Anthrax as a
potent wildlife killer
In the
backdrop of the current frenzy being generated by anthrax amongst
fear-crazed humans in some parts of the world, it may be a good
opportunity to spare a thought for the threats that are posed by anthrax
on many vulnerable wildlife species.
Anthrax is
basically an animal disease that has a long-recorded history, which
means that it has been occurring in domestic cattle for hundreds of
years. During all this time, it has not been credited with causing any
serious disease of epidemic proportions in humans, although stray cases
of infections have always been reported from amongst people working
closely with cattle or sheep.
It is caused
by the bacterium Bacillus anthracis that regenerates itself
through the formation of long-lasting spores. These spores have the
inherent capability of dormancy, which enables them to survive for a
long time in the environment. Grass-eating animals, including wild
herbivores, are prone to infection because they are more likely to
ingest anthrax spores living in the soil. Although the remedial practice
of animal vaccination, or in case of an outbreak, the destruction of
infected herds, has been instrumental in checking the disease, anthrax
spores still continue to be found in soil samples from all over the
world.
In far as
wild species are concerned, all mammals are susceptible to infection,
but as stated earlier, it is the herbivores and grazers that are more
vulnerable. Once the anthrax infection is established in herbivores, it
ultimately causes death, with the carcasses exuding dark tarry blood
from body orifices. Unless quickly found and disposed off by burning,
these carcasses are fed upon by wild scavengers like the hyaenas and
jackals, and thereby the spores are spread across to other places,
including waterholes. The spread of contamination is further augmented
by flies and other insects that feed on the carcasses, and transfer the
spores to surrounding vegetation.
As has been
documented in a recently televised film on African wildlife, an outbreak
of anthrax in Kruger national park – if memory serves one right - also
caused lions to become infected after they had fed on anthrax carcasses.
It was heartrending to see large prides of infected lions, with
grotesque and swollen faces, slowly but surely dying even after all the
ministrations of the committed park staff. However, the subsequent
operation they launched in disposing off the carcasses by burning, and
disinfecting large areas around where the outbreak had occurred, gave a
graphic insight into the huge human and logistic effort that wildlife
managers in that country are capable of mounting.
In India
however, our forests and wildlife have either not been afflicted with
any anthrax epidemic of notable proportions, or have not identified it
as the cause in cases where wildlife has been reported to die in
substantial numbers. The most recent scare of a possible anthrax
outbreak in an Indian forest that comes to mind, is the report in the
Assam Tribune of August 15, 2001, which mentioned the death of seven
wild elephants in the Nameri national park. According to the report, the
Sonitpur district veterinary department suspected that the unnatural
deaths of the wild tuskers could be due to anthrax, which had reportedly
spread in an epidemic form in the nearby forests of Arunchal Pradesh.
Unfortunately, a lack of a follow up on that report has not provided any
confirmation whether it was indeed anthrax or not. But what one does
hope is that such an outbreak does not touch our forests and wildlife
because it would be very presumptuous and optimistic to hope for such
remedial operations in India, as were mounted in that national park in
Africa.