DDT - a necessary evil?
According to a WHO position paper on Indoor Residual Spraying (IRS), the practice has proven effective in the past at controlling malaria in many parts of the world. Only, somehow sub-saharan Africa was missed in these earlier efforts, and therefore, has a huge mosquito carrying malaria population.
IRS is the practice of spraying the pesticide on walls and roofs of houses and on animal shelters - places where mosquitoes may land in hopes of killing the dreaded vectors. The position paper advocates for the increased use of IRS with DDT. "DDT is the only insecticide which is used exclusively for public health, and, therefore, unlike with other insecticides, resistance development to it is no longer influenced by other uses such as in agriculture. In the context of resistance management, it is, therefore, advisable to maintain the use of DDT until a suitable alternative is available."
Enter those darned environmentalists again (the critics) getting in the way of saving the people of Africa. The WHO argument is that DDT garnered a bad rap (thanks in large part to Rachel Carson's Silent Spring) because of its widespread agricultural and "domestic hygiene" uses, which had drastic (and incredibly negative) effects on human, animal, and plant populations.
I blogged about this back in March, citing an article I had read in 2004 in The Ecologist about polio. The article makes a link between polio and the widespread usage of DDT, suggesting that the scientific history of polio is flawed and that pesticides may be to blame for polio, not a virus.
Of course this is just one article (and it is pretty damn convincing) - but it does make me wonder. Where are the strongest efforts of IRS, and where are the numbers of polio cases increasing?
In just an initial look through the WHO website at the polio eradication pages and the malaria eradication pages, Nigeria's explosion in polio cases seems to be attributed to a refusal by people to take the vaccination. And of the five countries listed in the position paper as being subject to "[t]he application of IRS consistently over time in large areas [that] has altered the
vector distribution and subsequently the epidemiological pattern of malaria," only two have been listed as priority polio countries, Botswana (2004) and Namibia (2006).
I don't disagree that malaria is an important disease that needs to be addressed, but is it an acceptable trade off to push to eradicate one disease at the risk of perpetuating another?