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Tackling Malaria: Time to Rethink DDT?

The Institute of Medical Research, in Lagos.

Chief Research Fellow, Dr Sam Awolola.

Student doctor assists in Malaria research.

Adult mosquitos bred in the labs.

Mosquito larvae produced.

Student doctors assist in other research at the institute, here research into the AIDS virus.

A researcher works on HIV/AIDS.

Think Africa Press reports from Nigeria on malaria, a disease which kills a million every year while a key weapon against it is held back by Western countries.
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Lagos, Nigeria:

April 25 was World Malaria Day, an annual marker instituted in 2007 to recognise the global effort to control a disease which predates humanity and still kills more than 1 million people a year. Malaria remains overwhelmingly a plague of the poor, and the use of DDT, the most potent weapon against it, is hampered by wealthy countries spurred on by the environmental lobby.

Malaria continues to claim 85% of its victims in sub-Saharan Africa, “the heartland of malaria” from where the disease originates, and its victims are mostly children. Nigeria alone accounts for 25% of African deaths. Malaria is the leading cause of death in children under 5-years-old in Nigeria, and it causes about 11% and 70% of deaths in pregnancy and maternal anemia respectively.

Although for many years a drop-off in the high malaria death rate was elusive, in 2009 it became clear that progress was being made: malaria-related deaths fell from 985,000 in 2000 to 781,000 in 2009, while over the same time period in 11 African countries the malaria burden dropped by more than 50%. These figures have aroused such hope that the WHO now believes the possibility of ending all deaths from malaria by 2015 is “within reach”. However, the WHO is keen to assert that gains made are “fragile” and dependent upon a continuous flow of resources, good governance and effective partnerships.

Path to success?

Dr Luis Gomes Sambo, WHO Regional Director for Africa, praises the efforts made by malaria-endemic countries and partners in accelerating and sustaining malaria prevention and control in the region. Critically, malaria, both a cause and consequence of poverty, has been brought into national poverty reduction strategies, while there is now a higher success rate for proposals submitted to the Global Fund

“Consequently,” says Dr Gomes Sambo, “effective interventions including protection from the mosquito vector through the use of Insecticide Treated Nets (ITNs) and Indoor Residual Spaying (IRS), prompt treatment of malaria cases using Artemisinin-based combination therapy (ACT), intermittent preventive treatment of malaria in pregnant women (IPTp) and infants (IPTi) are being adapted and scaled up.

“Cross-border initiatives are catalyzing efforts to accelerate and sustain control and, where possible, to prepare for the transition to pre-elimination. The Affordable Medicines Facility for Malaria (AMFm) has been launched in Ghana, Kenya, Madagascar, Niger, Nigeria, United Republic of Tanzania and Ugandato ensure access to quality ACTs in private sector facilities. Malaria vaccine trials are ongoing in Burkina Faso, Ghana, Gabon, Malawi, Mozambique, Tanzania and Kenya.”

WHO Director-General Margaret Chan attributes the improvement to a combination of commitment from African leaders, financial support from donor countries and institutions, and good leadership and co-operation from the more than 500 members of the Roll Back Malaria Partnership.

‘Fragile gains’

In spite of the proclamations of progress, it is hard to mainatin a wholly sanguine outlook on future efforts against malaria. While reaching the optimisitic 2015 elimination target will require the continuation and expansion of funding from states and partners, the appearence of drug resistent malaria parasites or insecticide resitant mosquitos could reverse any recent successes.

There are already fears of a spread of resistance to some key drugs used to combat malaria. The reported development of resistance to artemisinin – which still retains effectiveness when used with a partner drug in a combination therapy - in the Mekong area of Southeast Asia is, the WHO believes, likely to spread to Africa. Insecticide-treated bednets are a crucial weapon against malaria – Nigeria’s disbursement of 71 million treated bednets has been credited as one of the “tremendous strides” in malaria control - but classes of insecticide are limited, and the immensly expensive task of creating new insecticide classes is unlikely to be undertaken by chemical companies unable to gain profit through a non-existent market or by malaria-endemic countries lacking in resources.

Wider funding of healthcare across states is also of critical importance. With many countries failing to meet pledges made under the Abuja Declaration, the improvement of rural healthcare provision remain threatened. As a Nigerian malaria specialist who did not want to be named told Think Africa Press, the issue of attitudes to malaria in rural communities is a key factor in eradicating of the disease.

“We can end Malaria by 2015, but it will require a high amount of resources,” she said. “We must reduce transmission through two years of residual spraying of houses and the use of rapid test kits – some people with a fever are being treated for malaria, which wastes resources.

“Then there is the problem of how people see malaria. People in Nigeria will say, ‘Oh, this year I haven’t had malaria’. They think it’s something they should have. As a consequence, health-seeking behaviour is very poor.”

Cause and consequence

Malaria’s symbiotic relationship to poverty is clear. Harvard University and the London School of Hygiene and Tropical Medicine assert that Malaria plays "a significant role" in the poor economic performance of disease-endemic countries.

In such states, malaria is thought to be responsible for a 1.3% ‘growth penalty’ every year, which over a 15-year period amounts to losing about a fifth of gross national product. On a yearly basis, it is estimated that across Africa $12 billion is lost from gross domestic product every year due to malaria. And these losses are compounded by the plethora of ‘short-run’ costs – such as prevention and treatment costs and lost work time – caused by the disease, alongside losses to the tourism industry and from businesses avoiding disease-endemic areas where a reliable workforce is in short supply.

Thus, for such countries malaria is a key stumbling block in achieving sustainable economic development, and its eradication would result in an immediate economic boost. But to achieve this, significant resources must be committed at the state level. These resources, coupled with international funding, must be used to enable effective monitoring and evaluation, the provision of rural healthcare facilities and programmes to provide education on the prevention and treatment of malaria and clearly targeted and structured programmes involving countries and partner stakeholders. And if private chemical companies can find no economic rationale for the expensive research and development needed to create new insecticides, the state must assist in creating the market.

On the frontline

At The Nigerian Institute of Medical Research, in Lagos, the vital research into combating malaria and other diseases is undertaken every day. The centre is the oldest health research institute in the country, drawing a lineage back to the 1920s when medical teams arrived in the area to begin work on Yellow Fever.

Alongside malaria, the Institute’s priorities include HIV/AIDS, tuberculosis and neglected tropical diseases such as schistosomiasis, which is relatively unknown to the layman but second only to malaria in terms of public health importance for tropical diseases in Nigeria.

Dr Sam Awolola, chief research fellow at the Institute, told Think Africa Press that of the four classes of insecticide used against malaria, resistance is being reported in all of them. Dr Awolola is unequivocal on the chance of developing new insecticides.

“There’s no chance of developing new insecticides – it’s not lucrative when compared to agricultural insecticides,” he says.  “It would cost millions of dollars and would take many years and lots of investment. This is beyond what disease-endemic countries can do.

“We need a strategy to manage resistance, and one is to rotate different classes of insecticide in house spraying.”

The controversial cure

In a fight against malaria which is impaired by a limited range of effective insecticides and the potential for resistance, there remains one tool which has been hugely successful in combating malaria yet which draws immense controversy over the impact it has on humans and the environment: dichlorodiphenyltrichloroethane, more commonly known as DDT.

The creator of the pesticide won a Nobel Prize in the 1940s, where after it was used to finally stamp out malaria in the USA and Europe, to control typhus and extensively as an agricultural insecticide. In the 1960s a backlash began against DDT after the publication of the seminal environmental movement book ‘Silent Spring’, which outlined the impact of unrestricted DDT use on the environment, wildlife and humans. Crucial to the environmental lobby’s opposition to DDT, which has a half-life that can exceed ten years, is the ‘persistent organic pollutant’s’ resistance to soil degradation, its ability to accumulate in the fat of animals and humans, and its link to breast cancer.

DDT was subsequently banned for use in agriculture by the USA and other countries. By the 1990s there were growing calls to introduce a worldwide ban, which came into force in 2004 in the form of a worldwide treaty. While exemptions were made which permit limited use of DDT in indoor spraying for fighting vector-borne diseases, procuring DDT became increasingly difficult.

In 1999, 371 of the world’s leading experts on malaria – including three Nobel laureates - signed a letter warning of the consequences of banning DDT. Amir Attaran, then director of the Malaria Project in Washington said: "If Western countries like the US or UKwant the environmental benefit of a DDT ban, let them pay for it. Africa, Asia and South America have neither the technology nor money to research and implement alternatives to DDT. The rich countries do. For them to advocate a DDT ban while holding tight the purse-strings for those alternatives is obscene."

Many malaria specialists argue that at the heart of a misunderstanding of DDT is the conflation of the negative impacts that result from DDT’s historical, widespread agricultural use with the comparatively limited amounts needed for spraying of rooms for malaria, for which there is no evidence that humans, animals or the environment would be detrimentally affected. And, in this respect, while the scientific evidence that supports the withdrawal of DDT seems inconclusive, its impact in fighting malaria is unquestionable. It is highly effective at repelling mosquitoes for long periods of time and has the longest ‘residual efficacy’ of any insecticide. And while mosquitos can develop resistance to DDT they avoid sprayed rooms.

The WHO has wavered on DDT, going from condemning the use of the chemical to, in 2006, re-affirming its utility in fighting malaria, before joining the United Nations Environment Programme in 2009 in saying that it wants to “achieve a 30% cut in the application of DDT worldwide by 2014 and its total phase-out by the early 2020s, if not sooner". A 2007 WHO position statement  stated that “DDT is still needed and used for disease vector control simply because there is no alternative of both equivalent efficacy and operational feasibility, especially for high-transmission areas”. A critic of the WHO about-face said it “has nothing to do with science or health and everything to do with bending to the will of well-placed environmentalists".

There is intense hypocrisy in the politics surrounding DDT: it was used in Europe and the USA to help in finally eradicating malaria, while in India, Sri Lanka and South Africa, among many others, it was hugely effective in combating tens of millions of cases before its withdrawal led to resurgences in malaria.

The main opposition today comes from the European Union and Switzerland. African states are largely in favour of using DDT, India maintains a diplomatically expressed approval, the USA is neutral, while China abstains from the debate. The fear remains in African nations that the EU could block food exports if crops have even miniscule traces of DDT. Arata Kochi, the former WHO malaria programme director who led the drive to support DDT use, said that Uganda’s failure to use DDT was due to “a bureaucratic standoff between the ministry of health and the ministry that oversees trade”.

The poorest are sacrificed

The view expressed by Greenpeace that there is a reliance on DDT as a “silver bullet” dismisses the work done across the world in combating malaria without DDT. And the application of the risk-based ‘precautionary principle’ - placing the burden of proof of DDT’s safety on those who want to use it – to DDT obviates that while increasing some risks, DDT greatly lessens others.

That it is Western countries devoid of malaria leading the campaign against the targeted use of a chemical that would have an immediate impact on the health and wealth of many poor countries on the basis that it could cause harm smacks of another case where the lives of millions of the world’s poorest are sacrificed against the alter of unsubstantiated environmentalism. As a leading malaria researcher asserts, since the DDT ban came into force, it "may have killed 20 million children”. It is surely time to rethink the targeted use of DDT in some of the worlds poorest countries without allowing the debate to be controlled by lobby groups based in the richest.

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