DDT's impact on public health and environmental policy

DDT: A Controversial Look on the Impact of Public Health

All research regarding the use of DDT confirms that it is an effective tool in the fight against the propagation of malaria. At the same time, DDT presents a variety of drawbacks, which we will examine below. It has been widely demonstrated that DDT is harmful to a variety of environments and ecosystems. The misconception therefore exists that DDT is an injurious chemical that strictly yields negative consequences. In fact, DDT has proven to be effective in fighting and containing the spread of malaria, insofar as its application is closely monitored when it is sprayed over large areas. Also, it is not recommended that DDT be used as the solitary response in fighting the spread of malaria. Ultimately, DDT provides many benefits with respect to combating malaria when deployed correctly.

Malaria has wide-ranging effects on human populations in terms of health, mortality and economics. It is transmitted to humans by way of four different types of parasites, typically found in Africa, Asia and Latin America. Direct transmission of the disease most often happens through lesions that occur from bites by female mosquitoes. Temperature and humidity are environmental factors that play a significant role in the transmission of malaria. Temperatures that fall below 60 degrees Fahrenheit inhibit the development of the parasites contributing to malaria. Additionally, deforestation has been demonstrated to increase the spread of malaria, by raising temperatures and eliminating natural environments in which mosquitoes typically inhabit, causing them to seek out human populations. More than one million people die each year from malaria. The majority of these fatalities are young people, and most deaths occur in Africa. Death rates associated with malaria indicate that roughly 3,000 children die everyday from malaria (Davis, 1971).

DDT was developed in 1874 with no specific usage at the time. It gained widespread use in the 1950s to control diseases such as malaria and as an insecticide. A multilateral effort known as the Global Malaria Eradication Campaign was initiated in the 1960s to fight the spread of malaria. Eventually, malaria was eliminated in most developed nations and in many sub-tropical nations where the disease had once been pandemic. However, most African nations failed to benefit from the effort to eradicate malarial infection, and DDT continued to be the primary resource in combating its propagation.

DDT, also known as dichloro-diphenyl-trichloroethane, has also been employed on farms and in agricultural settings to spray large plots of land as an insecticide since the 1950s. Over time, however, scientists began to observe the harmful effects of long-term use of DDT, with many developing the belief that it was toxic in large amounts. DDT is a compound that breaks down very slowly over time because of its low solubility to water. At the same time, DDT is very soluble in organic tissue, making it susceptible to absorption by living organisms. Among the primary concerns regarding DDT is the potential threat it poses to wildlife. Many nations banned the use of DDT during the 1970s following the lead of the U.S., who outlawed its use in 1973. In various research studies, DDT was determined to be a carcinogen, posing specific risks for causing liver and breast cancer. It has also been described as injurious to animal species, primarily bird populations. Studies conducted during the 1960s suggest that long-term application of DDT poses risks for the thinning of bird shells. This leads to premature births which, when experienced over many years, can lead to substantial population decreases (Graham, 1996).

During the 1960s, many environmentalists spoke out regarding the negative consequences of using DDT. Among them were the famed biologist Rachel Carson, whose 1962 book entitled Silent Spring suggested that DDT was toxic to small animals such as various species of fish and birds. The Environmental Protection Agency (EPA) was established in 1970 and ultimately was able to restrict, and then ban, the use of DDT as an insecticide. Carson further proposed that DDT was causing cancer in children, an accusation determined to be false by the EPA. By the mid 1990s, the United Nations advised nations against the use of DDT, and even imposed economic restrictions on those countries continuing to use it. However, they stopped short of banning its use.

However, findings in recent decades suggest that the harmful effects of prolonged DDT use to animal and human populations have been overstated. Experiments that incorporate regular and controlled consumption of DDT in bird populations indicated that there were no deleterious effects, such as thinning of egg shells or premature reproduction. Additionally, careful examination of bald eagle deaths during the 1970s found no correlation between prior DDT use and their fatality (Graham, 1996). This would suggest at the very least that, when DDT is used in a controlled setting, with close supervision and for a limited period of time, the chances of posing harmful effects on human populations are very low. Furthermore, studies of underdeveloped nations in which long-term DDT application has been unsupervised and rampant suggest a low correlation between DDT use and human health. When comparing this to the obvious and incontrovertible benefits of DDT use in fighting malaria, it is difficult to understand the position of the United Nations, who have imposed economic restrictions. The belief that healthy and highly supervised application of DDT to limited areas for the purpose of fighting this deadly disease poses far greater benefits than it does risks.

There is no insecticide that has been found to be more effective at controlling pest populations than DDT. It is therefore very tempting for countries to continue to use it, especially in sparsely populated regions. There is also no vaccine that fights malaria. It was eliminated in most developed nations prior to being banned and before being restricted by the United Nations. Many DDT advocates feel as though it is unscrupulous to declare it unhealthy subsequent to using it to effectively eradicate it. Most travelers to nations that still experience high rates of malaria are advised to fight it using prescription drugs, which should be taken for two weeks prior to arriving in the undeveloped country. Also, travelers should wear insect repellent at all times on exposed skin, and wear long-sleeved shirts and pants whenever possible. It should also be remembered that malaria can be absent in a human population, though it is still possible to contract the disease. Humans generate a certain resistance to disease after long-term exposure that newcomers would not have.

Ultimately, DDT is far more effective than any other protection against malaria, which is why it is still used today in many underdeveloped nations. It is widely believed by epidemiologists today that the most beneficial and cost-effective way to combat the spread of malaria is to spray inside of buildings. DDT can work in this case either by eliminating large mosquito populations or by repelling them from populated areas. Though mosquitoes have been found to have generated a resistance to DDT, they also tend to remain distant from human populations. It is worth noting that mosquitoes have also grown resistant to other types of insecticides, and that the primary parasite that leads to contraction of malaria has grown resistant to alternative prescription drugs. In addition, alternative medicines are more expensive, less effective and impossible to administer to large populations at once (Graham, 1996).

As an example of the cost-effectiveness of DDT, South Africa was the most recent country to ban its use.