Dear Colleagues

Someone AT xxx.za said:

"I would like to say from the outset that reintroducing DDT will have little effect either short-term or long-term. In addition, there has been no data available since the introduction of DDT with regards the impact on humans and the environment as to its safety. What are the long term effects on humans should residue spill into drinking water etc?"

Bluntly put ... this is a stretch. There is a huge amount of research on the toxicity of DDT, though much of the research has been ignored by writers (such as Rachel Carson, the author of Silent Spring) and policy and rule makers such as the US Environmental Protection Agency especially the EPA under Ruckelhaus in the late 1970s.

In the 1950s and 1960s DDT was used in massive quantities in AGRICULTURE and it did create a growing residual in the environment which did get into the food chain and did cause a lot of concern. In spite of this, there has been only a tiny impact ... essentially none ... on human health. Though many have tried, the connection between DDT and human health deterioration seems small.

On the other hand DDT is very effective when used properly in the arsenal of weapons to combat malaria. DDT is toxic to mosquitoes, though some mosquitoes may have some resistance ... but equally important, mosquitoes do not like DDT and fly away from it (a repellant effect) and resistance to the repellant effect has not been seen.

The use of DDT as the one and only pesticide against mosquitoes would be a bad approach ... just as use of bednets or use of IRS as a single intervention is costly and ineffective. But DDT use is cost effective and when used correctly improves results enormously and quite rapidly. The experience in Kwa-Zulu Natal is a case in point and I believe that a similar strategy will be used in other parts of Southern Africa, including Zambia, in the near future.

It is interesting to note that when it comes to "toxicity", drugs like Chloriquine are more toxic to humans (mammals) than the pesticides that are used for adulticiding mosquitoes and for larviciding ... yet there is no outcry against using anti-malarial drugs.

It is also interesting to note that issues around the use of DDT constantly are being discussed, yet the potential for side effects from the use of pesticide in bednets is rarely talked about. One hypothesis is that it really does not matter, because bednets are so rarely used anyway ... (sarcasm ... the lowest form of with!).

My personal hope is that there will soon be some solid track record of performance in the global anti-malaria effort with data about costs and results collected, analyzed and available to the public at large. It is not certain that this will happen ... but there is more discussion about this now than at any time in the last 40 years.

Sincerely Peter Burgess Tr-Ac-Net and the Integrated Malaria Management Consortium (IMMC)