Malaria, DDT and UN Long Awakening


Diamond Member
Nov 22, 2003

WHO Calls for More DDT Use Vs. Malaria
World Health Organization Urges Developing Countries to Use DDT More-Outdoors-In Malaria Fight
The Associated Press

WASHINGTON - The World Health Organization on Friday called on more developing countries, particularly in Africa, to begin spraying the controversial pesticide DDT to fight malaria.

The difference: DDT, longed banned in the United States because of environmental damage, is no longer sprayed outdoors. Instead it's used to coat the inside walls of mud huts or other dwellings and kill mosquitoes waiting to bite families as they sleep.

A small number of malaria-plagued countries already use DDT, backed by a 2001 United Nations treaty that set out strict rules to prevent environmental contamination. But the influential WHO's long-awaited announcement makes clear that it will push indoor spraying with a number of insecticides and that DDT will be a top choice because when used properly it's safe, effective and cheap.

"We must take a position based on the science and the data," said Dr. Arata Kochi, the WHO's malaria chief. "One of the best tools we have against malaria is indoor residual house spraying. Of the dozen insecticides WHO has approved as safe for house spraying, the most effective is DDT."

"It's a big change," said biologist Amir Attaran of Canada's University of Ottawa, who has long pushed for the guidelines and described a recent draft. "There has been a lot of resistance to using insecticides to control malaria, and one insecticide especially. ... That will have to be re-evaluated by a lot of people."

The U.S. government already has decided to pay for DDT and other indoor insecticide use as part of President Bush's $1.2 billion, five-year initiative to control malaria in Africa.

Kochi has positioned indoor spraying as an important but neglected third weapon along with insecticide-treated bed nets and new medications in the war on malaria, which infects half a billion people each year and kills more than 1 million, most of them children.

While some well-known environmental groups have signed on to WHO's decision, it has generated some concern from groups like the Pesticide Action Network, which says there are questions about its effects on developing children.

But proponents argue that until better strategies are developed, carefully controlled DDT use is warranted because in recent years, nothing else has succeeded in lowering deaths from malaria.

"Indoor spraying is like providing a huge mosquito net over an entire household for around-the-clock protection," said Sen. Tom Coburn, R-Okla., a physician who has urged stronger international anti-malaria programs.

DDT is easily history's most notorious insecticide. While it isn't classified a human health hazard, it was banned in the U.S. in 1972 after decades of widespread agricultural spraying led to environmental damage around the globe.

DDT never disappeared in developing countries, although political pressure and lack of funding meant few continued to use it. Then a 2001 United Nations treaty that aims to wipe out a dozen of the world's most dangerous chemicals carved out one exception for DDT: indoor anti-malaria spraying, under strict conditions to prevent environmental contamination.

Why? When small amounts are sprayed on interior walls, DDT forms a residue that both repels mosquitoes discouraging them from flying into the house and kills those that rest on the walls, explained Clive Shiff, a professor at Johns Hopkins University's Malaria Research Institute. It has to be applied only about once a year.

Bednets soaked in different insecticides already are used to protect sleeping families. But if the nets are torn or aren't used every night, a mosquito can infect someone. Plus, mosquitoes can develop resistance to those nets' chemicals, Shiff added, pointing to a 2002 malaria outbreak in part of South Africa using bednets. DDT in those houses quelled the outbreak.

"It would be naive to say DDT is a magic bullet for malaria. It isn't," stressed Attaran. It won't work in some places where mosquitoes already are resistant to a range of insecticides, he noted. He suspects DDT will be of most use in eastern Africa, where that problem hasn't yet emerged.

Attaran called for research "to make sure we're using insecticides and DDT not in a willy-nilly way but in an optimal way in the right places."...

November 29, 2000

Greens vs. the World's Poor
Limited use of DDT could save millions from malaria. So why are environmentalists and the U.N. hellbent on ending its production?

By Ronald Bailey, Reason Science Correspondent

Imagine that an international governing body got together with a cadre of special interests to deny millions of poor people access to a cheap substance capable of saving hundreds of thousands of lives annually. You'd think such an effort would be considered highly immoral, right? Probably even cause street demonstrations, boycotts, and other signs of public outrage.

Well, just such a campaign was launched three years ago by the United Nations Environmental Program, acting in conjunction with several major environmentalist organizations. There have been no demonstrations, no boycotts, and sadly, few signs of outrage.

That's because the substance is the much-vilified pesticide DDT, which remains the cheapest and most efficient means of reducing malaria. Malaria sickens 300 to 500 million poor people annually, killing as many 2.7 million. In sub-Saharan Africa, one in 20 children dies of malaria. That toll could go higher if a new United Nations Treaty on Persistent Organic Pollutants (POPs) is concluded next week in Johannesburg, South Africa. The POPs Treaty, which is being negotiated by more than 120 governments and is backed by more than 260 environmentalist groups, aims to eliminate totally the production and use of 12 organic pesticides, industrial chemicals, and byproducts, including DDT. Many of these substances are alleged to have unacceptable environmental and health consequences.

DDT has, of course, been a major target for the environmentalist movement ever since Rachel Carson hexed it in her influential 1962 book, Silent Spring. Widely used as an agricultural pesticide, Carson accurately indicted DDT for harming various forms of wildlife. Less accurately, she and others in her wake fingered residual DDT as causing problems in human beings, including increased rates of cancer. In 1972, the U.S. Environmental Protection Agency, then only two years old, banned it, a policy adopted by many other countries. Worldwide use of the pesticide plummeted. DDT remains a powerful symbol of environmental sin and environmentalists have literally been pursuing it to the ends of the Earth in their efforts to banish it forever. Elimination under the POPs Treaty was to be their final triumph over this accursed chemical.

However, it turns out that spraying small quantities of DDT on the interior walls and eaves of living spaces is one of the most effective ways to control malaria-carrying mosquitoes. In fact, during the 1950s and 1960s, DDT use nearly eradicated malaria in many countries. For example, malaria in Sri Lanka dropped from 2.8 million cases in 1948 to 17 in 1963. In India, the case load dropped from 100 million in 1935 to under 300,000 in 1969. Bangladesh was declared a malaria-free zone. DDT was also an important weapon against malaria in parts of the United States and Italy. The World Health Organization estimates that DDT may have saved as many as 50 million lives since it was introduced in 1945. A grateful world cheered when the man who discovered DDT’s properties as an insecticide was awarded the Nobel Prize in 1948.

But that was then. As part of the U.N.’s POPs negotiations, the World Wildlife Fund (WWF) and other environmentalist groups have argued that DDT should be totally banned by 2007. Alarmed, the world’s malaria control organizations have been fighting back.

"We said, ‘It’s a bad idea and it’s going to kill people,’" explains Amir Attaran, who works on this issue at Harvard University’s Center for International Development. "The environmentalists sought to promote an environmental goal at a calculated risk to human life." The Malaria Foundation International circulated an open letter that has been signed by more than 600 of the world’s leading malariologists and other scientists, arguing that "setting a firm deadline to ban DDT places an unethical burden on the world’s poorest countries." According to former Surgeon General of the U.S. Navy, Harold Koenig, "DDT remains probably the most effective, affordable tool with which to fight malaria in the developing world."

In the wake of such criticism, environmentalist groups have backed away a bit from advocating a firm deadline for eliminating DDT. Richard Liroff, head of the WWF’s Alternatives of DDT project, now says that "the only purpose of the deadline was to motivate technical and financial resources to help poor countries come up with alternative malaria control strategies." The August 2000 WWF statement on Eliminating DDT and Protecting Public Health acknowledges that "negotiators need to ensure that human health is not compromised as reliance on DDT is reduced." Liroff also points out that the WWF and other groups have accepted a proposal by South Africa that would exempt DDT for disease-control uses (as opposed to agricultural ones), although the parties to the POPs Treaty would periodically "evaluate the continued need for this exemption." "Some people are trying to make this controversy fit the caricature of tree huggers not caring about people, but it’s not true," Liroff insists.

Chalk one up for the good guys? Not so fast.

First, Harvard’s Attaran worries that the procedural barriers and controls put on DDT by the POPs Treaty may raise its cost so much that many poor countries will not be able to afford to continue using it. Second, the WWF Core Issues Statement on the Johannesburg conference still asserts that "negotiators need to remain firm and committed to making elimination the central objective of the POPs Treaty." That includes DDT. Similarly Greenpeace’s briefing paper on the Johannesburg meeting insists that the POPs Treaty must adopt "measures to put an end to the production of and use of all existing POPs." Again, that includes DDT.

So the total elimination of DDT remains the real goal. Attaran points out that Greenpeace is currently trying to shut down one of the world’s two remaining manufacturers of DDT in India. "Thus they may accomplish through the back door what they couldn’t accomplish through the front door," says Attaran.

Why this relentless pursuit of DDT down to the last molecule? Vice-President Albert Gore suggests one answer in his introduction to the 1994 reissue of Silent Spring, a book often cited as the founding text of contemporary environmentalism. Before Carson's book, he writes, "There was virtually no public dialogue about the growing, invisible dangers of DDT and other pesticides and chemicals." The fears that have come down the decades from Rachel Carson are summarized in the WWF Core Issues Statement, which claims that "even small quantities of …POPs can wreak havoc in human and animal tissue, causing nervous system damage, disease of the immune system, reproductive and developmental disorders, and cancers." Eliminating POPs generally, and DDT specifically, are at the very heart of the modern environmentalist movement.

Doing so may be a noble cause to greens, but the cost of success will be measured in human lives. Setting aside health concerns about other POPs, and accepting that using DDT in agriculture harmed wildlife, it simply isn't true that using DDT to control malaria is a health risk.

"The scientific literature does not contain even one peer-reviewed, independently replicated study linking DDT exposures to any adverse health outcome" in humans, says Amir Attaran. "No study in the scientific literature has shown DDT to be the cause of any human health problem," concludes Richard Tren and Roger Bate in When Politics Kill: Malaria and the DDT Story, a new study from the Competitive Enterprise Institute.

Such facts have failed to undermine environmentalist dogma. "Because Carson’s work led to the ban on DDT," Al Gore concluded in his commemorative introduction to Silent Spring, "It may be that the human species…or at least countless human lives, will be saved because of the words she wrote."

Sadly, it's more likely that, because a blinkered orthodoxy cannot accept the heretical notion that DDT has some beneficial purposes, countless human lives will be lost.

Ronald Bailey ( is Reason Magazine's science correspondent.
DR-malaria in SE Asia...
Scientists Race to Contain Malaria: New Discoveries, More Resistance
May 17, 2013 - Two new medical discoveries are raising hopes of containing malaria - the mosquito-borne parasitic disease that each year infects more than 200 million people and claims an estimated 660 thousand lives. Meantime, the World Health Organization is warning about dire consequences if a drug-resistant form of malaria spreads beyond southeast Asia.
Artemisinin has helped cut global malaria deaths by more than 25 percent over the past decade. But now, in parts of Southeast Asia, this drug no longer works. And the World Health Organization's Dr. Shin Young-Soo warns of serious setbacks if drug resistance continues to spread. "The truth is, that malaria will beat us all unless we do more than what we are doing now, and we do it better," he said. Controlling malaria involves a range of strategies: using insecticidal bed nets to prevent mosquito bites, spraying insecticides, preventive treatment for children and pregnant women, and controlling or changing mosquitoes, or the malaria parasites they carry.

The World Health Organization says that in the last 10 years, 20 countries have brought the disease under control. At a U.S. congressional hearing, Dr. Mark Dybul executive director of the Global Fund to Fight AIDS, Tuberculosis and Malaria, said the world is on course to end malaria. "We've had so much success over the last 10 years that you've heard about, that high-transmission areas are becoming much more confined," said Dybul. Dybul said global efforts have led to better treatment and more effective control of the mosquito that carries the parasite.

Dr. Anthony Fauci, at the US National Institutes of Health, points to promising research that involves introducing a strain of bacteria into the mosquito. "It's a bacteria that infects the mosquito, and what it does is it interferes with the developmental process that the malaria parasite goes through in the mosquito in its lifecycle," said Fauci. And once the bacterium is in the mosquito, it's passed down to succeeding generations. The hope is, these malaria-proof mosquitoes eventually will replace those that can carry the parasite. "Which means, if you can get this out there among populations of mosquitoes in different regions of the world in different countries, it could have a profound effect on the control of malaria," said Fauci.

The true test, of course, will come when mosquitos infected with the bacterium are released into the wild. Dr. Guowu Bian is the Michigan State University scientist who led this research. He spoke to VOA via Skype. "I hope in a few years, maybe three or four years, our mosquito can go to the field," he said. Another promising line of research involves manipulating the mosquito's genes. Right now, the anopheles mosquito has no defense against the malaria parasite. If scientists can change its genetic makeup, the mosquito's immune system could repel the organism. Meanwhile, the clock is ticking as the malaria parasite becomes immune to the world's front-line drug against the disease.

New species-specific insecticide against malaria parasite...
Scientists Developing New Weapon Against Malaria
May 28, 2013 - Scientists are making progress in developing a new species-specific insecticide that would be lethal only to insects that carry malaria.
According to scientists at Virginia Tech and the University of Florida the insecticide would be far less toxic to beneficial insects such as bees. They say the insecticide is formulated to interfere with an enzyme found in the nervous system of mosquitoes and other organisms called acetylcholinesterase. If the effectiveness of the enzyme is disrupted, it causes an organism to convulse and die. “A simple analogy would be that we’re trying to make a key that fits perfectly into a lock,” said entomologist Jeff Bloomquist, a professor at the University of Florida's Emerging Pathogens Institute and its Institute of Food and Agricultural Sciences. “We want to shut down the enzyme, but only in target species.”

Scientists are trying to perfect the mosquito-specific compounds and manufacture them on a large scale so that they can be applied to netting where mosquitoes might land. They say it will take at least four to five years before a compound is ready to be submitted for federal approval. The team recently published a study in the journal Pesticide Biochemistry and Physiology comparing eight experimental compounds with commercially available insecticides that target the enzyme.


Vehicles move past Pakistani day laborers sleeping under a mosquito net. A new insecticide could be sprayed on nets to kill mosquitoes.

Though they were less toxic to mosquitoes than commercial products, the experimental compounds were far more selective, indicating researchers are on the right track, Bloomquist said. “The compounds we’re using are not very toxic to honeybees, fish and mammals, but we need to refine them further, make them more toxic to mosquitoes and safer for non-target organisms,” he said.

Malaria is caused by microscopic organisms called protists, which are present in the saliva of infected female mosquitoes and transmitted when the mosquitoes bite. Initial symptoms of the disease can include fever, chills, convulsions, headaches and nausea. In severe cases, malaria can cause kidney failure, coma and death. Worldwide, malaria infected about 219 million people in 2010 and killed about 660,000, according to the Centers for Disease Control and Prevention. About 90 percent of those infected lived in Africa.

Mom's-to-be in Sub-Saharan Africa need better malaria protection...
Study: Pregnant Women Not Gaining Access to Malaria Prevention
July 23, 2013 - Malaria infections, primarily in sub-Saharan Africa, are responsible for the deaths of some 200,000 newborns and 10,000 new mothers each year. The parasitic illness can also cause miscarriage and premature birth, increasing the risk of death. There are low cost, lifesaving interventions to prevent infection, yet, according to a new study, there are significant barriers to implementing them.
For the past 20 years, the World Health Organization (WHO) has recommended that pregnant women in areas with high rates of malaria receive insecticide-treated bed nets and periodic doses of a cheap drug to prevent the disease. Yet, despite relatively high attendance at clinics for expectant mothers and their newborns throughout sub-Saharan Africa, statistics show that just a little over 21 percent of women are receiving intermittent preventive treatment in pregnancy, or IPT, and fewer than 40 percent of them are being given protective bed nets.

Jenny Hill of the Liverpool School of Tropical Medicine is program manager for a research partnership called the Malaria and Pregnancy Consortium. Hill says an analysis of 99 studies found a number of barriers to malaria prevention, including unclear policy and guidance from government ministers and health care officials and, at the clinical level, lack of clean water, drug shortages and confusion about procedures for administering IPT. “They were unclear on when to give it in terms of gestational age of pregnancy and whether it could be given to women on an empty stomach, whether it should be given under observation in clinics, and so on and so forth," she said. "So quite a few of those barriers were around lack of clear policy and guidance.”


A child rests under a mosquito net in Marka's main hospital in Somalia

The WHO recommends that expectant women receive IPT during regular visits to pre-natal clinic, usually around four times in the course of a pregnancy. Free intermittent preventive treatment of pregnancy is the policy in 37 countries across the region, according to Hill. Yet, investigators found pre-natal clinics, known as ANCs, posed economic obstacles which discouraged women from coming back. “When they arrive at the clinic for a first ANC visit they have to register, and that requires a registration," she said. "And there are also fees around getting lab tests and around some drugs.”

Hill says countries can reduce the number of deaths and pre-term births due to malaria by ensuring the WHO policy on IPT is fully implemented, earmarking more money for drugs so there’s no shortage, and publicizing the importance of malaria prevention among women at highest risk for the parasitic illness. “They are very powerful interventions that could go a long way to reducing the burden of malaria and improving the outcomes, both in pregnant women and their infants,” she said. An analysis of maternal and infant malaria prevention measures is published in the journal PLoS Medicine.

Study: Pregnant Women Not Gaining Access to Malaria Prevention
Government warns against use of anti-malaria drug...
Federal officials issue strong new warning about anti-malaria drug
August 2, 2013 — Federal drug officials have issued a strong new warning about a controversial anti-malaria medication once routinely given to U.S. troops, some of whom say it damaged them permanently.
The Food and Drug Administration ordered manufacturers of mefloquine hydrochloride to give the medicine a black box label, the agency's strongest warning, reserved for drugs with significant risks of serious side effects. The FDA said that some neurological and psychiatric side effects can last for months or years after a patient stops taking the drug. The medication was approved by the FDA in 1989 under the brand name Larium and quickly became a leading drug for preventing and treating malaria — among travelers and the military. While other drugs must be taken daily, one tablet a week of mefloquine offers protection against the sometimes-deadly mosquito-borne parasite, including against strains that are resistant to other medications.

But the drug has long carried warnings tying it to dizziness, seizures, insomnia, anxiety, depression and strange dreams. One clinical trial found that 29% of travelers who took mefloquine experienced at least one of those side effects. There is also evidence suggesting a link to violent behavior, including suicide. Amid growing concerns, the drug fell out of favor over the last decade. Roche, its original manufacturer, stopped selling Larium in the U.S. in 2008. The generic versions still on the market accounted for 226,000 of the 5.4 million U.S. prescriptions for anti-malaria drugs last year, according to IMS Health, which tracks drug trends. The Pentagon, which used the drug widely in Somalia and during the early years of the wars in Iraq and Afghanistan, offered little explanation when it began scaling back its reliance on mefloquine and eventually recommended that the drug be used only as a third choice. Military officials continued to dismiss the claims of veterans who insisted that the side effects could be long-lasting.

The new FDA warning provided those veterans a sense of validation. "I almost fell out of my chair when [the news] was forwarded to me," said Greg Alderete, a retired Army lieutenant colonel who blames his chronic balance and memory problems on the drug, which he took while serving in Somalia in 1993. Alderete said that in 2008 he started to suspect mefloquine after connecting with other veterans of Somalia who were experiencing similar symptoms. He eventually helped launch a Facebook group, Veterans Against Larium, which now has more than 1,100 members. He said most served in Somalia, but the group has also attracted veterans from other wars.

Alderete acknowledged that his depression, anger and anxiety could be the result of post-traumatic stress disorder, with which he was diagnosed. But his chronic dizziness and nausea and an inability to remember words are less easily explained. "There was a big gray zone," he said. "I'm not sure where mefloquine begins and PTSD ends." Doctors from the U.S. Department of Veterans Affairs have insisted that his problems are not related to the drug, he said. The FDA strengthened its warning this week based on a new review of medical literature and reports of patients suffering from dizziness, loss of balance, tinnitus and vertigo, according to a statement from the agency. The symptoms often started after the first dose or two but continued for months or years. In some cases, the damage was deemed permanent. Usually, the neurological symptoms were accompanied by psychiatric ones, including anxiety, confusion, paranoia and depression, which were also long-lasting.

Thanks for the thread

The Greenies demand things when they don't have the faintest idea of what the global consequences may be. Probably as many die from malaria as those in wars and terrorist attacks - the majority being the old and young.
Usin' malaria to kill syphilis???...
Austrian children injected with malaria in 1950s
Sun, May 04, 2014 - An Austrian commission investigating claims that doctors deliberately infected patients with malaria to treat other patients with syphilis said hundreds of people, including orphans in a psychiatric hospital, might have been infected.
The commission started work last year following accusations by former patients who were orphaned children on a psychiatric and neurological ward run by the city of Vienna in the middle of the 20th century. Lawyer Johannes Oehlboeck, who represents some of them, told reporters on Friday that several believe they were used as “carriers” to keep the malaria parasite alive until it could be injected into syphilis patients, in a medical therapy once thought to be effective.

Malaria is a potentially fatal disease that is usually spread by infected mosquitoes. Most deaths occur in children under 5. Commission head Gernot Heiss said on Friday last week that ongoing investigations of the period from 1951 to 1969 show that 230 people, including some children on the ward, were injected with the parasite, all between 1955 and 1960.

The injections normally caused two weeks of fever as high as 42°C, as well as sudden fever attacks continuing up to two decades. The fever caused by malaria was meant to kill the syphilis infection. The commission has so far examined 5,140 medical histories and Heiss said it expects to end its work next year with a ruling on whether the practices reflected modern medical standards of the time. Heiss said that “malaria therapy” was “recognized and practiced worldwide” until the early 1960s. He did not comment on the suspicions by the clients of Oehlboeck, the Vienna lawyer.

In 1927, Austrian psychiatrist Julius Wagner-Jauregg received the Nobel Prize in Medicine for using malaria to treat people with a severe form of syphilis that infects the brain and can cause delusions, psychosis and paralysis. Doctors in Britain and the US also used the treatment, sometimes using mosquitoes to infect their patients. The later introduction of penicillin to treat infections and other therapies ultimately made malaria therapy obsolete.

Austrian children injected with malaria in 1950s - Taipei Times
Granny says, "Dat's right - wash with Faso Soap an' wash dem skeeters away...

Mosquito-repellent Soap Invention Seeks to Fight Malaria in Africa
May 12, 2016 — Two former students from Burkina Faso have designed a mosquito-repellent soap, which they hope could be a simple and affordable solution in the fight to end malaria, but more funds are needed to test the idea, according to the startup behind it.
Moctar Dembélé and Gérard Niyondiko, the brains behind Faso Soap, were awarded a $25,000 prize for their invention in 2013 when they became the first African winners of the Global Social Venture Competition at the University of California Berkeley. Yet Faso Soap must be tested to ensure it is safe for human use and effective at preventing malaria before it can be mass produced by soap manufacturers in Africa, said Franck Langevin, campaigns director for the Ouagadougou-based startup. The soap, created from natural oils and plants, could prove successful in preventing malaria as it would be cheap and rely on existing habits of African households, Langevin said. "People in Africa are very reluctant to change their habits, but soap is present in most homes, and is used for bathing, cleaning the house and washing clothes," he said.

The soap is designed to repel mosquitoes up to six hours after being applied, and once soapy water is thrown away on the street, hinder the insects from breeding in stagnant water. "It is a simple and affordable weapon in the fight against malaria," Langevin told the Thomson Reuters Foundation. Last month, Faso Soap launched a crowd funding appeal for $113,000 to finalize the development of the soap with the aim of distributing it in six African countries hardest-hit by malaria by 2018, working with soap manufacturers and aid agencies.


A photo provided by the Centers for Disease Control and Prevention shows a female Aedes aegypti mosquito acquiring a blood meal from a human host.​

Last year, there were 214 million cases of malaria worldwide with the mosquito-borne disease killing 438,000 people, most of them in sub-Saharan Africa. Jo Lines, reader of malaria control and vector biology at the London School of Hygiene and Tropical Medicine, praised the idea behind the soap, but said it would be dangerous to rely on an untested product to protect against malaria.

As a social startup, Langevin said Faso Soap has struggled to attract funding from donors, including the World Health Organisation (WHO) and United Nations children's agency (UNICEF), prompting the inventors to turn to crowd funding. World leaders committed to ending malaria by 2030 when they adopted the Sustainable Development Goals last year. Europe last month became the first region to be declared malaria-free after reporting no indigenous cases in 2015, and a former WHO official said the world can eliminate the disease soon, but only with more investment to end and keep it at bay.

Mosquito-repellent Soap Invention Seeks to Fight Malaria in Africa
Global warming Not Expected to Boost Malaria in West Africa...

Study: Climate Change Not Expected to Boost Malaria in West Africa
July 18, 2016 - Our climate is changing. And it is having significant effects on the world around us. From threats of extinction for many species to cities submerged in rising ocean waters, there are many concerns. But one important effect often gets lost in discussions of climate change’s impact: disease transmission. A new study, in Nature Climate Change, models the long-term effects of climate change on malaria transmission in West Africa. And for once, the results aren’t all bad.
A necessary evil

In West Africa, subsistence farming relies on the regional monsoons. These heavy rains, combined with the flat landscape, also provide female mosquitoes ample puddles where they can lay their eggs. The temperatures are also just right for the mosquitoes to live a full life -- two months during which they can bite people and pass on parasites, including the plasmodium parasite which causes malaria. The location of water pools after monsoons is the driving process for malaria transmission in West Africa. Arne Bomblies, now an associate professor at the University of Vermont, painstakingly measured the temperature, location and size of these pools during his graduate work, enduring the heat and the nausea associated with malaria prevention pills.


Researcher and field assistant taking measurements on a puddle in Zindarou, southwestern Niger.​

For her graduate work, Teresa Yamana incorporated Bomblies’ hydrological data into models that combined the best West African climate predictions, mosquito behaviors and detailed information about the land. “We really look into a lot of detail. It’s not just amount of rainfall that matters it’s when it happens and what is the pattern of rainfall and how do these relate to the specific water pools that mosquitos need to breed,” Yamana, now a postdoctoral researcher at Columbia University, tells VOA. Most models that look at the climate effects on malaria transmission do not take into account the water pooling characteristics of the regions. They also mostly focus on the short term effects over a decade or so. The model Yamana developed predicted the burden fifty years from now. And the results were optimistic. The combination of temperatures warming to levels higher than those beneficial to mosquitoes and lower amounts of predicted rainfall act to maintain or decrease the malaria burden in West Africa.

Determining the malaria burden elsewhere

Bomblies and Yamana both hope that this process of including the hydrological characteristics of a region into malaria transmission models will be used elsewhere, although they note that the models cannot be used ‘as is’. They would need to be adapted to the terrain, mosquito ecology and hydrology of the region of interest. And this would be complicated for regions such as East Africa. Malaria burden is of particular concern in East Africa. The worry is that rising temperatures will cause malaria to spread into regions where previously, it was too cold for mosquitoes to breed. Andrew Githeko, a research scientist at the Kenya Medical Research Institute in Nairobi, tells VOA that the complicated topography of East Africa would require a significant change to the models before they could be used in this region. Andy Morse is a professor of climate impacts in the School of Environmental Sciences at the University of Liverpool. He stressed to VOA that this study predicts a reduction in the malaria burden in West Africa over the next 50 years, a much longer period of time than most studies. So he says regional authorities should still continue their attempts to control and prevent malaria transmission.


The monsoon season in West Africa usually occurs between May and October, though recently it has gotten more difficult to predict.​

Although the long-term outlook appears optimistic, Yamana and Bomblies point out that climate change will have many other impacts on the region. Bomblies notes that food scarcity is the utmost concern of people in West Africa. During his fieldwork, a serious famine caused a food shock there. This illustrated to him just how vulnerable the people of West Africa are to these changes in rainfall, which his models predict are going to decrease in the future. “While it might be sort of good news that malaria isn’t going to get worse in West Africa,” he cautions, “it by no means, means that there’s going to be no issue with climate change in West Africa.”

Study: Climate Change Not Expected to Boost Malaria in West Africa
Usin' chickens to ward off malaria mosquitoes...

Malaria Mosquitoes Repelled by Chickens
July 21, 2016 - If you live in sub-Saharian Africa in a malaria endemic area, it might not be such a crazy idea to sleep next to a chicken. It turns out some mosquitoes are repelled by the odor of chickens, potentially offering another cheap protection method against the mosquito-borne illness.
Most mosquitoes, including those that carry the often-deadly malaria parasite, like to bite humans. They transmit the disease through a blood meal. They also take blood meals occasionally from cattle, goats and sheep. But they are selective feeders. Mosquitoes don’t like the taste of chicken blood, so poultry rarely gets bitten. Swedish researchers made the discovery in field studies in Ethiopia. They set up traps to capture the most common mosquito in the area, Anopheles arabiensis, in 11 houses in Addis Ababa. Investigators then tested the blood inside the mosquitoes, finding blood from all sorts of animals. But rarely was there any blood from chickens.


Studies have found that mosquitoes don’t like the taste of chicken blood, so poultry rarely gets bitten.​

That begs the question: Should people in malaria endemic regions sleep next to a chicken? It’s a joke that Rickert Ignell hears all the time. “Oh yes. We do that all the time [make jokes] ... and the joke is also that people should carry a chicken around to protect themselves against malaria. But it hasn’t really caught on.” Ignell is a professor at the Swedish University of Agricultural Sciences, interested in studying the chemical attraction of disease-carrying insects, including malaria mosquitoes.

In those 11 houses, Ignell recruited 11 volunteers to sleep under untreated bed nets with traps, baited with chicken compounds, nearby. According to Ignell, “One of the tests we did was to actually suspend a chicken next to the traps that we used. And we actually saw about a 95 percent reduction in the trap capture. Indicating that chickens and chicken odors alone could actually repel the mosquitoes from the houses.”

Chicken feathers

Ignell said the odors that were offensive to the mosquitoes came from compounds in the chickens’ feathers. The compounds are cheap and some are already available. The idea of keeping a chicken inside a house to ward off malaria mosquitoes is not such a bad idea. “Many places in Ethiopia and many places in Africa that we’ve been working in, people actually keep their livestock indoors. Not often the chickens, but that is certainly something one could try to see if it works or not,” Ignell said. Ignell said the chicken method of insect repellent would have to be in combination with insecticide-treated bed nets for fuller protection.

Protection inside and out

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