1 / 12

Malaria, Mosquitoes, and DDT The Toxic War Against a Global Disease

dana
Download Presentation

Malaria, Mosquitoes, and DDT The Toxic War Against a Global Disease

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. Malaria, Mosquitoes, and DDT The Toxic War Against a Global Disease By:Anne Platt McGinn

    2. Malaria In a Single Year 300-500 million cases of malaria 1-3 million people will die Majority women and children Competitor with AIDS, however very low priority Only 5% ($150 million) of the $12.8 billion funding that AIDS receives

    3. Malaria Process Caused by 4 protozoan parasite species. Female mosquitoes bite humans. Parasites moves from the saliva of mosquitoes to human blood. (sporozoite) Invades body’s immune system and makes way to liver (less than an hour). (merozoites) Moves from liver back into blood invading the red blood cells, destroys red blood cells. Symptoms: convulsion, difficulty breathing, coma, death.

    4. Malaria Process cont. As parasite multiplies in red blood cells, produces gametocytes. Occurs when parasites moves back into the mosquitoes. Mosquitoes can ingest the gametocytes, by feeding on an already infected person. Causes more sporozoites to invade the mosquitoes salivary glands. Cycle begins all over again.

    5. History of Malaria 1897 British physician Ronald Ross proved mosquitoes carried malaria. T. Roosevelt recognized malaria and yellow fever as the most serious obstacles in the construction of the Panama Canal. Prior French attempt to build canal lost between 10,000-20,000 men to malaria/yellow fever. U.S. used mosquito netting, filled in/drained swamps. Prevention tactics worked: 1906- 80% of workers had disease 1913- 7% had disease.

    6. Prevention Only about a dozen anti-malarial in use. Instead of focusing on killing the parasite, policy focused on killing the mosquitoes that carried the malaria parasites. Dichlorodiphenyl Trichloroethane (DDT).

    7. The Beginning of DDT 1939- Swiss Chemist Paul Muller discovered DDT as a potent pesticide. First used in World War II. Cheap and long lasting. Most insecticides stopped working after a few days. DDT lasted up to 6 months.

    8. The Beginning of DDT cont. 1955- World Health Organization (WHO) launched “Global Malaria Eradication Program.” 65 nations joined the cause. Funding for DDT factories donated to poorer countries. DDT production increased greatly. 1961- Program reached peak. Malaria eliminated/dramatically reduced in 37 countries.

    9. Impacts of DDT 1962- “Silent Spring,” by Rachel Carson published. Explained ecological damage caused by the widespread use of DDT and other pesticides.

    10. Process of DDT Exposure Bioaccumulates. Animal ingests DDT by eating vegetation contaminated with DDT. Pesticide collects in the animals fat instead of being excreted. Larger animal eats the infected animal, and the larger animal absorbs its prey’s DDT. Process leads to increase of DDT in higher animals in food chain. DDT’s high chronic toxicity leads to various physiological abnormalities.

    11. Previous Attitude Towards Malaria and DDT Main focus was getting rid of Malaria and not the toxicity of DDT. Eventually resistance occurred. Continual exposure to insecticide leads to a new breed of insect populations that are partially immune to the poison. DDT resistance occurred from 4-7 years. Took 3 years to clear malaria from human population. 1969- Campaign was abandoned.

    12. Current Attitude Towards DDT DDT resistance still very widespread. Finally recognized DDT will not prevail against mosquitoes. Most countries have banned this chemical. Finally asked the question: “In order to control disease why must we poison our soils, our waters, and ourselves?”

    13. Questions?

More Related