MALARIA ERADICATION AND DDT

MALARIA ERADICATION EFFORTS

20110306-malaria cdc  burrow_pit.jpg
ideal breeding area for mosquitos
In the United States in the mid-1930s over four million people came down with malaria. After World War II the disease was eradicated with effective mosquito control, namely the spraying of strong pesticides on standing water, medical treatment and an improved standard of living. More than three million acres of wetlands were drained, DDT was sprayed in hundreds of thousands of homes and screens were installed to keep the mosquitos out of houses. The United States was also fortunate in the fact that the most common form of malaria mosquito found there preferred cattle to humans.

Many hoped a similar program could eradicate malaria from the rest of the world. In the 1940s and 50s over 300 million cases of malaria broke out annually with one death from the disease occurring every three seconds, totaling three million a year. In some ways these figures are not much different from the malaria figures that we hear about today but remember back then the world population was about a third what it is now.

In 1955, WHO declared a global war in malaria. A worldwide malaria eradication program was set up by a man named Fred Soper, who according to some people saved more lives in the 20th century than any other single person. Soper's idea was to eliminate the malaria-carrying mosquitos long enough so they could no longer carry the parasites. He had great success eradicating malaria from malaria- infested areas in Brazil by running a disciplined program with flag-carrying, uniformed workers who systematically reduced areas of standing water; sprayed homes and cars with insecticide; and set up road blocks to make sure malaria did not spread.

Websites and Resources on Health and Diseases: Centers for Disease Control and Prevention cdc.gov/DiseasesConditions ; Disease Pictures hardinmd.lib.uiowa.edu/pictures ; World Health Organization (WHO)statistics and data who.int/research ; World Health Organization (WHO) disease outbreak alert who.int/csr/disease ; Third World Traveler thirdworldtraveler.com/Disease/diseases ; Health Map healthmap.org ; Medline Plus medlineplus/healthtopics ; Merch Manuals (detailed info many diseases) merckmanuals.com/professional/index ; Health Images Directory healthline.com/directory/images

Malaria Eradication Methods

20120531-Malaria DDT3px-Chapter_8.2_Image_2.JPG
Malaria thrives in tropical areas where the climate is right for the specific mosquitos that carries the disease and there is a lot of rain and stagnant pools of water for mosquitos to breed. Pools that are 10 meters to 20 meters across are regarded as the biggest problem. Smaller pools dry up and larger, permanent ponds are home to predators such as larvae-eating beetles.

Mosquitos bite mostly at night when people are sleeping. One cost-effective preventive measure is applying small amounts of insecticide on walls where mosquitos like to linger.

Malaria is appearing in a number of highland areas of Africa that had traditionally been too cold for the malaria mosquitos to thrive. Global warming is blamed.

Health officials say if all tools---such as nets, medicines and DDT---are utilized the number of malaria cases could be reduced by 90 percent. But getting rid of the last 10 percent is a tall order. Some countries such as Saudi Arabia, South Africa and Mexico have come close to eradicating its but were unable to stop the spread of the disease from coming in neighboring countries (Yemen, Mozambique, Guatemala). Poverty and warfare are two obstacles that need to be overcome. Many argue the goal of complete eradication is unrealistic, invites frustration and requires enormous amounts of money that could be better spent on other diseases or problems.

Malaria Eradication and DDT

20110306-malaria cdc  fogging.jpg
fogging
A hallmark of the malaria eradication program was the spraying of houses and to a lesser extent malarial swamps in afflicted areas with DDT. In the late 1950s tons of DDT was shipped out all over the world and institutes were set up to teach people how to administer it. In India, alone, 150,000 people were hired. By 1960s, 60 nations were signed up to take part.

DTT (dichloro-diphenyl-trichloroethane) is an odorless white crystalline powder invented in 1874 in a German laboratory for no particular reason and shelved and forgotten. In the late 1930s, Paul Müller, a chemist for the Swiss drug company J.R. Geigy, was searching for a new way to protect woolens against moths. As he did with hundreds of other chemicals he placed DDT in a glass box filled with flies. The flies didn't die immediately but within 24 hours they were all dead. He also found that DDT kept killing for months and after the glass box had been cleaned with powerful chemicals. In 1948, Müller won the Nobel prize for his work.

Later experiments found that ducks who carried DDT from a DDT-treated pond to an untreated pond carried enough DDT to kill all the mosquitos and mosquito larvae in that pond. Test were also done that showed people who slathered themselves with it suffered no harmful effects. After World War II, DDT was used to get rid of mosquitos in campaigns against yellow fever, dengue fever and other diseases as well against malaria.

Success of DDT

20120531-Malaria_spraying_sign.jpg
DDT lasted twice as long as he next best insecticide and was one forth the price. In the early years, the result of the malaria eradication program were dramatic. Malaria was eradicated from South Korea and Taiwan, much of the Caribbean, Italy, the Balkans, parts of northern Africa, the northern region of Australia, and much of the Pacific. The disease was nearly wiped out in South Africa, Mozambique, Sri Lanka, India and large areas of Southeast Asia. In all these places extensive spraying with DDT was done.

A DDT campaign in Sri Lanka reduced the number of confirmed cases of malaria there from 2.8 million a year in the 1950s to 17 in 1963. In India, where 150,000 workers were put to work spraying homes, fatalities dropped from around 800,000 a year in the early 1950s to near zero in the early 1960s. The number of cases dropped in the same period from 75 million to 50,000.

In 1970s the National Academy of Science reported that “to only a few chemicals does man owe as great debt as to DDT. According to some estimates DDT in conjunction with chloroquine---which was widely distributed during the DDT campaign---saved tens of millions of lives between 1945 and 1965.

Great strides were made in the eradication of malaria not through DDT use but also by making cheap and effective drugs, namely chloroquine, available. The number of cases worldwide is believed to have been reduced by two thirds to around 120 million case annually, with about 80 percent of these cases are in Africa.

Problems with DDT

20120531-Malaria DDT426px-Chapter_8.2_Image_1.JPG DDT also lasted along time, collected in fats and was passed up the food chain, which was good for mosquito killers but bad news for the environment. It was particularly devastating to birds that ingested insects killed with DDT. These bird produced eggs with abnormally thin shells and young with birth defects.

In some places spayed with DDT the birds disappeared completely. Their silence inspired the title of Rachel Carson's The Silent Spring , a book published in 1962 that not only brought an end to DDT use in many places but is regarded by many as the work that launched the environmental movement. The book detailed how DDT was passed up the food chain, harming robins, eagles, salmon and fiddler crabs.

Carson’s book failed to mention that DDT was also responsible for saving millions of lives. Later studies indicated that the main problem with DDT use in the 1950s and 60s is was that it overused. The damages describe by Carson was primarily the result of large scale agricultural use and spraying from airplanes. DDT used sparingly to spray houses is not that dangerous to the environment. The main problem was not the malaria eradication problems but its extensive use in agriculture, particularly by cotton farmers who tended to way overuse it because it was so cheap.

In 1972 DDT was banned in the United States. Many other developed countries also banned it. Africa and Asia were dependant in these countries to finance their anti-malaria programs, and when the developed countries banned DDT they stopped supporting it use in the developing world. Many think that if the DDT campaign continued malaria could have possibly been eradicated. In his book State of Fear , the writer Michael Crichton asserted that decision to ban DDT “has killed more people than Hitler.” One U.S. health official said the ban “may have killed 20 million children.”

Later History of Malaria Eradication

20120531-Malaria Mansprayingkeroseneoil.jpg
Man spraying kerosene oil
Despite all of DDT successes it could not eliminate malaria entirely and over time it became clear that of eradicating malaria was unrealistic. The DDT eradication program had success in some areas but failed to reduce the overall number of malaria cases. In sub-Saharan Africa and Amazonia it proved to be just too difficult to spray all the homes and clear out all the breeding areas for mosquitos. Lazy workers and corruption also presented problems and mosquitoes developed resistance to the insecticide.

In Africa, the eradication program never really got going. The WHO program largely bypassed the continent. Small programs made little progress.

By the early 1960s funding was running low and countries that had been told that malaria would be eradicated in four years but wasn't began putting money in other programs. In 1969, WHO abandoned the goal of global malaria eradication. In 1976, The program was officially declared a failure. During the 1980s funding for combating malaria dried up and by the 1990s the disease was largely ignored. In Africa, malaria control became such as low priority that some government employed only two or three people in their anti-malaria programs.

In the late 1990s, WHO launched another anti-malaria campaign with UNICEF, United Nations Development Fund and the World Bank. The aim was reduce the number of malaria deaths by 50 percent by 2010 by raising awareness, providing anti-malarial treatments such as drugs and insecticide-treated netting and identifying malaria hot zones.

Comeback of Malaria

20120531-Malaria spray Tandjoengpriok_West-Java.jpg
West Java
Malaria has made a comeback in North Africa, India, Southeast Asia, China, South America, and the Caribbean. Between the 1960s and 1990s, the number of cases of malaria in the Western hemisphere increased 13 times. During the same period the number of cases in India soared from 60,000 to 1.6 million. In Sri Lanka after the use of DDT stopped in the early 1960s, the number of cases increased from near zero to 1 million cases a year in 1970, just a few years later. By the time malaria began its comeback in the developing world it had essentially been eliminated from developed world and money and energy that had gone into combating and researching the disease had disappeared.

Many health officials say that if anything the malaria situation is getting worse. Studies have shown that mosquitoes are transmitting the disease more frequently, the number of breeding sites is increasing, and the areas affected are more populous. Not only are incidences of the disease increasing at alarming rates but mosquitos are becoming increasingly resistant to available drugs and malaria itself is more deadly. The disease can be particularly devastating when it reappears in an area that it was nearly eradicated was the case in Sri Lanka because malaria is more resistant to the body’s defenses and populations have less protective antibodies.

By some estimates the percentage of the world’s population exposed to Malaria increased from 40 percent to 50 percent between the 1990s and 2000s. Researchers believe the cases of malaria quadrupled in Africa in the 1980s. In the 1990s the mortality rates from malaria jumped 11 fold in the some areas of eastern and southern Africa. Urban areas in Asia that were once thought to be fairly safe from malaria no longer are. The disease is particularly prevalent around cities in India.

Reasons for the comeback of malaria have included the ending of DDT spraying and the increase of human practices---carelessly discarded tires and water bottles, footprints from livestock, water kept behind dams, even flower pots at cemeteries---which create still water and breeding grounds for mosquitos.

Global warming could cause increase the range of malaria-carrying mosquitos and cause them to bite more frequently. Malaria-carrying mosquitoes are already showing up in temperate areas and at high elevations perhaps because of global warming. Malaria has reappeared in the former Soviet Union. It took 50 years to eradicate malaria there and has taken less than five years for it to come back.

Comeback of DDT

20120531-Malaria Mumbai_street_2011_1630.JPG
Mumbai in 2011
Many health care advocates say it is time to bring back DDT primarily in the form of spraying small quantities inside houses, which has proved to be very effective getting rid of mosquitoes with few risk to people or the environment. Houses that have been sprayed with DDT have no mosquitos while unsprayed houses have hundreds of them. The spraying of houses with DDT has wiped out malaria completely in some places and dramatically reduced infant mortality in others. There are no plans to spray it from airplanes or use in pools of standing water. The same amount used to spray one cotton farm in the 1960 can be used on 450,000 homes. Only small doses are needed because the DDT is used to repel mosquitos rather than kills them.

DDT is still used in places such as China, India and Mexico to combat malaria. China and India are the only two places it is still manufactured. Many people want DDT to be brought back the disease in places were it isn't used. Not only is DTT effective it is also very cheap. Spraying a house with DDT costs between $1.60 to $8.50 compared to $4.20 to $24 for alternative, more environmentally-friendly pesticides such as pyrethroid, which are prohibitively expensive for most Third World countries. Moreover, mosquitos tend to become resistant to other pesticides quicker than they do to DDT.

DDT has made a come back in South Africa. The town of Ndumo, for example, experienced a serious malaria outbreak in 2000 in which more than 7,000 people showed up at a local clinic and the South African army had called in for help. By 2004, after the walls inside all houses in Ndumo were sprayed with DDT, the disease was largely gone. The use of DDT had been stopped in 1996 in part because of pressure from other nations and replaced with other insecticides. Mosquitos quickly developed a resistance to the new insecticides and malaria cases skyrocketed.

20120531-Malaria Mumbai_2011_1624.JPG
Malaria spaying in Mumbai
One of the ironies about DDT use is that was used to eradicate malaria in many places in the developed world such as the United States and southern Europe but is now denied to the developing world which still suffers terrible from malaria. Africa in particular relies on Western donors to support its anti-Malaria programs and these donors have been reluctant to provide money for DDT.

Critics of DDT use assert that mosquitos will become resistant to DDT and develop strategies to avoid it as they have in the past. They argue that yes DDT can be a useful tool in the fight against malaria but the time and place where it is used should be carefully considered and widespread use is not advised.

In 2006, the World Health Organization (WHO) urged developing countries, especially ones in sub-Saharan Africa , to use DDT as a cheap but effective means to fight malaria. It recommended coating the inside walls of mud huts and other dwellings to prevent mosquitos from biting people at night.

New Malaria Eradication Strategies

Researchers at Virginia Polytechnic Institute are developing pesticides that activate only inside mosquitos, posing no threats to humans or other animals. Scientists at Jerusalem Hebrew University said they had wiped out virtually every mosquito in an oasis in southern Israel by taking advantage of the mosquitos’s sweet tooth and placing a sugar solution with an insecticide on acacia trees.

Researchers at Columbia University are trying to block a mosquito’s sense of smell so that it can’t find human host to attack. Other scientists are trying to engineer lemon grass to repel malaria.

To better estimate the number of malaria cases in a given area scientists are relying more on satellite imagery that provides data on vegetarian, temperature, and humidity, which reveals information on areas that are at risk, which in turn can be combined with ground data and studies to determine how many people might get infected and or die.

Researchers at the Imperial Collage of London are trying to battle malaria by disrupted the sex life of mosquitos that carry it. In 2009 they announced they had found that the Anopheles gambaia, a species of mosquitos that transmits malaria in Africa, mate only once and they can disrupt their reproduction by mucking with the “mating plug” used by males to ensure their sperm stays in the female and not that of a rival. Without the plug sperm is not stored properly and successful reproduction does not take place. The scientists have found an enzyme that is essential for the production of the plug and are working on developing a way to block its production and put that in a spay that can be employed on a large scale.

20110306-malaria cdc  malaria_stamps.jpg

Scientists are discussing the merits of releasing malaria mosquitos that have been genetically altered so they don’t carry the disease. They idea is that they will mate with other mosquitos and their offspring would also be unable to carry the disease. The same concept can be used to tackle other mosquito-born diseases such as dengue fever.

One African species of mosquito is useful in the fight against mosquitos. They devour the eggs of other mosquitos but only feed on nectar and plant juices themselves.

Low-Tech Malaria Eradication Strategies

In the past mosquito eradication programs have centered around draining swamps and paving streets to get rid of potholes where mosquitos can breed. Low-impact methods that can achieve the same results include using shovels to fill in low spots were rain water can collect and digging drainage ditches that can empty standing pools in less than the seven to 10 days necessary for larvae to mature. Plowing the ground so water can more easily seep into the soil is also effective but more labor intensive. Another trick is scattering ground-up, neem tree seeds in ponds twice a week. This has been shown to reduce mosquito populations by half. Neem oil is use in the United States as a pesticide, for houseplants and is considered safe enough to use in dog shampoos.

Other low-cost alternative methods of combating malaria include breeding larvae-eating fish in ponds where mosquito larvae live, filling pits that collect standing water and planting moisture-sucking eucalyptus trees in marshy areas to get rid of standing water there

Some Mediterranean countries have had great success with mosquito-eating fish planted in still water areas with malaria mosquitos. In Africa and Southeast Asia, malaria-carrying mosquitos often breed in rice paddies. There, mosquito larvae can be killed if the water in the paddies is periodically emptied.

20120531-Malaria spray indonesia.jpg
Malaria spraying in Indonesia

Lack of Funding for Malaria

Malaria is the world's deadliest disease yet the amount of money spent on it---about $100 million a year on research, with about 25 percent coming from the United States, and $200 million a year on malaria control--- is minuscule compared to what is spent tackling lesser diseases that affect people in Western countries. The main reason for the lack of funding is that malaria is virtually non-existent in developed countries and it is regarded by drug companies as a poor man's disease with little potential for profit.

In Africa, AIDS gets much more attention than malaria in part because the disease is also a problem in the West and it tends to strike members of the African upper and middle classes while malaria primarily affects the rural poor.

For variety of commercial, legalistic and scientific reasons, pharmaceutical companies have turned down a proposal to form a consortium of profit-making and non-profit organization to do research into malaria and other tropical diseases.

Gates told The New Yorker magazine, “It just blows my mind how little money has been spent on malaria research. What has prevented the rich world from attempting this? I just keep asking myself. Do we really not care because it doesn’t affect us?”

20110306-malaria cdc  geodistribution2.jpg
where malaria is found

Gates Foundation and Malaria

As of October 2005, the Gates Foundation had pledges $150 million for malaria research with millions more form other Gates Foundation public health programs also going towards malaria. Entire malaria-fighting programs are supported by the foundations as are some far out methods that would never would never receive funding if they relied on traditional government sources. Among the grants given out by the Gates is $43 million given to a California biochemist to genetically-engineer bacteria to grow artemesinin.

Gates told The New Yorker magazine, “Human suffering as a result of malaria is incomparable. By many measures, its easily the worst thing on the planet. I refuse to accept it. I refuse to sit there and say, O.K. next problem, this one doesn’t bother me. It does bother me. Very much. And the only way for that to change is to stop malaria. So that is what we are going to have ro do.”

Gates’ generosity triggered a wave of support from other sources. The Bush administration pledged $1.2 billion over five years to fight malaria in Africa mainly in the form of providing mosquito nets treated with insecticide, distribution of effective medicines such as cocktails with artemisinin, and spraying houses with insecticides. When the announcement was made the New York Times editorial read: “The wonder is that it took so long. This ancient scourge is so deadly and pervasive, and effective remedies are so cheap, there is not justification for the world’s past indifference.”

In 2002, the Global Fund to Fight AIDS, Tuberculosis and Malaria was set up. Funded largely by the Gates Foundation and the U.S. government, it has approved $500 million for malaria, The World Bank plans to sped between $500 million and $1 billion on malaria over the next five years, US AID increased its funding for combating malaria from just $12 million in 1989 to $80 million in 2003.

Image Source: Centers for Disease Control and Prevention cdc.gov/DiseasesConditions ; Wikimedia Commons

Text Sources: CDC Health Information for International Travel, U.S. Department of Health and Human Services; National Geographic, New York Times, Washington Post, Los Angeles Times, Times of London, The New Yorker, Time, Newsweek, Reuters, AP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.

Last updated March 2011


This site contains copyrighted material the use of which has not always been authorized by the copyright owner. Such material is made available in an effort to advance understanding of country or topic discussed in the article. This constitutes 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner. If you are the copyright owner and would like this content removed from factsanddetails.com, please contact me.