
because they have not yet developed resistance.
The article was published online in the journal Philosophical Transactions of the Royal Society B.