When I first read about insecticide treated mosquito nets (ITNs), I did a double-take. Even if they prevent malaria, I reasoned, their toxic potential must be enormous. I imagined toddlers sucking on them, and the chemicals being released as volatile organic compounds on a humid, rainy African night. In the face of those risks alone, the benefits seemed negligible.
Further research has made me rethink that assessment. One of the most important findings - that the World Health Organization only approves bednets treated with permethrin - is a positive sign. Permethrin (and other pyrethroids, as they're known) are pyrethrin-based insecticides. Pyrethrins themselves come from plants, called pyrethrum, which are part of the Chrysanthemum family. Blooming in June in the Northern Hemisphere, these perennials produce brightly-colored flowers in shades of red and white, and planting them in vegetable gardens is known to deter pests. In fact, the plant's unique ability to act as a pesticide has been documented since the days of the Persian Empire, or about 300 B.C.
The second bit of information, however, is negative. These pyrethroids also contain the synthetic chemical piperonyl butoxide. Permethrin and similar pesticides are known as synergized pyrethrins, since the piperonyl works with pyrethrin to enhance its effectiveness. Piperonyl butoxide is highly potent, and this may be good in terms of insect eradication, but perhaps not so good for humans.
Piperonyl butoxide is a cytochrome P450 inhibitor, and affects the function of cellular proteins. Exposure can deregulate hormones, affect liver function (and reduce cholesterol synthesis), and inhibit vitamin D metabolism. It can also slow or degrade the body's ability to detoxify itself, allowing higher concentrations of toxic chemicals to remain in the body longer, thus increasing the risk for illness and disease.
Scientists suspect, but have so far been unable to prove, that piperonyl butoxide causes cancer, genetic mutations, or disfiguring and debilitating birth defects. They do know it is highly toxic to fish.
However, a larger picture shows that, worldwide, the death rate from malaria has fallen to about a million people every year, largely due to the use of insecticides. This is a great improvement from the 1940s when more than three million people perished from malaria every year, many of them in Sub-Saharan Africa. Children, because of their size, higher metabolisms and greater overall vulnerability, are the primary victims. Of one million victims worldwide, 800,000 will be African children, and these children can die within hours if the infection is severe.
Before the introduction of ITNs in 2002, the incidence of childhood deaths was twice as high in some areas as it is now. In India, the overall mortality rate has declined 40 percent since 2007. Clearly, ITNs are doing their job, though a large degree of success might also be due to ACTs, or artemisinin-based combination therapies, obtained from the sweet wormwood plant.
Artemisia, native to Eurasia and widely grown in China for centuries - where it is known as qinghao - shows great promise in interrupting calcium uptake in the parasite that causes malaria. Current treatments call for a 7-day dose of Artemisia in combination with other anti-malaria drugs, but advances in artemisinin formulation may reduce future dosing to three or four days, making it easier for inhabitants of third-world countries not only to remember to take a full dose, but to afford it.
The only concern scientists have about Artemisia is that continued use may cause the parasite to develop resistance, as happened in the case of chloroquine, which was successfully used for 50 years before the malarial parasite was no longer susceptible. However, scientists believe that timely and appropriate use may keep Artemisia in the malaria-drug pipeline at least through the middle of the century.
In Africa, where malaria is endemic, farmers have begun planting Artemisia in place of sorghum because the crop is highly profitable, and the plant - escaping patent by any major drug company due to its status as a native annual - is easy to grow. Locally-grown Artemisia also escapes some of the cost effects inherent in drugs which have to be processed elsewhere and shipped, since one of the key elements to effective malaria control in third-world countries is affordability.
ITNs remain the first line of defense against malaria, but they only have a three-year lifespan. After that, the chemical benefit wears off. Still, since the distribution of these ITNs began, under the auspices of UNICEF, the Global Fund, World Bank, and donors like CIDA and the Government of Japan, no epidemic-level outbreaks of malaria have occurred anywhere in the world.
Another line of defense in the battle to eradicate malaria involves IRS, or indoor residual (insecticide) spraying. The IRS programs, however, are more difficult to accomplish and pose greater risks, since inhabitants of malaria-plagued countries often can't read and do not disperse the chemicals per safety labels, or follow warnings for safe disposal of the containers. Nor do they always follow post-treatment protocols, which require staying out of the dwelling for a short time. IRS is also limited by the logistical and planning skills of the government agencies in question, and the amount and cost of the chemicals needed for successful implementation. After the failure of IRS programs using DDT and dieldrin in the 50s and 60s, many programs were abandoned. More recently, the programs have been resurrected, and many still use DDT, in spite of the associated environmental impacts.
The RBM (Roll Back Malaria) Partnership is one of the most important and prominent agencies in the effort to eradicate malaria, which kills more people worldwide than any communicable disease except tuberculosis. RBM is attempting to promote programs which provide the nets for free or under government-subsidized distribution programs. RBM, which boasts the Bill and Melinda Gates Foundation as one of its sponsors, is represented by eight countries, three donor countries, four developmental partners, and a significant number of representatives from the private sector, scientific organizations, and global aid groups.
Several enterprises make the ITNs, including NetMark (whose most significant partner is Exxon Mobil), and A to Z. Both are impacted by the failure of social marketing to address both the needs of businesses (to make a profit) and society (to achieve a benefit), particularly in poorer countries.
A scandal two years ago, involving the U.S. Agency for International Development (USAID) - which spent 95% of its funding on consultants and only 5% on nets and insecticides - has further translated these paradigm failures into PR failures, making donors increasingly reluctant to support ITN programs.
The poor in African and Asian countries don't need Coca Cola, but their need for condoms is evident, as is their need for ITNs. Governments must resist the kind of corruption and favoritism that goes hand-in-hand with social welfare programs which benefit participating businesses more than people. And, while I'm all in favor of multinationals reaching out to the poor and unfortunate, I don't think it should be for the purpose of promoting their lineup of often unnecessary and frequently redundant products. True charity, says the Bible, is done without advertising.
"But when thou doest alms, let not thy left hand know what thy right hand doeth." Matthew 6:3, (King James Bible)