Can malaria be beaten?
The killer disease is back in the news. But the real story is how close we can come to eliminating its menace entirely, writes Jeremy Laurance
Thursday 05 August 2010
When I see a packet of malaria pills I think of that famous Clint Eastwood line from Dirty Harry, delivered as he pointed his .44 magnum at a bank robber and neither of them could remember how many shots he had fired, or whether there was still one left in the chamber. "The question you have got to ask yourself is: do I feel lucky? Well, do ya, punk?"
Actually, I do. Lucky enough not to have to take the nasty, expensive little things on my periodic visits to Africa and other malarial parts of the world. Now I find myself being asked to reconsider after X Factor star Cheryl Cole's unpleasant encounter with a mosquito in Tanzania. Such is the power of celebrity.
I based my view on a Lancet paper published in the 1990s by London's Hospital for Tropical Diseases which assessed the chances of contracting malaria, for those not taking prophylactic drugs, at 0.6 per cent for an average two-week holiday in East Africa. The authors described this as "high" and in public health terms I suppose it is – the Health Protection Agency points out that more than 1,500 people are diagnosed with malaria in the UK each year having acquired it abroad.
But it didn't seem high to me – and I disliked the way commercial travel clinics pushed expensive injections and other protective measures at frightened travellers without quantifying the risks. So for the last 15 years I have followed a rough rule of thumb: if I am slumming it or travelling into the bush, I take the pills; if I am staying in four-star hotels in town, I don't bother. My impression is that many regular visitors to Africa do the same. Public health doctors may demur – and Ms Cole's story undoubtedly strengthens their case. She had spent only six days in Tanzania and had, reportedly, taken anti-malarial drugs that provide 90 per cent protection. How unlucky is that?
Doubly unlucky because – and this is the real story about malaria – in many parts of the world it is declining, rapidly. About 2.5 billion people live in malarial areas around the globe, and the disease kills almost a million of them every year, mostly children. Changes in the incidence of the disease may go unnoticed by tourists but have huge significance for the local population. Now Cheryl Cole, who first visited Tanzania last year on a charity expedition to Mount Kilimanjaro, has helped focus attention on their plight in a way she could hardly have anticipated.
In coastal Kenya, not far from where she was holidaying, cases of severe malaria in children have fallen 90 per cent in the last five years. Similar falls have been reported from other locations across Africa and the world.
In certain islands in the Philippines malaria has been eliminated. Mexico is said to be close to eradication, and some countries in Central and South America are moving in the same direction. Morocco was recently declared malaria-free by the World Health Organisation, helping boost the tourist trade there.
Sub-Saharan Africa, which bears 70 per cent of the disease burden, presents a much tougher challenge. Yet even here there have been spectacular advances, as in coastal Kenya. Last week, the African Leaders Malaria Alliance announced that malaria cases and deaths had been cut by up to 80 per cent in 10 African countries since 2000, including Ethiopia, Ghana, Rwanda, Zambia and Zanzibar.
Among malaria specialists, where gloom prevailed a decade ago, the buzzword now is "elimination": no more malaria deaths by 2015 and no more malaria a decade or two after that. As the Lancet noted last month, "previously cautious malariologists, released from a 40-year collective depression... have been invigorated."
How has this change of heart come about? Some call it the Bill Gates effect. Almost three years ago, the world's biggest philanthropist threw down a challenge to the global health community to eliminate malaria in his lifetime. Sceptics responded that his dream would only be realised if he were cryo-preserved. Yet his call had a galvanising effect.
The Foundation that he leads with his wife, Melinda, has not only given grants of dizzying size to the search for a malaria vaccine, the distribution of bed nets and other measures, it has also brought a new vigour to the entire aid industry. Its speed and flexibility leaves larger bureaucracies like the UN standing, and where it goes others follow. It has been described as a new type of multilateral organisation, introducing entrepreneurial flair to a sector submerged in red tape.
Some complain that Gates is seeking to replicate the world domination he achieved with Microsoft in another, albeit altruistic, sphere. These critics say the new entrepreneurial aid business he has spawned is undemocratic, overly powerful, and is leading to empire- building, wasteful competition, fragmentation and duplication. Why should Bill Gates decide which sorts of vaccines get developed? they ask.
There is no denying, however, the impact of Gates's interest on the bottom line. Today's funding for malaria, from all sources, exceeds $10bn (£6.3bn) – a hundredfold increase in little more than a decade. Celebrities from Senegalese musician Youssou N'Dour to David Beckham have joined the cause. Politicians Bill Clinton and Tony Blair have become involved through their respective aid foundations, followed by a growing queue of corporate donors and public figures who bring clout, profile and funding. This week, Andrew Mitchell, the International Development Secretary, published the UK's business plan for malaria, opening a consultation on the best ways of supporting the fight against the disease.
Malaria – for so long the poor relation to Aids in terms of global attention, despite claiming more lives in many countries – is suddenly glamorous.
The tools for elimination are to hand. More than 200m insecticide-treated bed nets have been distributed since 2000, and are estimated to have saved 1m lives, according to the Roll Back Malaria Partnership. Ban ki-Moon, the UN Secretary General, said that with the delivery of a further 150m bed nets by the end of this year "universal coverage of malaria prevention can be achieved". Vast funds have been invested in indoor spraying against mosquitoes, in distributing more effective artemesinin-based drugs against the disease, and in developing a vaccine, with one candidate, made by the UK-based pharmaceutical manufacturer GlaxoSmithKline, in final (phase III) human trials.
But meeting Gates's challenge will be a tough task. Optimists, such as Sir Richard Feachem of the Malaria Elimination Group, point to the "shrinking map" of malaria, which included the US and the UK in 1900 (when malaria was endemic in the Kent marshes). Today, 108 countries in the world are malaria-free. One hundred countries have continuing malaria transmission, and of these, 39 are embarked upon malaria elimination. The remaining 61 are striving to control malaria, but it is Feachem's hope that they too can be persuaded to switch to a policy of elimination.
The task is immense. In 2008, malaria killed 863,000 people. Almost 90 per cent of those who died were in Africa, and of those, almost 90 per cent were children under five, according to the WHO. Children are especially vulnerable because they have undeveloped immune systems; the WHO estimates the disease kills 3,000 children a day.
The world has been striving to eliminate malaria for more than half a century – with faint success. The Global Malaria Eradication Programme was launched in 1955 but it quickly became apparent that its ambition was not achievable in sub-Saharan Africa. In the late Sixties the strategy switched from eradication to long-term control; people with fever caused by the disease were treated with the then standard drug, chloroquine. But as resistance to the drug grew, malaria deaths rose through the 1970s and 1980s. By the early 1990s the strategy was recognised as a disaster.
Throughout the 1990s, as nations wrung their hands over Aids, efforts were made to refocus attention on malaria. The world's health ministers launched a global declaration in Amsterdam in 1992 to control the disease, with a focus on Africa. The latest drive against the disease began 10 years ago, when leaders of countries across Africa signed a declaration in Abuja, Nigeria to "halve the malaria mortality for Africa's people by 2010". Initially progress was slow; there were reports that instead of declining, malaria was rising, by up to half in some areas. Accurate figures were hard to come by, and estimates were distrusted. What is not in dispute, however, is that over the last three years things have moved much more quickly, and more consistently in the right direction. The huge rise in the importation of bed nets and artemesinin drugs has saved millions of lives.
Controlling malaria has come to be seen as good business, not just good charity. The disease is estimated to cost Africa $12bn a year – 1.3 per cent of its economic growth. If that sum could be saved, it would constitute the biggest boost to health and development in the continent's history. Eradicating disease boosts productivity, creates markets and stabilises governments.
The future, however, is anything but certain. Though the 90 per cent fall in children with severe malaria on the Kenyan coast is impressive, the reasons are not obvious. Malaria has been in decline in this area for at least 15 years and some have suggested climate change is a factor. Meanwhile it is rising in upland areas around Mount Kenya, where incidence was previously low. Professor Robert Snow, who reported the Kenyan figures in The Lancet, said malaria had changed "from a major cause of childhood illness and death to a relatively minor problem" on Kenya's coast. But it was simplistic to attribute it to more bed nets and better drugs. "The truth is probably much more complex," he wrote.
Critics also question the notion of "universal coverage" with bed nets – expected in Ethiopia and southern Sudan this year and everywhere in early 2011. How many nets can you hang in a small hut occupied by a large family? Some older children are always likely to go without. There have been distribution problems too: the rush to freight in bed nets has left thousands of them sitting in warehouses because there was no means of transporting them over the final miles.
Malaria is concentrated around the equator, the "middle, wet bit" of Africa, with just seven countries accounting for two thirds of all cases: the Democratic Republic of Congo, Ethiopia, Kenya, Nigeria, southern Sudan, Tanzania and Uganda. While there have been gains in some, others such as Nigeria have done less well. With a population of 120 million, Nigeria contributes heavily to the global malaria burden.
Even where success has been achieved, there is no guarantee it will be permanent. Zanzibar, the island off Tanzania that has become a luxury tourist destination, has eliminated malaria twice before but each time it has been re-imported from the mainland. Kenya has also slipped back, and in Congo the uncertainties multiply.
Constant vigilance is essential. That requires stable, committed government. It is not always available. In Uganda, grants worth over $350m were suspended by the Global Fund over allegations of corruption (which are currently before the courts). In Tanzania a grant worth over $100m from the Global Fund was discovered unclaimed last year because it lacked a single signature.
Countries worst affected by the disease have been reluctant to buy the new artemesinin-based drugs because of their cost. At $1 to $2 a dose, they are 10 times more expensive than chloroquine. Though funded by aid programmes today, governments wonder for how long that funding will last. There are fears about resistance too, signs of which have emerged on the Thai-Cambodian border. If the artemesinin drugs lose their potency, there is nothing else immediately in the pharmaceutical locker.
Eradication may be the only way to combat resistance. The most taxing question, however, and one which divides the malaria community, is what penalties may follow success? Chris Drakeley, director of the Malaria Centre at the London School of Hygiene and Tropical Medicine, points out that enormous funds are required to eliminate the last few cases of a disease – witness polio, still defying efforts to wipe it from the planet.
"If malaria drops down the Top 10 list of worst diseases, what justification is there for putting in vast resources to eliminate it? In a situation where malaria had been controlled to a low level for a decade, you would have a large group of children with no immunity to the disease. The impact of an outbreak could then be devastating. There is an argument that some level of malaria is quite good – it maintains a level of immunity in the population."
The best hope for the future is a vaccine. No disease has ever been eliminated without a vaccine. But malaria is not caused by a simple virus – it is an organism (a parasite) with a nucleus that is more complex than a virus.
The front runner is GlaxoSmithKline's RTSS vaccine, currently being tested in 14,000 children in 11 African countries, with results due in 2012. Early trials suggested that it provided 30-50 per cent protection – far from perfect, but a lot better than nothing.
Scientists are optimistic that it will provide a useful further weapon against malaria. But there will be many years yet of fighting before the war can be declared won.
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