Legacy of DDT

-DDT was first made in a German laboratory in 1874, but it's ability to kill insects was not test until 1939.

-DDT was put to use during WWII to combate foreign diseases carried by insects.

-After its success during the war, foreign governments were encouraged to institute the use of DDT (it was proven effective against anything with six or eight legs).

-Cheap and easily synthesized.

-By 1972 it was shown to cause extensive collateral damage to wildlife (i.e. songbirds & raptors). This lead to a strict ban of DDT in the United States.

-In 2006, the World Health Organization announced that the use of DDT would be reinstituted in the fight against Malaria.

Malaria Facts

-Malaria is a mosquito-borne disease caused by a parasite.

-Common symptoms are fever, chills, and flu-like illness. Left untreated, these may develop severe complications and die.

- Each year 300 million people are infected with Malaria

-3 million people are killed each year due to Malaria

- 41% of the world lives in areas where Malaria is transmitted.

-Transmission:

     -After a single sporozoite (the parasite form inoculated by the female mosquito) of Plasmodium falciparum invades a liver cell, the parasite grows in 6 days and produces 30,000-40,000 daughter cells (merozoites).

     -Merozoites are released into the blood when the liver cell ruptures.

     -In the blood, after a single merozoite invades a red blood cell, the parasite grows in 48 hours and produces 8-24 daughter cells, which are released into the blood when the red blood cell ruptures.

Prevention and Control of Malaria

-Vector control methods

• Fogging or area spraying with insecticide
• Personal protection measures
  • DEET
  • Insectiside-treated bed nets
• Indoor residual spraying
  • coat walls and other surfaces of the house with residual insecticide
  • Does not prevent people from being bitten, but kills the mosquitos after they have fed
  • Effects last for a couple months
• Source reduction (larval control) 
  • Apply insectides directly to larval habitats
    • Apply oil to the water surface
    • Introduce bacterial agents to kill them
    • Introduce insect growth regulators (Methoprene)
    • Introduce mosquito fish which eat the larvae

www.cdc.gov/Malaria/control_prevention/vector_control.htm#itn

Health Problems Associated with DDT

According to the Agency for Toxic Substances and Disease Registry, exposure to DDT can have negative effects on the nervous system. Long term exposure to smaller amounts affect the liver. It is potentially carcinogenic, and can be passed through breastmilk.

"It kills the bugs in the apple tree, I eat the pie and it's killing me. DDT on my brain, on my brain."

-Malvina Reynolds

Regulations of DDT

The Occupational Safety and Health Administration (OSHA) has set a limitation of 1mg of DDT per cubic meter of air in the work place for an eight hour shift, 40 hour work week. 

DDT Resistance

There are over 125 mosquito species with documented resistance to one of more insecticides. By 1972 when the U.S. ban of DDT came into effect, there were 19 species of mosquitos capable of tranmitting malaria that were also resistant to DDT.

Useful Links:

Malaria Foundation International

www.malaria.org

Africa fighting malaria

www.fightingmalaria.org