MALARIA: History: War and Malaria

14 April 2011
Today marks the 150th anniversary of the start of the US Civil War. The most common number of deaths attributed to that war is 620,000, a number that surpasses mortality in all other US wars from independence to Vietnam. Ironically two-thirds of these deaths were from disease.
Reports have it that, ” Surgeons from both sides of the Civil War called malaria “ague”,”shakes”, or “intermittent fever”; the illness accounted for 20 percent of all sickness during the war.” This was at a time when people believed that, “… malaria was caused by poisonous vapors emanating from ponds and swamps. While many of the men noted in their diaries the swarms of mosquitoes that attacked during warmer months, and the ensuing sickness that enveloped the camp, they never put the two together.”
Concerning mortality, it was estimated that malaria was responsible for three out of five Federal casualties and two out of three Confederates during the US Civil War. Of course during thie period malaria was commonly misdiagnosed, but “it is estimated that malaria was responsible for killing a full quarter of all servicemen during this time.”
http://www.malariafreefuture.org/blog/?p=1190

MALARIA: History: The University of Chicago Malaria Experiments on Prisoners at Stateville Penitentiary

Bernard E. Harcourt : University of Chicago - Law School : February 6, 2011


In March 1944, doctors at the University of Chicago began infecting volunteer convicts at Stateville Prison with a virulent strand of malaria to test the effectiveness and side-effects of potent anti-malarial drugs. According to Dr. Alf Alving, the principal investigator, malaria "was the number-one medical problem of the war in the Pacific" and "we were losing far more men to malaria than to enemy bullets." http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1758829

MALARIA: The first Finnish malariologist, Johan Haartman,

The first Finnish malariologist, Johan Haartman, and the discussion about malaria in 18th century Turku, Finland


Hulden L
After the Great Northern War in 1721, Sweden ceased to be an important military power. Instead, the kingdom concentrated on developing science. Swedish research got international fame with names as Carolus Linnaeus, Pehr Wargentin and Anders Celsius. Medical research remained limited and malaria was common especially in the coastal area and along the shores of the big lakes. Already in the beginning of the 18th century Swedish physicians recommended Peruvian bark as medication and they also emphasized that bleeding or blood-letting a malaria patient was harmful. Although malaria was a common disease in the kingdom, the situation was worst in the SW-part of Finland which consisted of the town of Turku and a large archipelago in the Baltic. The farmers had no opportunity to get modern healthcare until Johan Haartman was appointed district physician in 1754. To improve the situation he wrote a medical handbook intended for both the farmers and for persons of rank. Haartman's work was first published 1759 and he discussed all the different cures and medications. His aim was to recommend the best ones and warn against the harmful. His first choice was Peruvian bark, but he knew that the farmers could not afford it. Haartman was appointed professor in medicine at the Royal Academy of Turku in 1765. The malaria situation in Finland grew worse in the 1770's and Haartman analysed the situation. He found the connection between the warm summers and the spring epidemics next year. In a later thesis, Haartman analysed the late summer/early autumn malaria epidemics in the archipelago. Althouh Haartman did not know the connection between malaria and the vector, he gave astute advice and encouraged the farmers to build their cottages in windy places away from the shallow bays in which the Anopheles females hatched. Haartman died in 1788. After his death malaria research in Turku declined. His medical handbook would not be replaced until 1844.

Malaria Journal 2011, 10:43 (15 February 2011)

MALARIA: Award-winning malaria scientist warns of drug resistance

CARLY WEEKS
 Oct. 25, 2010
The most effective malaria treatment ever discovered was not developed by a team of scientists in a high-tech lab. It was created using a traditional Chinese herbal remedy that had been used to treat illness for hundreds of years.



The treatment is made using a compound, artemisinin, isolated from a herb used in traditional Chinese medicine. It is 95 per cent effective at curing malaria, according to the World Health Organization.
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But Nicholas White, one of the scientists who pioneered the development of artemisinin-based malaria therapies, is warning that growing parasite resistance to the treatment, spurred in large part by the massive marketing of counterfeit versions, could have major consequences down the road – perhaps even making the drug ineffective.
Malaria is caused by a parasite, which is spread to humans by infected mosquitoes. It causes a variety of symptoms, including fever and chills, and can progress to more serious illness or death.
Dr. White, director of Mahidol Oxford Tropical Medicine Research at Mahidol University in Bangkok and one of the world’s leading malaria experts, is being honoured in Toronto this week as winner of the 2010 Canada Gairdner Global Health Award, given to those who have made major scientific advances in the developing world.
Six other individuals, including one Canadian, will also receive awards for their contributions to medicine and science at an awards gala in Toronto on Thursday. The Canada Gairdner award, one of the world’s most prestigious medical honours, has developed a reputation for early recognition of future Nobel prize winners.
Dr. White said he first came across the use of artemisinin to treat malaria in a small Chinese journal in 1981. The treatment had been used there for years,and appeared to be safe and effective, he said.
It was a major breakthrough, since drugs that were commonly prescribed to treat malaria at the time failed to work in many people, largely because of parasite resistance.
“[It was] almost too good to be true,” Dr. White said in an interview.
But after years of trying to convince the international health bureaucracy of how important artemisinin-based therapies could be, Dr. White said he continued to face resistance from officials who felt the treatment hadn’t been studied well enough.
“Although there was a lot of evidence the drug worked, no one was recommending them or using them,” Dr. White said.
His team launched its own trials to try to prove how well the drug worked, and what a difference it could make in the fight against malaria, which kills at least a million people around the world every year.
Amir Attaran, who holds a Canada Research Chair in Law, Population Health and Global Development Policy at the University of Ottawa, was one of the advocates who pressed Dr. White’s case for wide acceptance of artemisinin-based malaria therapies.
Eventually, after years of work and political fighting, the World Health Organization began recommending a few years ago that artemisinin drugs should be the first line of treatment for malaria, so long as it was used in combination with other anti-malarial drugs.
It’s an important caveat. Evidence shows that resistance to artemisinin treatments, when they are given on their own, is rising because the drugs weaken the parasite but don’t kill it. Combining treatment with other anti-malarial drugs cures about 95 per cent of cases and dramatically reduces the risk of drug resistance.
The WHO’s recommendations might not mean much, however, unless something is done to curb the market for counterfeit artemisinin drugs. These often contain small amounts of artemisinin – not enough to treat the malaria, but enough for the bug to develop resistance. Furthermore, people who take counterfeit artemisinin don’t take the recommended combination of other anti-malarial drugs, which also greatly increases the chance of drug resistance.
It’s a major problem that could threaten the future effectiveness of artemisinin-based therapies, Dr. White said.
“We have no idea what the real true proportion of counterfeits are, but some people say up to half are fake.”
Programs have been put in place to subsidize the cost of the drug and make them widely available for a lower cost, which should help eliminate the black market for counterfeit drugs, Dr. White said.
It is still an uphill battle, and one that needs much more support from wealthy, developed countries such as Canada, he added. But his achievements, set in motion by Chinese researchers who recognized the importance of an ancient herbal remedy, mean the eradication of malaria is once again a possibility.
http://www.theglobeandmail.com/life/health/award-winning-malaria-scientist-warns-of-drug-resistance/article1771762/

MALARIA: Malarial mosquitoes helped defeat British in battle that ended Revolutionary War

J.R. McNeill, October 18, 2010
Major combat operations in the American Revolution ended 229 years ago on Oct. 19, at Yorktown. For that we can thank the fortitude of American forces under George Washington, the siegecraft of French troops of Gen. Jean-Baptiste Donatien de Vimeur, the count of Rochambeau - and the relentless bloodthirstiness of female Anopheles quadrimaculatus mosquitoes.
Those tiny amazons conducted covert biological warfare against the British army. Female mosquitoes seek mammalian blood to provide the proteins they need to make eggs. No blood meal, no reproduction. It makes them bold and determined to bite.
Some anopheles mosquitoes carry the malaria parasite, which they can inject into human bloodstreams when taking their meals. In eastern North America, A. quadrimaculatus was the sole important malaria vector. It carried malaria from person to person, and susceptible humans carried it from mosquito to mosquito. In the 18th century, no one suspected that mosquitoes carried diseases.
Malaria, still one of the most deadly infectious diseases in the world, was a widespread scourge in North America until little more than a century ago. The only people resistant to it were either those of African descent - many of whom had inherited genetic traits that blocked malaria from doing its worst - or folks who had already been infected many times, acquiring resistance the hard way. In general, the more bouts you survive, the more resistant you are.
Malaria was all over the American South but especially prevalent in the warm, humid coastlands from Georgia to Maryland, where the climate suited mosquitoes and there were plenty of people (and other mammals) to bite.
In 1779 the British chose a "southern strategy" in their war against rebellious Americans. Since 1775, they had fought inconclusively, with the British controlling the main ports but unable to hold the countryside. To break the deadlock, they sent an army of 9,000 men, British and German (known as Hessians to the Americans) to besiege Charleston, S.C. A few victories in the South, they hoped, would inflame Southerners loyal to King George III, causing them to rise up and allow London to "Americanize" the war.
But in the South, A. quadrimaculatus were more numerous and more determined than Loyalists. South Carolina's irrigated rice plantation economy had made good mosquito country better by creating excellent breeding habitat. Every summer, hungry mosquitoes injected malaria parasites many times into almost everyone in the Lowcountry. As one German visitor put it, "Carolina in the spring is a paradise, in the summer a hell and in the autumn a hospital." The death rates, especially among small children, spiked every year from August to October as a result of malaria. Those who survived to adulthood were highly resistant.
The British army, commanded by Gen. Charles Cornwallis, consisted of lads from Britain and Germany. Very few had grown up with malaria. Most were highly susceptible. Cornwallis's army, although a superior fighting force, suffered from a malaria-resistance gap.
Eating spiders
Doctors and medicine were little help. To treat malaria, military physicians normally recommended venesection - draining 20 ounces of blood, about 10 percent of an adult's supply - sometimes supplementing that with doses of mercury or opium, and in one case applying freshly killed pigeons to the soles of patients' feet.
Fortunately, doctors were almost as scarce as hen's teeth. On their own, soldiers could try English folk remedies for ague (as malaria was known) such as eating cobwebs and spiders, drinking one's urine or tying one's hair to a tree trunk and yanking one's head so violently as to leave their hair - and illness - with the tree. These measures did no good but surely did less harm than venesection or a swig of mercury.
Only one thing 18th-century doctors prescribed against malaria did any good: bark. Powdered bark from the cinchona tree, found only on the eastern slopes of the Peruvian Andes, contained alkaloids that checked malaria. But the bark was expensive, and by 1779 it was increasingly hard for the British to get: Spain controlled the supply and had entered the war against Britain. The bark was a strategic good.
Cornwallis's army won most of its battles but suffered heavily from malaria in the summer and fall of 1780. After recovering their health in the winter, the British fled the Carolinas in April 1781 for Virginia, a move that Cornwallis believed might allow him to "preserve the troops from the fatal sickness, which so nearly ruined the Army last autumn."
He headed for healthier upland regions, but his commander in New York ordered him to the Tidewater - malaria country. Cornwallis objected, wondering about the logic of occupying a "sickly defensive post in this Bay." But orders were orders, so Cornwallis started to dig in around Yorktown in midsummer.
A speedy surrender
By late September he was besieged by a Franco-American army, recently arrived from New York and New England. After 21 days, Cornwallis surrendered a quarter of the British forces in North America, quashing British hopes in the war. A British fleet arrived five days later - too late. Cornwallis explained to his superiors that with his "force daily diminished by sickness," he could not resist the siege. He claimed that half his men were too sick to stand duty.
Why didn't the French and Americans fall ill, too? Some did, but far fewer and too late to matter. With malaria it takes about a month between infectious bite and the onset of symptoms. The British had been absorbing the parasite since June, but the Franco-Americans arrived in the Tidewater only in September. So malaria had two extra months to work its mischief in British ranks.
Moreover, most of the Americans had grown up with malaria. Those who had not suffered heavily in the week before the surrender. Malaria felled French soldiers, too, most of whom were just as vulnerable as the redcoats, but mainly after Oct. 19.
Once committed to Yorktown, Cornwallis faced a biological warfare campaign he could not counter. Mosquitoes helped the Americans snatch victory from the jaws of stalemate and win the Revolutionary War, without which there would be no United States of America. Remember that when they bite you next Fourth of July.


Students from Highlander Charter School in Providence, Rhode Island, wait to tour the Rotunda on Capitol Hill. The students sit in front of "Surrender of Lord Cornwallis," depicting the surrender of the British army at Yorktown, Virginia, in 1781, which ended the last major campaign of the Revolutionary War. (Melina Mara - Melina Mara/The Washington Post)

McNeill is a Georgetown University professor of environmental history and author of many books, including "Mosquito Empires: Ecology and War in the Greater Caribbean, 1620-1914."

http://www.washingtonpost.com/wp-dyn/content/article/2010/10/18/AR2010101803877.html

MALARIA: World Mosquito Day 2010

INTERESTING VIDEO WITH HISTORICAL SHOTS

113 years ago today, British doctor Ronald Ross first made the link that female mosquitoes transmit malaria between humans. It was 20th August 1897 and on making this discovery Dr. Ross declared that this day be known as World Mosquito Day.
Dr. Ross’s discovery laid the foundations for scientists across the world to better understand the deadly role of mosquitoes which currently infect 250 million people with malaria every year, causing 850,000 deaths, mostly in young children in Africa.
Malaria No More UK has created a three minute film to highlight the history and significance of the day. The film features little seen footage of Dr Ross as well as interviews with some of today’s key players in the fight to make malaria no more including Ray Chambers, co-founder of Malaria No More and the UN Secretary-General’s Special Envoy for Malaria, Stephen O’ Brien, International Development Minister, and Geoff Targett, Emeritus Professor of Immunology of Parasitic Diseases at London School of Hygiene and Tropical Medicine.
Their messages bring hope and perspective – making malaria no more in Africa a genuine possibility.
According to Ray Chambers, the 2010 goal to provide mosquito nets to all at risk in Africa is in sight. Ray says: “We are at the closest point in history to reaching the first malaria goal to ensure all those in Africa who need a life-saving net have access to one. We believe this will be a reality for all 700 million people who need a net and that they will sleep safely at night just months from now”.
http://malarianomore.org.uk/world-mosquito-day-2010

MALARIA: tracking its origins

Malaria is an ancient and persistent disease. It wasn’t eradicated in the United States until the 1950s, and it is still devastating in developing countries around the world. The latest estimate from the World Health Organization is that in 2008 the disease killed more than a million people and afflicted 247 million others.
Scientists have long speculated about just how ancient the disease is, and when the human malaria parasite originated, with wildly varying estimates from 10,000 years to several million years ago.
Now, using statistical modeling and DNA analysis, a group of researchers report in the journal Science that ancestors of humans first acquired the malaria parasite known as P. falciparum 2.5 million years ago. But, the researchers wrote, the parasite probably did not cause disease in humans until much more recently, perhaps 10,000 years ago at the beginning of agriculture.
The researchers linked the rate of evolution in the parasites to the rate of evolution in bird hosts in the West Indies. They were able to estimate the rate at which malaria parasites would have had to diversify in order to spread to other hosts, like mammals.
As for the public health benefits of the malaria dating, there may not be too many. “Knowing how old the human malaria is isn’t going to do much in the way of curing it,” said Robert E. Ricklefs, a biologist at the University of Missouri at St. Louis and the study’s lead author.
http://www.nytimes.com/2010/07/20/science/20obmalaria.html?_r=1

MALARIA: King Tut

King Tutankhamun died from sickle-cell disease, not malaria, say experts. A team from Hamburg's Bernhard Noct Institute for Tropical Medicine (BNI) claim the disease is a far likelier cause of death than the combination of bone disorders and malaria put forward by Egyptian experts earlier this year.
The BNI team argues that theories offered by Egyptian experts, led by antiquities tsar Zahi Hawass, are based on data that can be interpreted otherwise. They say further analysis of the data will confirm or deny their work. Hawass' claim, published in the Journal of the American Medical Association this February, and followed by a swarm of accompanying television shows, claimed King Tut suffered from Kohler's disease, a bone disorder prohibiting blood flow, before succumbing to malaria.
Multiple bone disorders, including one in Tutankhamun's left foot, led to the Kohler's diagnosis, while segments of a malarial parasite were found via DNA testing. Yet the BNI team claims the latter results are incorrect. “Malaria in combination with Köhler's disease causing Tutankhamun's early death seems unlikely to us,” say Prof Christian Meyer and Dr Christian Timmann.
Instead the BNI team feels sickle-cell disease (SCD), a genetic blood disorder, is a more likely reason for the Pharaoh's death aged just 19. The disease occurs in 9 to 22 per cent of people living in the Egyptian oases, and gives a better chance of surviving malaria; the infestation halted by sickled cells.
They say the disease occurs frequently in malarial regions like the River Nile, and that it would account for the bone defects found on his body.
“The genetic predisposition for (SCD) can be found in regions where malaria frequently occurs, including ancient and modern Egypt.” says Meyer. “The disease can only manifest itself when a sickle cell trait is inherited from both parents: it is a so-called 'recessive inheritance'.” A family tree for the Pharaoh suggested by Hawass himself appears to back the BNI team's case.
The relatively old age of Tutankhamun's parents and relatives – up to 50 years – means they could very well have carried sickle-cell traits, and could therefore have been highly resistant to malaria. The high likelihood that King Tut's parents were siblings means he could have inherited the sickle cell trait from both and suffered from SCD.
“Sickle-cell disease is an important differential diagnosis: one that existing DNA material can probably confirm or rule out,” conclude Timmann and Meyer. They suggest that further testing of ancient Egyptian royal mummies should bear their conclusions in mind.
King Tut's young demise has long been a source of speculation. As well as malaria, recent decades have seen scholars argue that he was murdered, and that he died from infection caused by a broken leg.
http://www.independent.co.uk/news/science/archaeology/news/king-tut-died-from-sicklecell-disease-not-malaria-2010531.html

MALARIA: advice to travellers

To watch children slip into the potentially fatal clutches of malaria is terrifying. It's the speed of the descent from good health to serious illness that is so frightening: at dawn they are fine, by dusk they could be in a coma, from which they might never wake. I know this because several years ago I was there – panic-stricken – watching my then eight-year old son, his mind drowning in delirium and his young body teetering on the brink of collapse.
He begged me to 'Just let me close my eyes for a bit, mum', and, desperate, I pleaded with him to stay awake. His decline took less than six hours. In the end he was fine – it meant an emergency airlift, an admission to hospital where he was administered artemisinin (a drug derived from the plant Artemesia annua) intravenously, and four long recuperative weeks out of school, but he did make a full recovery. We were lucky, luckier than the parents of the estimated 5,000 children that die from malaria every day.
Malaria is the world's biggest killer. It affects almost 500 million people a year and takes the lives of nearly 3 million – mostly in Africa, where a child is estimated to die from the disease every 30 seconds, at an estimated cost to the economy of more than £6bn a year.
Despite its much publicised Roll Back Malaria Partnership, the World Health Organisation has had limited success in 20 years. The only real impact the programme has had on the disease is through the introduction of insecticide-treated nets (ITNs), which are an effective prophylactic, particularly for children, when used correctly (but which remain heavily taxed in much of Africa).
Most of the world's millions of malaria sufferers are still not benefiting from life-saving drugs nearly five years after the WHO urged their widespread use. Since 2001, the UN health agency has recommended countries switch to artemisinin-based combination drugs (or ACTs) to treat malaria, which has become resistant to conventional medicines, like chloroquine.
The majority of sufferers understand very little about the disease or how it is transmitted (by the female mosquito, which must be pregnant, and which only bites between dusk and dawn).
Ronald Ross, a British doctor born in India, discovered it was the mosquito that transmitted malaria. Until then the popular theory was that foul-smelling gases emitted from swampy soils caused the disease – the word 'malaria' comes from the Italian, 'bad air'. The mortality rate at the time – over a million deaths a year – was reduced to less than 10,000 during the 1950s as a direct result of education and the eradication schemes initiated by Ross. Since the 60s, though, the disease has been on the increase – in 1960 only 10% of the world's population was at risk; that figure now stands at over 40%.
Today, as a result of poor vector control, global warming and intercontinental travel, malaria infects one in 10 of the world's population. It is present in over 100 countries (including eastern Europe, Russia and Turkey), visited by more than 125 million tourists every year, up to 30,000 of whom fall ill when they get home. Last year 1,754 Britons contracted malaria abroad – 1,300 of them the deadliest strain, Plasmodium falciparum (or cerebral malaria). Eleven of them died.
Poverty and poor education compound the problem of malaria in third-world countries, elevating mortality rates. Astonishingly, ignorance of the disease – despite the press coverage it receives and the access to world-class medicine – is a factor in first-world infection, too. Most British travellers who were infected with malaria last year admitted to failing to take correctly – or at all – oral malarial prophylaxis when visiting areas where the disease is endemic.
An investigation conducted earlier this year in the UK found that travellers who sought advice from alternative health centres (complaining that drugs prescribed by their GPs made them feel nauseous) were being offered 'dangerous' advice on malaria prevention and given unproven homoeopathic remedies. Conventional drugs prescribed by GPs are a combination of chloroquine and proguanil, mefloquine (Lariam), doxycycline and Malarone.
As a resident in Africa, I questioned my own doctor about the efficacy and side effects of these drugs. He dismissed chloroquine and proguanil as almost useless, since the parasite has been shown – in this region anyway – to have developed significant resistance to the combination. Lariam, he said, can cause serious neurological disturbances in as many as one in 10 people. Doxycycline increases photosensitivity, which means patients must be prepared to stay out of the sun. It can also interfere with the potency of oral contraception. Malarone, the most recent anti-malarial to be registered, is considered both effective and relatively easily tolerated, but expensive.
Without exception, all short-term visitors to a malarious area should seek advice from the experts (which include the London School of Hygiene and Tropical Medicine, the WHO and the Health Protection Agency) on malarial prophylaxis beforehand. The situation, however, is more complicated for expatriates living in endemic areas, partly because of the risk associated with long-term use of chemoprophylaxis and partly because there is limited data available on the sustained use of some drugs.
The Health Protection Agency suggests that 'the risk of serious side effects associated with long-term prophylactic use of chloroquine and proguanil is low. However, anyone who has taken chloroquine regularly for over five years and requires further prophylaxis should be screened twice-yearly for early retinal changes'. Even before these changes become apparent, there could be other intolerable side effects: my husband, for example, is unable to take proguanil (Paludrine) as it gives him appallingly bad mouth ulcers, which render him unable to eat.
Research suggests there is no increased risk of serious side effects with long-term use of mefloquine (Larium), assuming a person can tolerate it in the short term. Experience of doxycycline in long-term use is limited, though the available data is reassuring (however, like mefloquine, it must be avoided during pregnancy). In many parts of the world, oral prophylaxis is not a guaranteed form of protection; Plasmodium falciparum is increasingly resistant to various antimalarial drugs (indeed my son was on a chloraquine/proguanil combination when he contracted this particularly virulent strain of the disease). As the WHO warns, no antimalarial prophylactic regimen gives complete protection.
Those travelling to malarious areas for extended periods of time (over six months) – or living there (particularly in the case of women, who may become pregnant, and young children) – need to balance the risk of infection against the benefits and side effects of oral prophylaxis; sometimes taking a pill daily gives a false sense of security and might result in laziness when it comes to other prophylactic measures – sleeping under nets, for example, spraying rooms or burning mosquito coils at night.
The basics
Expatriates, 30% of whom develop malaria within two years, need to be vigilant about not being bitten, rather than relying on chemoprophylaxis alone, as chemoprophylaxis has been shown to be insufficient protection. Prevailing guidelines, as laid out by the WHO and HPA, promote four (ABCD) principles of malaria protection:
• Be aware of the risk, the incubation period (from seven days up to several months) and the main symptoms: flu-like to begin with, chills, headache . Sometimes a cough develops.
• Avoid being bitten by mosquitoes, especially between dusk and dawn – apply mosquito repellent to the skin, wear long sleeves, trousers, socks and shoes, sleep under a light in a room where a coil is being burned. Sleeping under a fan or in an air-conditioned room can also help, as can fixing mosquito mesh to windows.
• Take antimalarial drugs (chemoprophylaxis), as advised by a doctor, to prevent infection from developing into clinical disease.
• Immediately seek diagnosis and treatment if a fever develops one week or more after entering an area where there is a risk of malaria, and up to three months (and even longer) after departure from a risk area. Early diagnosis and treatment can be life-saving; Plasmodium falciparum can be fatal within 24 hours. A blood sample should be examined for malaria parasites. If no parasites are found in the first slide yet clinical suspicion of malaria remains, a series of blood samples should be taken at six- to 12-hour intervals and examined vigilantly. Sometimes taking a chemoprophylaxis can mask results, so this should always be mentioned to an examining doctor. In the end, as my doctor here observes, the only sure-fire way to avoid infection in a malarial area is to avoid being bitten.
http://www.guardian.co.uk/money/2008/mar/19/expat-finance-malaria-prevention

MALARIA: Historical aspects

Kicking off proceedings was LSHTM’s Professor Brian Greenwood, a legend in malaria research, who painted a picture of how malaria treatment used to be – and how much it has changed.
Forty years ago almost every African child had malaria, with an estimated prevalence of 95 per cent (though Greenwood reckoned it was nearer to 100 per cent in reality). Yet, at the time, confidence in malaria treatments was high. The front-line anti-malaria drugs such as chloroquine were effective and anti-malarials for prophylaxis were widely sold. “We didn’t have seminars about malaria,” said Greenwood, “People didn’t feel there needed to be [any]”.
But that was before the spectre of anti-malaria drug resistance emerged. Following the first report in 1968, resistance spread rapidly through the continent, rendering many of the front-line treatments ineffective and forcing a major rethink of treatment strategies.
A serious barrier was changing doctors’ behaviour. Despite the fact that resistance was widely acknowledged, chloroquine continued to be (mis-)used. Why?
“Everyone liked chloroquine,” said Greenwood, “Doctors had confidence in it from years of effective use, and doctors are very conservative by nature. Getting them to change their minds was a hard task.”
Moreover, chloroquine had benefits beyond malaria. It is an effective anti-inflammatory, one of the reasons the drug was always prescribed, even if the patient didn’t have malaria. Said Greenwood, “It was thought to be fine to do so as they were always likely to benefit”.
Furthermore, there was a widespread (erroneous) belief that having a few parasites circulating in the body ‘stimulated the immune system’. It was common practice in many places to give patients just one day of a three-day course of chloroquine.
We now know that many of these practices are detrimental to health and a boon to increasing the resistance of the parasite to the drug. The patient could develop anaemia or the parasite could recover and cause another bout of malaria.
By the 1990s the malaria community had learnt that treatment should eliminate all parasites. This was in no small part due to pioneering research by scientists such as Professor Nick White from the Wellcome Trust’s Major Overseas Programme in Thailand (in South-east Asia the idea of leaving parasites around for immunity was never fully accepted). Also, from treating tuberculosis, researchers and healthcare workers soon realised that the use of mono-therapies – and overuse of them at that – was helping to increase drug resistance.
We now know the importance of diagnosing and only treating those who really have malaria, yet the relative slowness with which the community recognised these dangers was disastrous. Even today the idea of leaving a few parasites in the body has not completely been dispelled. As Greenwood said, it’s taken a long time to learn those messages and we are mostly there now, but the message must continue to be broadcast.
http://wellcometrust.wordpress.com/2010/04/26/counting-malaria-out-malaria-treatment-as-it-used-to-be/