DDT use would save many lives in Uganda

By Prof. George B Kirya

It is most painful and very sad to see that some Ugandans feel comfortable dancing on the graves of between 200 to 300 Ugandans, mostly children and pregnant women, dying due to malaria daily, (National Malaria Control Strategic Plan 2005/6-2010/11).

These numbers are equivalent to 25 minibuses with 14 passengers each, crushing every day.

 It is even very possible that these numbers are an under-estimation of the people who actually die due to malaria in Uganda. There are those who die at home or on the way to a health facility or die in private clinics or even die while waiting for a Health Worker in a health facility and are never captured in the statistics presented.

 It is also a great shame for Uganda to be the country with the highest number of entomological infective rate (EIR) (infected mosquito bites per person), in the whole world. For example, a person in Apac district is bitten by about 1564 infected mosquitoes per annum (Uganda Malaria epidemiology and endemicity maps, National Malaria Strategic Plan 2005/6-2010/11).

People should begin asking what happened to the Scientists, the Politicians and the Community Service Organizations (CSOs) in Uganda to allow such a situation to go on unabated.

 Some of the interventions to avert the above situation have been vehemently opposed by both Ugandans and the international community even to a point of taking the Government to the Courts of Law ( Lango Co-operative Union and Seven others Vs Republic of Uganda, 2008).

This was specifically when the country wanted to use Dichloro-Dyphenyl-Trichloroethene (DDT); a cheap, long lasting, effective and long-time tested chemical of great public health in malaria control, that brought malaria to its knees in the US, Europe at the turn of the last century, and currently South Africa (South Africa Malaria reports 2004).

There is no scientist or medical person of any specialisation, anywhere in the world, who has proved or shown that the use of DDT causes liver cancer, infertility, blindness, brain disorder, and genetic defects and so on, as claimed by some Ugandans. I challenge those claimants to produce evidence to support their allegations.

 There is written evidence that during the period 1955 to 1969, DDT was used under the WHO Malaria Eradication Program covering Countries in Europe, Asian, parts of former USSR, several countries in the Middle East, the Caribbean, large areas of North and South America, including the whole of USA, Australia, Singapore and Korea.

At the end of the campaign, malaria had virtually been eradicated from all developed countries where the disease had been endemic as well as from large areas of tropical Asia and Latin America. Ironically, the meeting for the Global Malaria Eradication Campaign was held in Kampala in 1958,(World Health Assembly Reports)

 In Uganda, DDT was used in the then North Kigezi district, now known as Kanungu district and there were very successful results that enabled the then colonial government to resettle the migrants from the then densely populated Kisoro to the then heavily mosquito-infested area near the Queen Elizabeth National Park (East African Medical Journal 1963 de zellueta et al, Probing DDT and its derivatives in the residents and environment in Kihihi, Kanungu district, G.Bimenya, M.Lugemwa, W. Byarugaba 2005).

Use of DDT for mosquito control in these areas was also found to contribute significantly to the prevention of other vector-borne diseases like Leishmaniasis or Kala azar, Plague and Dengue fever

 It was also widely used by applying it on people’s hairy parts of their bodies to rid them of lice and flee infestation. As food preservative, it was used on beans, groundnuts and maize against weevils and other pests, which foods were later eaten, sometimes unwashed due to water scarcity.

Dudumaki and Safi Safi used to be common household names in Uganda in the past and were used for the above activities. These two substances, are derivatives of DDT,(Agricultural Pest Handbook; W. Igram, Department of Agriculture Uganda 1966)b

 A number of top Ugandan scientists carried out a comprehensive analysis of the environment and population impact due to DDT in Kanungu, in 2005. They interacted with men and women in their 70’s and 80’s, who were recipients of Indoor Residual Spray (IRS) with DDT in their houses. It is important to note that none of them was found suffering from any of the conditions alleged to be caused by DDT exposure, although some still had traces of DDT in their blood (Probing DDT and its derivatives in the residents and environment in Kihihi, Kanungu district, G.Bimenya, M.Lugemwa, W. Byarugaba 2005).*.

 It ought to know that there are a number of elements found in people’s bodies, which include Iron, Calcium, Potassium, Lead, to mention a few, which in reasonable quantities are vital for one’s survival; but when in large quantities can be dangerous.

It might also be said that since no harm has been established in any human being due to DDT persisting in one’s body, it might also be playing a positive role, yet to be discovered by Scientists, if we look at the situation without bias and we investigate it as scientists.

 Countries which found some problems with DDT are those which misused it by applying it massively on their farms as a pesticide. It must, however, be emphasised that no problems were found among humans

 In the USA, they were using up to 80,000 tons of DDT per year by the time it was banned. This was widely sprayed into the environment for agricultural use, with the largest quantities applied to cotton and the rest for public health. This quantity was bound to have an ecological impact.

But there is no record of any people being affected by this DDT at all, even when such big quantities were used. A revelation that eleven (11) ministers in the European Union in 2004 had substantial levels of DDT in their blood is one of the evidences to this effect.

 Uganda does not intend or wish to use DDT as an agricultural pesticide. It is going to use it only for INDOOR RESIDUAL SPRAYING (IRS), under careful control and supervision.

It is further observed that, in the past, DDT was being dissolved in highly toxic substances such as fuel oil, petroleum distillate, benzene hexachloxide or mentholated naphthalene, which will not be used this time.

 At a WHO meeting of Ministers of Health held in Johannesburg, South Africa, in 2002, it was agreed to start using DDT in accordance with the WHO recommendations, if alternative and cheaper insecticides were not available. DDT is being used in countries like Ethiopia, Malawi, Mauritius, Magdascar, Namibia, South Africa, Zambia and Zimbabwe.

 To say that there will be extensive environmental pollution arising from indoor residual spraying, is farfetched and unjustified.

 The advent of DDT use in 1930s-40s presented an opportunity for a new method of interrupting malaria transmission, by killing the mosquito at its epidemidogically most important stage, the adult, when it feeds on human beings in their dwellings and transmits malaria.

When WHO recognised that malaria was not only killing more people than any other disease but that it also interferes with the development plans, particularly in the 3rd world, that is when it began to seriously consider fighting this disease.

 It is, therefore, a great shame to see that malaria in Africa, in general, and Uganda in particular, has remained a major cause of mortality and morbidity among our nationals despite the fact that it is entirely preventable (and curable).

 Several malaria control programs that have environmental management as the central feature are available, but have a slow impact. These include bush clearing, modification of river boundaries and application of oil to stagnant water and use of mosquito screens to house windows.

 Insecticide Treated Nets (ITN) are already widely used and publicised in Uganda, as a personal (Not family or communal) protection against mosquito bites. But 80% national coverage and use are a pre-requisite for effectiveness (National Malaria Strategic Plan 2011/12-2015/16, Abuja Declaration 2000).We have seen how many Ugandans refuse to use the ITNs, even when given free, and others misuse them completely.

 Use of alternative chemicals for the dual purpose of IRS and treatment of mosquito nets has been promoted at the expense of the cost-benefit analysis of DDT.

 It has to be borne in every Ugandan’s mind that every technology used in life has some negative aspects. A good example are the medicines commonly used by many people the world over, like aspirin, penicillin, anti-cancer drugs, chloroquine, various vaccines. Even eating meat or groundnuts can be fatal to some people.

So, what is always done is to weigh all the dangers and risks of any technology against all the benefits of using it, constantly. As a result, innovations and technologies are adopted or rejected, after a cost benefit analysis has been made. This is what has been observed world-wide, as far as using DDT for malaria control, against other methods, is concerned.

Scientific studies have shown that DDT has been found best suited for the Anopheles gambiae and Anopheles fenestus mosquitoes, which two vectors are common in Uganda.

This is because of DDT’s high repellence and volatile effect on the mosquito. It is also found that 75% of mosquitoes entering a house sprayed with DDT will be repelled from the house or get so excited that biting becomes completely inhibited. No other residual insecticide has this property (G.Bimenya, M.Lugemwa Malaria vector Susceptabilty/Resistance to DDT, 2009).

 It is important to combine all the possible preventive measures, together with using vector control by applying DDT for In-door Residual Spray (IRS).

 DDT is classified as a Persistent Organic Pollutant (POP), under the Stockholm Convention, which Uganda ratified in July 2004. The Convention declared that, DDT could be produced and used only for disease vector control and according to the recommendations and guidelines, of the World Health Organisation (Stockholm Convention 2004,UNEP, WHOPES)*.

They also said that DDT would continue to be used as long as safe, effective, and affordable alternatives are not available in a country.

 Contrary to the widely circulated rumours that the European Union (EU) would abandon Uganda when it starts using DDT, there is evidence that EU supports use of DDT against Malaria in Uganda as it supports its use in South Africa, Mauritius, Namibia, Zambia and other countries (HE Borrosso, EU Vice President’s Letter to MoFA-Uganda 2008).

 The EU, in fact, recognises that DDT residues may be found in some agricultural commodities and to this end, they permit low levels of DDT contamination in some crops, so long as such levels are safe to consumers and are not due to illegal spraying of DDT as a pesticide.

 Indoor Residual Spraying of DDT should start NOW in the houses of those Ugandans who are willing and are ready, throughout the Country, even if it means cost-sharing to be able to do so; while the Government and other stakeholders continue sensitizing and also appealing to those misguided Ugandans to stop misguiding others and start appreciating the usefulness and safety of using DDT.

The author is a Professor of Medical Microbiology, former Head of the Department in the Faculty of Medicine and former Vice Chancellor of Makerere University