Pesticides are substances intended to prevent, destroy, or repel pests. Although most are synthetic chemicals, some are plant derivatives, inorganic dusts, or biological agents/products such as bacteria or their toxins. The term "pesticide" is usually further subdivided into more specific terms such as: fungicide (kills fungus), herbicide (kills plants), acaricide (kills mites and ticks), avicide (kills birds), insecticide (kills insects), etc.

DDT was developed as the first of the modern insecticides early in World War II. It was initially used with great effect to combat malaria, typhus, yellow fever and dengue fever plus other insect-borne human diseases among both military and civilian populations.

Therefore the use of small amounts of DDT means the difference between life and death for thousands of people in the developing world today.

Effectiveness of DDT in malaria control

Europe and North America have not harbored malarial mosquitoes since the 1940s. In one of the most miraculous public health developments in history, Greece saw malaria cases drop from 1-2 million cases a year to close to zero, thanks to DDT. Meanwhile, in India, malaria deaths went from nearly a million in 1945 to only a few thousand in 1960. In what is now Sri Lanka, malaria cases went from 2,800,000 in 1948, before the introduction of DDT, down to 17 in 1964 - and then, tragically, back up to 2,500,000 by 1969, five years after DDT use was discontinued there. In South Africa malaria cases increased 10-fold in the late 90s but dropped 80% in 2000 alone in KwaZulu Natal, the one province that made extensive use of DDT. In Madagascar, malaria incidence declined more than 90% after just two annual spray cycles.

When DDT was sprayed on house walls (2g of DDT/m2 of wall surface every 6 months) it exerted powerful control over indoor transmission of malaria. It is an astonishing fact that WHO guidance for spraying houses is the same today as it was in the eradication era 50years ago. Perhaps 100 million lives have been saved because of DDT's success in eradicating malaria, yet some interests now think of it largely as one of those nasty chemicals that need to be banned.

Campaign of misinformation and the Ban of DDT

In her 1962 book "Silent Spring," Rachel Carson chronicled DDT's poisonous effects, showing, for example, how it killed the robins that ate the earthworms that dined on the leaves of Dutch elm trees that had been sprayed with the insecticide. The public outcry was tremendous. The book led to the establishment of the Environmental Protection Agency (EPA) in 1970 in the United States. EPA then convened scientific hearings and appointed a Hearings examiner, Edmund Sweeney. After 9000 pages of testimony from all camps of opinion, Sweeney concluded that, "DDT is not carcinogenic, mutagenic, or teratogenic to man [and] these uses of DDT do not have a deleterious effect on fish, birds, wildlife, or estuarine organisms." Every major scientific organisation in the world supported DDT use. Surprisingly two months later, on June l4, l972, the Environmental Protection Agency's first administrator, William Ruckelshaus, ignored the advice of his scientific advisors and announced a ban on virtually all domestic uses of the pesticide DDT. He later admitted that he made the decision for "political" reasons. "Science, along with economics, has a role to play . .. .. [but] the ultimate decision remains political," Ruckelshaus said. This was done despite the fact that DDT had earlier been hailed as a "miracle" chemical that repelled and killed mosquitoes that carry malaria.

No DDT-related human fatalities or chronic illnesses have ever been recorded, even among the DDT-soaked workers in anti-malarial programmes or among prisoners who were fed DDT as volunteer test subjects - let alone among the 600 million to 1 billion who lived in repeatedly-sprayed dwellings at the height of the substance's use.

The only recorded cases of DDT poisoning were from massive accidental or suicidal ingestions, and even in these cases, it was probably the kerosene solvent rather than the DDT itself that caused illness.

Dr Norman Moore, the British scientist who first claimed that DDT might be the cause of declining eagle populations (one of the chief non-human-health arguments for eliminating the chemical), conceded that the pesticide's huge benefits might easily outweigh its purported effects on animals: "If I were living in a hut in Africa," mused Moore, "I would rather have a trace of DDT in my body than die of malaria." In the late 1970's, Dr Roberts, a medical zoologist, travelled to Brazil to conduct experiments in malaria control. He built two houses and sprayed the inside of one with DDT. Hundreds of mosquitoes entered the unsprayed house, he said. None entered the sprayed house. Since then, Dr Roberts has become an ardent defender of DDT. "We have got to stop pressuring countries to stop using DDT. It is immoral", he said.

To put it more succinctly, one could say "criminal" instead of "immoral" particularly in this era of multi-drug resistant malaria. It is interesting to note that when malaria-carrying anopheles mosquito was annihilated in Europe and North America, then and only then did DDT become too toxic for the environment. What a sham!The anopheles mosquito delayed the colonisation of inland Africa. What an irony that one hundred years on, the same insect is delaying the modernisation of our economies! The only difference is that today the insect is aided along by misinformed armchair campaigners for environmental protection.

They prefer to line their pockets with travel allowances as they hop from conference to conference than protect the lives and economies of their fellow countrymen. Somewhere in the world (including Uganda) one child dies every 12 seconds around the clock because of malaria. Some 300 million people a year are debilitated by malaria, at immense cost to both human health and the economies of poor nations like Uganda. Alternative pesticides, e.g. malathion have been proposed instead of DDT. However, based on statistics compiled in 1978, costs of chemicals for protecting a person showed malathion to be five times more expensive than DDT.

A study of DDT alternatives for malaria control in Ecuador showed that the cost of other insecticides was many times higher than the cost of $1.44 to spray one house per year with DDT. Generally, the cost of treating one house with DDT ranges from $1.60 to $8.50, compared with $4.20 to $24 for pyrethroids. High costs and downward trends in foreign aid suggest that many countries (read Uganda) cannot afford the switch to DDT alternatives. DDT is the most cost-effective chemical we have for the prevention of malaria.

USA aid is contingent on not using substances that are banned in the USA. We are threatened with sanctions against our agricultural and fish exports if we go ahead and protect our people with DDT. It is the epitome of injustice that the current USA law explicitly allows use of DDT in the USA in the event of a public health emergency (e.g. malaria outbreak), but this exception is not extended to poor countries like Uganda! If the mass massacre of our innocent children is not an emergency, then what is?

Who is preventing DDT use?

Despite the cost in human lives, many groups stubbornly defend the ban. While the World Health Organisation, the National Academy of Sciences, and UNICEF have recommended continued DDT use, influential organisations such as the Norwegian Development Agency, the Swedish International Development Agency, the Swedish Aid Agency, and USAID - the sorts of groups from whom some poor nations such as Uganda receive the majority of their public health money - continue to insist that DDT be left out of malaria-control efforts.

Secondly, it is public knowledge that Pharmaceutical companies, which are based in these developed countries, own patents and are the manufacturers of anti-malarial drugs. They stand to lose a lot of money if malaria was to be wiped off the face of the earth. It is worth noting that these Pharmaceutical companies are very rich - richer than say all airline companies in the world put together- and they have a powerful lobby in corridors of power in the West. Could they have a hand in this ban? Perhaps the real truth will never be known.

Thirdly, DDT had dramatically cut the death rates in the developing countries, and thus increased population growth. This was and is still viewed by some interest groups as undesirable as it increases competition for the limited world resources. For instance when USAID discontinued its support for DDT spraying, it increased funding for birth control programs!

Due to the ban, it is no longer easy to get a reliable supply of DDT on the world market. Only three countries - China, India and The Russian Federation - are manufacturing DDT. Recently, India received a hefty sum of money from the World Bank to lure it to abandon the manufacture and use of DDT in its public health programs. What a shame!

I'd rather die of DDT (and no one has) in say 20 years time than die of multi-drug resistant malaria today. The lives of millions of Ugandans in our malaria-endemic country should be given priority over the welfare of birds. What is the environment for to a dead man? A Runyankore saying, Ery'omuntu ritungamira ery'ente, means that a human being is more important and should be valued more than a cow - and definitely more than a robin.

DDT should be produced and distributed under regulated conditions for the government to use in malaria control only. Use of this insecticide should not be banned until the benefits and costs of its controlled use are weighed against the benefits and costs of other interventions including doing nothing. The science is unequivocal about the cost effectiveness of DDT in malarial control. The banning of DDT was purely for political reasons. Therefore the resumption of its use can only be politically decided.

The writer holds a PhD(UK) in Chemistry, an MSc(UK) in Health Economics and Health Policy and a Postgraduate Cert(UK) in Health Care management.

ALLAFRICA.COM