UN photo showing a mother and child protected from mosquito-borne disease by a bednet, the chief tool used in 2015 to prevent malaria transmission in endemic areas.
Just ten nations still used DDT in 2015, putting the planet on target to phase out all DDT use by 2020.
World Malaria Report 2015, published by the World Health Organization (WHO) in early December, notes those nations reporting that they use DDT in public health fights against disease. Under the Persistent Organic Pollutants Treaty, any nation may use DDT simply by notifying WHO. Signatories of the treaty usually agree to stop all use of DDT once current use ends. Since 2003, most nations using it found DDT simply didn’t work well enough to continue use it to fight malaria or any other vector-borne diseases.
In the 2015 Report, Appendix 2A lists methods of vector control used in nations (“vector” being the fancy word for carrier of the disease, or mosquitoes in the case of malaria). (See pages 234 to 237 of the .pdf.)
Nations in which DDT is used to fight malaria
World Malaria Report 2015 Appendix 2A
- Democratic Republic of the Congo
- South Africa
Ten nations total, nine in Africa, plus India.
Despite political calls to “bring back” DDT as a means of fighting mosquitoes that carry the Zika virus, no reports show any nation notified WHO it would do so. Most nations afflicted by Zika have been earlier afflicted by other diseases carried by the same species of mosquito, Aedes aegypti. This species carries dengue fever, yellow fever and chikungunya, and perhaps others. Consequently, most of these nations have already tried DDT against the Zika carriers, and abandoned the projects when hoped-for results did not occur.
Every mosquito on Earth in 2016 carries at least a few of the alleles that make them resistant to, or even immune to DDT. DDT use also pushes mosquito populations to develop paths that make them quickly resistant to other pesticides. WHO guidelines urge public health officials never to use just one pesticide, but instead rotate among a dozen approved for vector use, in order to prevent the bugs from developing resistance. Resistance to pesticides remains one of the chief obstacles to eliminating disease, and a growing obstacle.
India is the world’s only known maker of DDT in 2015, and the heaviest user, using more of the pesticide than all other nations combined. Due to decreasing effectiveness of DDT as mosquito resistance to to it spreads and grows stronger, malaria has proliferated in India despite increased DDT application. In 2015, India announced to WHO it would suspend manufacture and use of DDT by 2020.
In black, the ten nations who used DDT in 2016, nine in Africa, and India. 43 nations used DDT in 2001. India pledges to stop manufacturing DDT by 2020. Map by Ed Darrell, using Mapchart.net