Holy Flying
Cats
In Malaysia, huts were sprayed with DDT to kill mosquitoes. DDT not only killed
mosquitoes but also other insects, including wasps, which normally ate moth larvae living
in these thatched roofs. Cockroaches that were found in the treated huts were fairly
resistant to the DDT. Geckos that lived in the huts ate the cockroaches and died of DDT
poisoning. Cats that ate the geckos with DDT in their bodies also died of DDT poisoning.
Due to sudden scarcity of cats in the village following the DDT treatment, rats
multiplied, which ushered the scare of bubonic plague. WHO arranged for cats to be dropped
by parachutes to the remote village to replace those that had died and to eliminate the
rats to prevent plague!
Source: J Duffs and H Worth 1998, http://www.iupac.org/publications/
cd/essentialtoxicology/IUPACDDT |
Defenders of DDT
Most advocates of DDT are economists from western
institutions. Prominent among them is Amir Attaran, director of international health,
Centre for International Development, Boston, US. He believes that the merits of DDT far
outweigh its problems. "DDT saves lives from malaria, and if properly used, causes
very little harm to the environment." Carel Jsselmuiden, professor of epidemiology,
School of Health Systems and Public Health, University of Pretoria, South Africa agrees:
"It is better to die at the age of 50-69 of cancer than to do die of malnourishment
at the age of one."
Advocates believe that over the decades, the judicious use
of DDT has saved tens of millions of lives from malaria and death. Attaran argues that the
cost of phasing out DDT and replacing it with alternative malaria control strategies may
cost countries between US $350 and $950 million annually. Another Harvard economist,
Jeffrey Sachs, has found that if malaria had been eliminated in 1965, Africa’s annual
gross domestic product would be $400 billion now, not a mere $300 billion.
The fact that some individuals have been exposed to DDT
everyday for decades with no evident affects is held as evidence of DDT’s
harmlessness. The DDT "expert" Kenneth Mellanby used to eat a pinch of DDT every
time he lectured on DDT over a period of 40 years.4 Recent evidence shows that even where
resistance to DDT has emerged, DDT repels mosquitoes from buildings that have been
sprayed. This is cited as another reason to continue use of DDT despite the knowledge of
increasing resistance in mosquitoes.
DDT's
dividend |
 |
| Source: D R Roberts et al 1997, DDT global
strategies, and a malaria control crisis in south America, Emerging Infectious Diseases,
Vol 3, No 3, p300. |
The most frequently quoted study by the pro-DDT lobby is
that by D R Roberts titled, "DDT, Global Strategies, and a Malaria Control Crisis in
South America," which notes the extraordinary rise in the number of cases of malaria
when DDT was no longer used.
Roberts comments, "No Country has ever implemented an
integrated mosquito management programme, much less tested how well it works. Perhaps more
disappointing is the fact that DDT seems the only solution for the control of a dreaded
disease like malaria and there seems no hope for new innovations." The study cites
examples of benefits in Brazil, Mozambique, Ecuador, Zambia, Colombia and Peru due to the
re-introduction of DDT (see graph: DDT’s dividend).
The pro-DDT lobby is dismissive of non-chemical alternatives to DDT, believing that
alternatives such as Insecticide Treated Mosquito Nets (ITMNs) have their constraints, and
that integrated vector control methods also require institutional innovation and people
empowerment to be effective.
Reckoning with resurgence
In India, the most strident critique of the emergence of DDT
resistance was the Public Accounts Committee (PAC) report to the Eight Lok Sabha
Committee. The PAC attributes the re-emergence of malaria to corruption and
mal-administration at the grassroots. It rests the blame on many state governments for not
contributing their share for malaria control (malaria control programmes are funded on a
50:50 shared basis by the centre and state governments). Many states did not invest in
malaria programmes until such time as malaria assumed epidemic proportions.
The PAC report comments that DDT and other pesticides were diverted by the rich and
powerful for use in agriculture, leaving the communities bereft of the benefits of the
pesticide. Communities could only manage one round of spraying (sometimes no round at
all), as against the recommended two or three rounds. Irregular application of DDT
developed resistance in mosquitoes. The scope of triple resistance is spreading. The
report also criticised pesticide-testing laboratories for not identifying fake pesticides.
The fact remains that DDT did work in India, reducing malaria incidence dramatically
from a million cases to 2,85,962 cases. But malaria resurged due to bureaucratic oversight
and improper administration. Today there are an estimated three million cases per year.
The resurgence of malaria was marked by an increasing incidence of falciparum malaria, its
deadliest form. In India, about 40 per cent of all malaria cases are falciparum.
Malaria impacts the marginalised tribal communities very harshly because they have little
or no access to medical facilities. India’s tribal population constitutes 7.8 per
cent of the total population but contributes to about 30 per cent of India’s malaria
cases and 75 per cent of malaria-related deaths, 60 per cent of which are falciparum
cases.
Increased resistance means increased use of pesticides and a concomitant increase in
the cost of malaria control programmes. Pesticide failure is also partly due to the
steadily climbing prices of pesticides. Currently, DDT and BHC constitute 70 per cent of
all insecticides used in India, and their use is increasing at a rate of 6 per cent a
year. The National Malaria Eradication Programme (NMEP) continues to insist that there has
been "no adverse reaction of DDT on human health".5 The Indian government seems
to accept NMEP’s judgment on DDT safety and routinely continues to use pesticides,
paying no attention to the World Bank’s recommendations (see box: No
change please: we are the sarkaar!).
No change
please: we are the sarkaar!
In 1997 the World Bank tried a
different trick to combat malaria. It submitted a Project Appraisal Document on major
proposed credit to India by the International Development Association (IDA), for an
‘enhanced’ malaria control project (EMCP) to be implemented by the National Anti
Malaria Programme (NAMP) of the government of India (GOI). The objective of EMCP was to
shift the financial focus of the existing programme from indoor residual spraying (IRS) to
a more diversified approach involving a higher percentage of spending on areas such as
medicated mosquito nets, institutional strengthening, epidemic response and intersectoral
collaboration, and secondly, to shift from malaria eradication to malaria control (hence
the word ‘eradication’ was dropped from NMEP, which became NAMP).
IRS was a failure because of poor operational coverage, the development of vector
resistance and the rising cost of using insecticides. Hindustan Insecticides Limited
(HIL), established by the government, mainly manufactures these insecticides. HIL is the
sole producer of DDT in India and the second largest manufacturer of pesticides in Asia.
The NAMP admitted that increased expenditure was used to pay for more expensive
insecticides, adding that selective and decreasing vector control was the way ahead.
Insecticide use had and continues to have significant adverse environmental implications,
invariably affecting the non-target organisms thereby disturbing the ecosystem.
The EMCP favoured allocating 53 per cent of existing funding to IRS (down from 69 per
cent). This new percentage would also apply to an increased fund base. The World Bank in
its own project budget allocated 40 per cent of its funding for selective vector control
allocation. The Bank envisaged more targeted spraying, increasing non-insecticide vector
control methods such as larvivorous fish and biolarvicides, and selecting environmentally
neutral insecticides, instead of indiscriminate spraying of insecticides. Sadly, the
recommendations were not implemented. In 1999, when the government of India reported on
funding allocations for malaria control in India, the share of indoor residual spraying
was again 69 per cent. |
All things considered...
Arguments proposed by the defenders of DDT are applicable only
for some select countries. India has its own unique constraints. Along with triple
resistance in some parts, double or at least single resistance is observed in many other
parts of India. DDT may only be a repellent.
The spread of resistance has been rapid, in part because of the increasing range of the
vector. According to a UNICEF study, distressed localised migration is highest in India,
with nearly 10 per cent of the population moving every year from one location to another
in search of a better livelihood. The vector uses migrating populations and their cattle
to "hitch-hike" into new areas. Rapid deforestation, agriculture, irrigation,
movement of susceptible populations and rapid urbanisation all assist the vector in
establishing itself in new ecosystems. Such problems are few in tropical countries like
Ecuador, Peru and Bolivia.
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