Monday, January 12, 2009

Target Malaria

Malaria kills more than 1 million people each year. Most are children in Africa and Southeast Asia. African nations have set a goal of halving mortality caused by malaria on that continent by the year 2010, and the government of the Peoples Republic of China has taken steps to assist with managing malaria across its borders with Southeast Asian countries. These collective efforts face some significant health, environmental and political impediments. One of the focal issues is the use of the insecticide DDT as an indoor residual spray to control mosquitoes that vector the malarial disease-causing protozoan. Some suggest an increased use of the indoor DDT sprays, even in light of this chemical being banned by many governments because of its reportedly negative environmental and health impacts. This debate threatens to derail the progress of discussions and efforts to abate and prevent malaria.


  1. The gov.t needs to do all it can to stop the spreading of malaria. because if not controlled it could eventually spread to the u.s. and then it would be our problem.

  2. The treatment (more aptly the lack of treatment)in Africa amounts to genocide.

  3. Hello everyone, just a few thoughts that crossed my mind.Why do you suppose our gov't would ban DDT in the U.S. for health concerns on one hand and allow the export to other countries on the other? Is capatilism more important than the health of innocent people? Is the spread of malaria a greater threat to third world peolple or the long term effects of DDT? Is the lack of treatment in Africa genocide or population control?

  4. If we eradicated malaria by using an enormous amount of DDT here, could we not think about doing the same for Africa? If we go ahead and do that, some animals may be lost and some people may suffer ill effects, but would it not be worth it? A few could suffer now and save future generations from having the same problem. I know there would be a ton of people affected now, but it could be less than would be affected in the future.
    I looked up DDT and it is classified as "moderately toxic". I thought it was much more toxic than that, so I thought I should share that.
    Also, Dr. Gardner asked about why we care about malaria in Africa instead of other places. One of the facts that I found was that of the 250 million cases reported yearly, 90% were in Africa, most of those cases being children.

  5. What I've noticed as I've studied this tragedy more in-depth is that most of the futile efforts seem to be targeted towards treatment of the symptoms of the disease, rather than serious attempts at eradicating the source. While some believe that many people and the environment will suffer enormously from the effects of widespread spraying of DDT, there are some circles that believe Rachel Carson's claims have been widely discredited and that not one human has died from the effects of DDT. As a child, I was taken inside the house when the DDT trucks came into the neighborhood - and I'm still here -and I'm still not on any kind of medication, and I've never suffered any debilitating disease. Any environmental damage from DDT is reversible, as proven by the comeback of our birds. Please note - most strong environmentalists are also depopulationists - and as they continue to maintain a stranglehold on serious destruction of the malaria mosquito, millions and millions of people are dying - which amounts to some serious population control. Can anyone seriously imagine Americans putting up with 3,000 American children dying daily from this completely eradicable disease and being told to use mosquito nets and quinine? Gilbert Ross, M. D., writing in Health Facts and, wrote about it quite well: "Thanks to Rachel Carson's ode to a non-existent natural wonderland allegedly devastated by toxic pesticides, DDT became the target of the anti-chemical lobby, and its use was virtually abandoned - though late enough to spare the wealthy West from typhus and malaria. Left behind were the poor of sub-Saharan Africa and other tropical regions, and millions have paid the price for chemophobic ideologues who are themselves at no risk." The lack of a serious comprehensive effort at eradication of this disease is almost incomprehensible.

  6. When Jessica said that DDT is classified as "moderately toxic", I decided to look up the specific effects of DDT on humans. One interesting thing I learned is that in the 1950s, DDT was originally used to control lice, and people were unaffected even though they were in direct contact to DDT. On reason is that DDT has a hard time being absorbed through human skin. DDT is stored in fat cells of organs like adrenals, testes, and thyroid. This means if you are a nursing mother, you are directly nourishing your baby with DDT-spiked milk. Also, DDT can in fact be lethal for humans. At 236mg DDT/kg body weight, DDT is deadly. With only a fraction of that amount ( 6-10mg/kg body weight), DDT leads to symptoms like nausea, headache, vomiting, tremors, and confusion.

  7. I think Katie gives strong evidence that DDT should continue to be used. If we could supply nursing babies with alternate nourishment, I think that the effects of DDT would be a much better option than malaria, and would make a drastic eradication method worthwhile.

  8. Ok I'll play Devil's advocate,
    ** Most surveys put the U.S. alcoholism rate, the percentage of the population that is alcoholic or abusing alcohol, at around 7%(1). This means there are at least 20,000,000 alcoholics in the U.S. alone.
    **Number of alcohol-induced deaths, excluding accidents and homicides: 21,634
    **Number of alcoholic liver disease deaths: 12,928 Source: Deaths: Final Data for 2005, Tables 10, 23
    **There are approx. 200,000 homeless people in the U.S. on any given night,the majority being veterans.(Not very respectful of the people who we depended on for our FREEDOM!)
    **In the U.S. we have approx. 532,000 children in the Foster Care System.
    **It was estimated that in 2006 there were 1.6 million adult and 196,700 jeuvinile drug abuse violations in the U.S.
    **Approx 50% of all marriages will end in divorce.
    **In 2007 there were 11.25 million crimes of which 17,000 were murders.
    **Worldwide someone commits suicide every 40 seconds, 20 times that will attempt and fail.
    With all of that said, I can't afford gas for my car,I can't pay for the car because our economy is in recession, my home is in foreclosure,I might lose my job,statics show I may be a suicidal alcoholic drug addict about to get divorced, putting my kids in foster care and headed on a crime spree if I don't get murdered first.
    Why do I care about malaria in Africa?
    Don't forget Somalia! BHD

  9. Those of you who have posted have brought in some important thoughts on this topic. Matt Alderhold in his first post captured the ethical basis of this issue. Those questions underscore the dilemma of pesticidal exposure vs infection with the malarial parasite. Other posts have focused on DDT safety issues and the political morality of this controversy. As we move into the next phase of our discussions, keep all these points in consideration. But, also think on some additional points. First, is the argument against DDT actually coming from environmentalists? To answer this, consider the targeted use of the insecticide in these management programs. And, consider Katie's citations of DDT toxicity to humans. This issue is not so simple. The solution will involve moral issues and, thus, ethics. Post on, dudes!!!

  10. Well this is what I would do if I had all the power in the world AKA the president of the U.S.A.: first you get some cahones and start actually making so called changes. Then you tell your constituents "I am going to let the economy take care of itself, yes it will get bad people, but eventually it will fix itself and be better because of it(Yeah right! But giving a trillion dollars to failed institutions definitely isn’t fixing anything in the long scheme of things). Now I plan on taking a half of what we would spend on the stimulus package and I am going to solve a tragedy of human suffering. I want every spare medical professional and third and fourth year med student volunteers to come with me to Africa, the Middle East and Southeast Asia and Central and South America along with billions of bed nets, necessary antibiotics and pesticides, and a well planned strategy to control malaria.”

    Now of course this is an exaggerated dream but it is without a doubt in my mind possible, and probably a lot easier to solve than many other tragedies of our time. It has been done before in the southeastern U.S., so why hasn’t anyone had the compassion and intelligence to do what it takes because relatively it won’t take much. The showing of selflessness and caring will do an incalculable degree of improvement with our relations with the rest of the world not to mention the incredible amount of good karma that you can count on.

    Since malaria is spread by an infected person being bit by a mosquito your end goal must be eradication of the disease itself. The mosquitoes that vector the disease are only a problem because of the protozoans they drink along with their bloodmeal. So quarantine, in as nice a quarantine as possible for 550 million people, and give them the proper treatment and nutrition needed to cure the disease and to regain their health. While doing so you must also bring along a huge number of treated bed nets to give to the unaffected population and large amounts of DDT.

    Yes DDT. Yes it is dangerous to human health if exposure is long term. Yes it will destroy unintentionally other animals and harm the diverse ecology of beautiful Africa. But it’s the most effective pesticide and not to mention was the basis of the eradication plan the U.S. used in 1947. After eradication hopefully the lawmakers of the country will realize the value of their human population and ecology and will ban DDT. It only took the U.S. four years to eradicate malaria. Africa can handle a few more years of appropriately applied DDT to end a much more immediate and devastating problem. But why was America able to eradicate malaria while other countries continue to be crippled by it? Money!

    And who has the power to make money from thin air and use it for something so meaningful and morally awe-inspiring that they will be idolized as a hero to the entire world? The U.S.A. guided by the most influential leader in the entire known universe. Why will this never be accomplished? Who knows? Someone knows…not me, but I am just saying that it could happen!

  11. Well with all that said my position is very clear if we do not help Africa to somewhat degree then we as Americans will look even more heartless and selfish. (Methyl Bromide)

  12. Both Matt and Bob make very strong points also but we as a nation must come together and solve this problem.

  13. put this into perspective:if we can spend money on game shows, entertainment,and lunchboxes with Hanah Montana on them. even award large lump sums of money to random people to outsmart a 5th grader. then why cant we do something to stop milaria. millions of people are dying, and nobody seems to care. how does that make us look? if we could just put all that energy into something worth fighting for, we might be a force to be reconed with!

  14. I think the integrated management approach Dr. Gardner explained in class is the only way to control the further spread of malaria but a concerted large effort by first world nations will be the only way to make malaria extinct.

  15. As Wes mentioned above, I listed the components of the malaria eradication program: (1) attack the disease vector with household sprays of the long-residual pesticide DDT; (2) use mosquito nets over beds to prevent anopheline mosquitoes that are vectors of the disease from biting humans; (3) provide rapid diagnosis of malarial infection in the human population, and; (4) institute treatment of infected individuals with anti-malarial medicines (attacking the parasite within the human host).

    As several of you indicated, many factors impact the success of the program: availability of trained medical personnel, pesticides, anti-malarial drugs, rapid diagnostic kits, bed nets; accessibility of the area in terms of geography, government cooperation (or lack of), conflicts, etc.; literacy and cultural impediments; support of outside governments and private foundations.

    Many of you have made some very interesting and thought-provoking points both in class on on this blog. Our 2 visitors to the blog (Bob and Cowboy) also added some excellent points.

    Matt (A.) and Heather have agreed to lead the development of this first white paper on this issue. Wade in and provide additional input to your leaders. We will use the next class session to bring together a consensus of our collective thoughts on this ethical issue.


  17. well i guess it wont set up the link for me but it was the story about Bill Gates releasing mosquitoes on folks at a tech conference to bring attention to malaria, google it!

  18. There's a link on

  19. You can copy and paste the url's into your browser. The cnn story pops up.

  20. You know DDT is very effective in the extermination of mosquitos. But after years of use DDT has become resistant in some parts of the world like India, Pakistan, Turkey, and central America. So they have started using malathion and bendiocarb (organophosphate or carbamate insecticides) so the mosquitos cant get use to just one insecticide. These other insecticides are more expensive than DDT, and the malathion doesn’t stick well on some of the mud walls. There are some economic advisers that believe that 3 billion US dollars per year in aid could control the spread of malaria. The control of malaria would be great, but that 3 billion dollars could be very usefull right here at home, rather than thousands of miles away. We have enough problems here to worry about. Malaria needs to be controled but at what expense is it going to cost us? The US economy is in the sewer and it doesn’t look like it is going to get any better any time soon, we cant afford to help others when we cant even help ourselves!
    Bednets, preventive drugs, DDT, are all good methods for preventing the spread of malaria. Another common technique is pouring oil into standing water where mosquitos lay their eggs. In some labrotories, the Sterile insect-technique is being used for control. The scientists genetically modify the mosquitos that would have become infected if they were in the wild. This method cures only a small amount of the population and it isnt cheap. The reality is that until there is a cure for the disease the people that live in the infected regions will still be able to get malaria. The regions are very pour and some don’t even care if they get help.

  21. I agree that the money could be spent at home rather than in other countries. Just like the money spent on the never ending war in Iraq. We spend all of this money but what have we seen change since the beginning? If we spend all of that kind of money on Malaria, who is to say that anything will improve. Like Katie stated in class one day, we can spend all of the money and time, but if all of the people aren't willing to take the treatment then it is a waste of time and money! Don't get me wrong, I truly believe in helping others, but we have issues at home that need to be taken care of instead of trying to help those that aren't appreciative and cooperative!

  22. Ck out this site, good info.

    It gives all of the details, geography, biology,etc. of the Anthrophilic Anopheles Mosquito the primary vector of malaria.

  23. Here is the research material on the Pathogenesis and the references follow:
    Malaria in humans develops via two phases: an exoerythrocytic and an erythrocytic phase. The exoerythrocytic phase involves infection of the hepatic system, or liver, whereas the erythrocytic phase involves infection of the erythrocytes, or red blood cells. When an infected mosquito pierces a person's skin to take a blood meal, sporozoites in the mosquito's saliva enter the bloodstream and migrate to the liver. Within 30 minutes of being introduced into the human host, the sporozoites infect hepatocytes, multiplying asexually and asymptomatically for a period of 6–15 days. Once in the liver, these organisms differentiate to yield thousands of merozoites, which, following rupture of their host cells, escape into the blood and infect red blood cells, thus beginning the erythrocytic stage of the life cycle.[54] The parasite escapes from the liver undetected by wrapping itself in the cell membrane of the infected host liver cell.[55]
    Within the red blood cells, the parasites multiply further, again asexually, periodically breaking out of their hosts to invade fresh red blood cells. Several such amplification cycles occur. Thus, classical descriptions of waves of fever arise from simultaneous waves of merozoites escaping and infecting red blood cells.
    Some P. vivax and P. ovale sporozoites do not immediately develop into exoerythrocytic-phase merozoites, but instead produce hypnozoites that remain dormant for periods ranging from several months (6–12 months is typical) to as long as three years. After a period of dormancy, they reactivate and produce merozoites. Hypnozoites are responsible for long incubation and late relapses in these two species of malaria.[56]
    The parasite is relatively protected from attack by the body's immune system because for most of its human life cycle it resides within the liver and blood cells and is relatively invisible to immune surveillance. However, circulating infected blood cells are destroyed in the spleen. To avoid this fate, the P. falciparum parasite displays adhesive proteins on the surface of the infected blood cells, causing the blood cells to stick to the walls of small blood vessels, thereby sequestering the parasite from passage through the general circulation and the spleen.[57] This "stickiness" is the main factor giving rise to hemorrhagic complications of malaria. High endothelial venules (the smallest branches of the circulatory system) can be blocked by the attachment of masses of these infected red blood cells. The blockage of these vessels causes symptoms such as in placental and cerebral malaria. In cerebral malaria the sequestrated red blood cells can breach the blood brain barrier possibly leading to coma.[58]
    Although the red blood cell surface adhesive proteins (called PfEMP1, for Plasmodium falciparum erythrocyte membrane protein 1) are exposed to the immune system, they do not serve as good immune targets because of their extreme diversity; there are at least 60 variations of the protein within a single parasite and perhaps limitless versions within parasite populations.[57] Like a thief changing disguises or a spy with multiple passports, the parasite switches between a broad repertoire of PfEMP1 surface proteins, thus staying one step ahead of the pursuing immune system.
    Some merozoites turn into male and female gametocytes. If a mosquito pierces the skin of an infected person, it potentially picks up gametocytes within the blood. Fertilization and sexual recombination of the parasite occurs in the mosquito's gut, thereby defining the mosquito as the definitive host of the disease. New sporozoites develop and travel to the mosquito's salivary gland, completing the cycle. Pregnant women are especially attractive to the mosquitoes,[59] and malaria in pregnant women is an important cause of stillbirths, infant mortality and low birth weight,[60] particularly in P. falciparum infection, but also in other species infection, such as P. vivax.[61]
    • ^ Bledsoe, G. H. (December 2005) "Malaria primer for clinicians in the United States" Southern Medical Journal 98(12): pp. 1197–204, (PMID: 16440920);
    • ^ Sturm A, Amino R, van de Sand C, Regen T, Retzlaff S, Rennenberg A, Krueger A, Pollok JM, Menard R, Heussler VT (2006). "Manipulation of host hepatocytes by the malaria parasite for delivery into liver sinusoids". Science 313: 1287–1490. doi:10.1126/science.1129720. PMID 16888102.
    • ^ Cogswell FB (January 1992). "The hypnozoite and relapse in primate malaria". Clin. Microbiol. Rev. 5 (1): 26–35. PMID 1735093. PMC: 358221.
    • ^ a b Chen Q, Schlichtherle M, Wahlgren M (July 2000). "Molecular aspects of severe malaria". Clin. Microbiol. Rev. 13 (3): 439–50. doi:10.1128/CMR.13.3.439-450.2000. PMID 10885986. PMC: 88942.
    • ^ Adams S, Brown H, Turner G (2002). "Breaking down the blood-brain barrier: signaling a path to cerebral malaria?". Trends Parasitol 18 (8): 360–6. doi:10.1016/S1471-4922(02)02353-X. PMID 12377286.
    • ^ Lindsay S, Ansell J, Selman C, Cox V, Hamilton K, Walraven G (2000). "Effect of pregnancy on exposure to malaria mosquitoes". Lancet 355 (9219): 1972. doi:10.1016/S0140-6736(00)02334-5. PMID 10859048.
    • ^ van Geertruyden J, Thomas F, Erhart A, D'Alessandro U (2004). "The contribution of malaria in pregnancy to perinatal mortality". Am J Trop Med Hyg 71 (2 Suppl): 35–40. PMID 15331817.
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  24. As a few people stated in class, cooperation of the African nations is key to the success of any treatment. We always think about the countries that have the most problems with malaria and how they will react to any kind of treatment, but what about the countries with a low incidence of malaria? They probably won't want to be exposed to DDT, but their cooperation is essential if malaria is really to be eradicated. If they refuse treatment, then a few mosquitoes there could start the whole thing over again, even if the areas with major incidence are treated successfully.
    I don't know if that really needs to go into the paper, I just thought I would mention it.

  25. Shouldn't we also include something about the fact that kelly and cam made about limited money supply and needing it in some other areas: Peoples lives are at stake in these maleria infected countries but there are some very important decisions to be made in the U.S. before we could have the money to deal with it or some serious support from "non-gov." coorperations/individuals. And also, if we did get the money, would we have to force DDT on some of the "less infected" countries(as some one said last monday in class)in order to completely eradicate it and not waste our money. Not sure if this is relevant material for the paper, but just an idea.

  26. Our discussions and our posts have helped in developing a very nice summary white paper on this issue of using DDT to control and eradicate malaria. (Thanks to our 2 guests who had some excellent points to add as well.) If you have not read the paper, please do so. You should find it as an attachment to an email that I sent to all of you. This will be distributed as a hard copy to the class on Monday, Feb 16th.

    Our discussions began to address the issue of funding. And, as we mentioned in our class discussions, money (and maybe a lack of sustained interest) ended the global eradication effort that began in the 1950s. Continuation of the program was left to individual countries. Without the means, for whatever reason, developing countries have not controlled this mosquito-borne parasite and the disease that it causes.

    You agreed that the disease should be targeted for eradication again, using the current program with its curative and preventive components. You also agreed that the human health risks associated with DDT exposure are outweighed by the benefits of eliminating malaria and that the debate of DDT use in the eradication effort should not slow program implementation.

    Unfortunately, the debate over DDT will likely not be the key issue that limits successful eradication. These factors will likely reside in governments, politics, corruption and graft, religious and cultural beliefs, literacy and education and, yes, even funding.