The number of malaria cases in SA
has dropped dramatically over the past seven years, largely as the
result of the widespread use of the controversial pesticide DDT.
Despite
the positive results, a number of academics have cautioned about the
use of DDT and warned of side effects, particularly environmental
effects and the impact on fertility rates among women who have come
into contact with the pesticide.
Statistics released by
the health department show that since the reintroduction of DDT,
malaria cases have dropped significantly. In KwaZulu Natal there has
been a 99% reduction, in Mpumalanga 92%, and in Limpopo 70%.
Over the past high-transmission season, which
ended in March 2007, 1 263 people were infected with malaria and only
seven died. This compares with 1999-2000, just before DDT was
reintroduced, when 64 222 cases and 458 deaths were recorded.
DDT
has a controversial history and the side effects of its uses on fruits
and vegetables in the 1960s and 1970s resulted in an almost complete
ban over the subsequent two decades. But health officials in Southern
Africa have found that if sprayed in tiny amounts once or twice a year
on the inside of homes, DDT can keep out 90% of mosquitoes.
But
activists and some academics are again urging the use of alternatives
to DDT. University of Cape Town professor Leslie London says "in the
long term, DDT is something that needs to be phased out - the question
is how quickly and what to replace it with.
"DDT is
well-recognised as environmentally persistent, and a problem for
animals. For humans, the evidence is not as strong but certainly
sufficient to be of concern, particularly in pregnant women.
"The
notion that DDT is safe for humans is nonsense," London says. "So, the
issue is not that DDT is safe, but that the use of DDT may be justified
if it can prevent deaths from malaria.
London says the
success of the DDT campaign against malaria has much to do with the low
cost of DDT, making it affordable for health authorities. "But the side
effects are not built into the cost-benefit analysis," he says.
London
and Leslie Liddell, director for Biowatch SA, urge greater use of
alternatives to DDT, such as bed nets, other insecticides and greater
control of open water-collection sources. Though these options are
expensive and not easily accessible, they would be safer than DDT, they
argue.
But proponents of the use of DDT argue that it has
had a high and immediate impact in reducing malaria, whereas bed nets
and other methods have only a gradual impact.
Mbulelo
Baloyi, spokesman for KwaZulu Natal's agriculture & environmental
affairs department, says: "We did satisfy ourselves that DDT has no
effect on the environment. We monitor any irregularities that occur in
the environment and none so far have been due to the reintroduction of
DDT."
Jasson Urbach, an economist with the Free Market
Foundation's health policy unit, is critical of the persistent warnings
about DDT: "This is a smear campaign and no-one has actually found
conclusive evidence for their claims. Authorities should continue to
use DDT rather than worrying about imaginary risks."
While
SA, Swaziland and Mozambique have recorded a sharp drop in malaria
cases, Uganda has been a more reluctant adopter. It s exporters are
fighting the government's decision to reintroduce the pesticide. If
residues were detected in agricultural produce, Europe would ban all
imports from Uganda.
But Rajendra Maharaj, an antimalaria
project leader, says "there is almost no environmental contamination
when you use DDT properly"
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