In Africa, the malaria epidemic continues to be the cause of severe economic and physiologic distress amongst its populace. Those afflicted with the disease suffer from such symptoms as “severe chills, high fever, sweating, headache, muscle pains, vomiting, severe anemia, pulmonary edema, and many other complications”1 Infected red blood cells adhering to endothelium in capillaries of the brain can cause neurologic complications. The individual may develop cardiovascular collapse, shock, coma, and death1. Pharmacologic interventions and non-pharmacological measures (like mosquito nets) can prove to be very effective, but unattainable due to economic reasons. As a result, infected individuals may suffer long and painful deaths. A chemical pesticide known as dichlorodiphenyltrichloroethane (DDT) has proven to significantly decrease the incidence of malaria, but many argue that the harmful effects that DDT has on the environment and human health do not outweigh the benefits of fighting the malaria epidemic that has struck at-risk nations.
While DDT has been found to be effective in treating homes in the form of indoor residual spraying, it has destructive effects on the environment, as well as human beings. DDT’s effects on people include “increased risk of diabetes, impaired reproduction, and adverse effects on childhood neurodevelopment”2. During World War II and up through the 1960s, it was used as a large scale pesticide. Its long-lasting effects on the environment caused great concern amongst environmentalists and scientists, who then called for its eradication.3 Rachel Carson, an environmentalist, famously wrote a book about the pesticide entitled Silent Spring. The book “meticulously described how DDT entered the food chain and accumulated in the fatty tissues of animals, including human beings, and caused cancer and genetic damage”4. Carson is famously quoted from Silent Spring saying,
“How could intelligent beings seek to control a few unwanted species by a method that contaminated the entire environment and brought the threat of disease and death even to their own kind?”5
Carson’s work ultimately helped to pioneer the movement for its official ban. DDT has been linked specifically to quadrupling the chance of liver cancer development8 and its use is currently banned in the United States9.
However, could the benefits outweigh the risk? DDT is a generally inexpensive pesticide, and is thus more accessible to Africa’s population. It is sprayed in homes, and thus protects dwellers from mosquitoes. Malaria Foundation International states that “very few (probably no) human deaths or illnesses have been conclusively linked to proper usage of DDT. On the other hand, proper usage of DDT has prevented many illnesses and deaths that would have occurred as a result of malaria”6. Sadasivaiah, Tozan, & Breman state that “with proper regulation and management of the use of DDT in the public health vector, its illicit use in agriculture and the potential adverse effects on human health and the environment can be minimized”3. It is possible that much of the research about negative impact of DDT is from its usage as a large-scale pesticide outdoors. According to the World Health Organization, 3.2 billion people are at risk of malaria. This leads to about 198 million malaria cases (uncertainty range: 124 million to 283 million) and an estimated 584,000 malaria deaths”7. With these statistics many say that the benefits of DDT use outweigh the risk. However, the risks of DDT include blood contamination, which can lead to cancers of the breast and liver, to name a few. A study done in the US in recent years found DDT in the blood of 99% of those tested by the CDC, 40 years after it was banned.9 These numbers are significant when weighing the risk to the environment and humans to the risk of malaria.
With research advocating for both eradiation and support of DDT usage in countries in which malaria is a concern, the proper solution remains up in the air. Do we advocate for the environment and for potential health risks of DDT, or for the elimination of a deadly disease? Though healthcare professionals, environmentalists, and others remain torn on the subject, the cure for the malaria epidemic remains a priority, and what must be found is to eliminate the distress that it causes at-risk nations.
Picture from wikipedia and Fox News
8CancerConnect.com. (2015). DDT exposure linked to increased rates of liver cancer. CancerConnect.com. Retrieved from http://news.cancerconnect.com/ddt-exposure-linked-to-increased-rates-of-liver-cancer/.
5Carson, R. (1962). Silent spring. Boston: Houghton Mifflin.
6Malaria Foundation International. (2015). Is DDT still effective and needed in malaria control? Malaria Foundation International. Retrieved from http://www.malaria.org/DDTcosts.html.
1McCance, K.L. & Huether, S.E. (2014). Pathophysiology: The biologic basis for disease in adults and children (7th ed). St. Louis: Elsevier Mosby.
4Natural Resources Defense Council. (2013). The story of Silent Spring. Natural Resources Defense Council. Retrieved from http://www.nrdc.org/health/pesticides/hcarson.asp.
9Pesticide Action Network North America. (n.d.). The DDT story. Pesticide Action Network. Retrieved from http://www.panna.org/issues/persistent-poisons/the-ddt-story.
3Sadasivaiah, S., Tozan, Y., & Breman, J.G. (2007). Dichlorodiphenyltrichloroethane (DDT) for indoor residual spraying in Africa: How can it be used for malaria control. The American Society of Tropical Medicine and Hygiene, 77(6), 249-263.
2Whitworth, K.W., Bornman, R.M.S., Archer, J.I., Kudumu, M.O., Travlos, G.S., Wilson, R.E. Longnecker, M.P. (2014). Predictors of plasma DDT and DDE concentrations among women exposed to indoor residual spraying for malaria control in the South African study of women and babies (SOWB) Environmental Health Perspectives, 122(6), 545-552.
7World Health Organization. (2015). 10 facts on malaria. World Health Organization. Retrieved from http://www.who.int/features/factfiles/malaria/en/.