More sting with DDT use

Donald Roberts | 14 Oct 2010
New Straits Times
Health Ministry director-general Tan Sri Dr Ismail Merican said no country used DDT (a synthetic insecticide) to control dengue.

He added that DDT's effectiveness must be proven before countries could use it in advance of safer and more effective insecticides.

This assessment appears reasonable.

However, it ignores two facts. One is historical. DDT is the only insecticide proven to eradicate dengue from a vast landscape, for example, the Americas.

Yet, in lieu of trying DDT, Dr Ismail opts for "more innovative, newer, safer and effective control measures".

Countries in the Americas used DDT in peri-focal spray programmes to largely free them of dengue for almost 30 years.

Later, as a consequence of fearful anti-DDT propaganda and political pressure, they largely stopped using DDT by the mid- 1970s.

The countries turned to community participation, environmentally friendly methods of dengue control and other insecticides.

In tandem with these programmatic changes, dengue made a devastating return to the Americas. Fearful propaganda and political pressure from anti-DDT campaigns destroyed the Aedes aegypti eradication programmes in the Americas.

As a consequence, and in consonance with Dr Ismail's statements, residents today are repeatedly blamed for a resurgence in the disease.

Blaming communities for dengue in the Americas has remained constant from the 1980s, when dengue first reappeared in countries that were dengue free, to the present.

As part of this blame game, Dr Ismail and others tell us there are "more innovative, newer, safer and effective control measures".

People should ask what are the control measures and, if they are so effective, why does the number of dengue cases keep increasing?

Dengue's history of increase in many countries and its prevalence in others is irrefutable proof that Dr Ismail's claims of "more innovative, newer, safer and effective control measures" are as illusory as their claims that DDT is a direct cause of cancer and other health problems.

What Dr Ismail describes as harm from DDT exposure does not fulfil even basic epidemiological criteria for cause-effect relationships.

It is for this reason that the World Health Organisation still approves DDT for use in malaria-control programmes.

Opposed to authoritarian decisions against DDT, it would make more sense to conduct pilot tests of peri-focal DDT spraying.

Fair and balanced evaluations of DDT efficacy would allow a far more meaningful public health policy decision vis-a-vis DDT use for dengue control.