The Times of India, dated 27th May, 1998 had
carried a newsitem under the heading "British
Epidemiologist Suggests Strategy to Combat Malaria".
Going by the newspaper report, Dr. Menno Jan Bouma,
Epidemiologist from the London School of Hygiene and
Tropical Medicines has suggested spraying our cows,
goats, buffaloes with insecticide as a measure to combat
Malaria. This appears to be a case of the cure being much
worse than the disease itself.
The solution suggested does not fully take into account
what is known today about how insects behave, insecticide
behaviour or the interaction between the two in the
environment. Firstly, the process through which
mosquitoes or other insects are able to take care of
themselves: When an insecticide spray is used (as has
happened in the case of DDT, BHC, Malathion etc.) it
probably kills 97 - 98% of the initial population in the
first round. The surviving 2 - 3% become the base for the
next 100% population and in the second round, the
insecticide will have a lesser mortality rate, may be 92
- 93%. This 7 - 8% then forms the base for the next 100%
percent and the process goes on. Each time the numbers
surviving increase a little more and the effectiveness of
insecticide goes down a little less. In the case of
mosquitoes they would be having 8 generations
(inter-generational gap being a month and a half) within
a year, so that in just 2 - 3 years the insecticide would
loose much of its value containing the mosquitoes. Simply
saying that the mosquitoes have become resistant and
trying another chemical insecticide is really forgetting
that the process through which the mosquitoes have become
resistant is one that will be repeated time and again.
Secondly in the manner in which one gets vaccinated and
develops immunity. Insects and bacteria also manage to
become resistant to these chemicals in the course of
time. These chemicals often act by attacking the
ribosomal apparatus which synthesizes proteins. They
become resistant by changing the shape of the ribosome; a
process called mutation. There is yet a third process
with which insects build up their defence mechanisms,
called ‘transferable drug resistance’
Information on this can even be transferred by a survivor
simply by cell to cell contact between bacteria to which
the insects are hosts. This transfer of information
enables the bacteria to develop certain enzymes, which
break down the molecular links of the pesticides to make
them harmless as chalk powder.
The write-up does not give any details of the type of
insecticides suggested i.e. Organo Chlorines, Organo
Phosphates, Carbamates, Synthetic Pyrethroids etc. Each
of them has its own specific set of problems with respect
to the environment, break down products and the manner in
which it affects all kinds of life (birds, insects,
reptiles, fish, livestock and ultimately humans). It is
important to remember that many of these insecticides
form chemical bonds with the fats in the milk and these
are not heat destructible. Therefore the milk would carry
these poisons into human consumption. Some classes of
such insecticides, biommagnify within the natural
environment and also bioaccumulate in the living fat
tissues of both human and livestock. This is why, India
already has the credit of having the highest level of DDT
and BHC in human breast milk. Other effects like
carcinogenicity, mutagenicity, endocrinal, hormonal and
reproductive impacts etc. are now clearly established.
The next issue is the one of such interactions within our
overall environment. To say that this will not be a
problem is being unrealistically optimistic, since the
Antartic Krill (a type of fish) has already acquired
toxic PCBs in its body, when no such chemicals has been
used anywhere in the vicinity. Another aspect is that the
bacteria and insects which survive the spraying of
livestock would have become resistant and we do not know
what would be their impacts on agriculture and livestock
in the future.
With factory farming of livestock being a regular
practice in the West, practices like spraying of
livestock was common place (now banned or severely
restricted on productive animals), but then they have to
their credit also, the Mad Cow Disease, Chicken Flu, and
other achievements. Contamination of meat and dairy
products is a certainty. Exports of such contaminated
matter will become impossible. Are we prepared, like our
western counterparts to mercilessly and indiscriminately
slaughter thousands of animals, including the poor
man’s goats and sheep, if the occasion warrants it?
And, would it be practical and feasible to do so, given
the realities in which we operate? Must we then create
conditions for similar things to happen in our country?
Out there, there are strict restrictions on milk coming
into the market-place for 12-15 days after they have been
given antibiotics or sprayed with insecticides. What do
we have here, and how do we enforce it?
This is just a tiny bit of the evidence available today
to show that what is being proposed is highly
inadvisable. By all means, consult experts wherever they
are available, but let the final judgment and decision be
ours. Gandhiji advised us to keep our windows open and
let the winds of all cultures come in BUT never to get
swept off one’s feet or carried away by any one of
them. We can and must contain Mosquitoes and Malaria, NOT
eliminate it unless we run the risk of eliminating
ourselves, over time.
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