Malaria- DDT is NOT the answer
Changing gear a bit here…been a while since I blogged…now looking a the way DDT is being pushed down Afrika’s throat…fuuucking hell…when will the insanity end!
DDT is NOT the ANSWER!
The enthusiasm with which DDT use is being touted as a ‘solution to end malaria’ in Africa is sickening. Oh kind-hearted people of the world (the mantra goes), ‘Help save African babies as you are helping to save the environment.” (Oh altruism, I thought you were lost, but alas DDT has brought you back…riiiggggght.) But what is completely flabbergasting is that many Africans are NOT concertedly challenging this mantra. Most people seem to be smiling and nodding…yes yes…we need this DDT to get rid of malaria. Oh yeah? At what cost?
Let’s just deal with this by looking at what those advocating DDT are saying, and then look at what they are NOT saying…you decide which arguments convince you more.
Pro DDT arguments:
1) Where DDT is used, malaria deaths plummet. Where it is not used, they skyrocket. For example, in South Africa, the most developed nation in Africa, the incidence of malaria had been kept very low (below 10,00
0 cases annually) by the careful use of DDT. When small amounts are sprayed on interior walls, DDT forms a residue that both repels mosquitoes — discouraging them from flying into the house — and kills those that rest on the walls.
2) No other chemical comes close to
DDT as an affordable, effective way to repel mosquitoes from homes, exterminate any that land on walls, and disorient any that are not killed or repelled, largely eliminating their urge to bite in homes that are treated once or twice a year with tiny amounts of this miracle insecticide. For impoverished countries, many of which are struggling to rebuild economies wracked by decades of disease and civil war, cost and effectiveness are critical considerations.
3) DDT is a pesticide used to control insects that carry diseases such as malaria. Numerous studies indicate that DDT is not a carcinogenic hazard to humans. However, EPA lists DDT as a ‘probable human carcinogen.’ Studies conclude that there are no serious effects in people under normal use. According to ATSDR, there are no studies on the health effects of children exposed to DDT. There is no evidence that DDT causes birth defects in people.
The counter-arguments to these points are what is NOT being said. So let me do that, point to point.
1) DDT use does not end malaria- especially in tropical climates?
The World Health Organisation (WHO) has tried this before in its War on malaria in the1960s. It failed- for countries with tropical climates. For example, in Sri Lanka (which was cited as one of the successes of the project) they used DDT spraying as a technique to control malaria and it failed due to a number of factors the most important on being that, ‘Apart from operational and administrative shortcomings, the main reason for this second increase was the development of vector resistance to DDT, to such an extent that it was necessary to change to the more expensive malathion in 1977.’
This leads us to the next problem with the DDT spraying argument. Its really hard to pull it off, ‘For effective control of mosquitoes, at least 80 per cent of all households must be covered every 6-12 months by well-coordinated spray teams. Is this possible in Africa? Imagine trying that across the Congo basin! It is not realistic to assume that this will happen. It will just leave the communities vulnerable again.’
In the cases where DDT has DDT has been used effectively namely, South Africa, parts of Europe and the USA, they have TEMEPRATE climates so their weather is already waging half the battle against the mosquitoes. The survival of mosquitoes that carry the malaria parasite (yes not ALL mosquitoes are malaria vectors) is dependent on three things: temperature, precipitation and humidity. By the far the factor on which most work has been done and which is very clearly affect the survival of malaria and the mosquitoes is temperature.
The minimum temperatures for parasite development are between 14-19°C. The optimum temperature for mosquitoes is 25-27°C. Below 20°C, the life cycle of P. falciparum (the malaria parasite strain that is most dangerous and most difficult to treat) is limited. ‘ 
Most Sub-Saharan African temperatures range between 20°C- 27°C ALL YEAR round. So our temperature is always perfect if not optimal for malaria and mosquito reproduction We ar called malarious zones). S. Africa is at the tip and is therefore temperate, in fact a study on South Africa-malaria-temperature interaction showed that,’ (H)igher than average mean September temperatures were associated with an increase in the severity of malaria in the following year.’
The reason why tropical climates get Since we have a TROPICAL climate where residues of the parasite and mosquitoes ALWAYS linger, DDT use in Africa for purposes of malaria control will have to me much more intense and concentrated than in those other areas of the world.
Another point to note on why South Africa go rid of malaria so easily is because, its NOT a malarious Zone. Malaria comes in seasons in South Africa. In African countries where the burden of malaria is greatest, the disease is endemic. Uganda (and other African countries with a high malaria burden), where it rains throughout the year, could not be more different from South Africa in terms of malaria, and it is a mistake to apply the same formula here. The use of DDT for indoor residual spraying will not produce the same results and will almost certainly have dire consequences. 
2) Will using DDT really be cheaper for Africa?
There is no evidence that this is the case, ‘Malaria control decision makers who use or want to use DDT to combat malaria say they want to use it because it is both effective and inexpensive, when compared to alternatives… However, none of the malaria control or insecticide control specialists in Ethiopia, Uganda, Kenya or South Africa could cite a formal cost-effectiveness study to assess whether using DDT was, in truth, the most effective and inexpensive method to be used. …” 
Even if DDT were more cost effective and even if it were going to produce the so-called MAGICAL effects and exterminate mosquito populations the truth is that , ‘Each time scientists find a way to fight the parasite (malaria), the parasite finds a way to fight back. It has become resistant to most treatments, for example. And some mosquitoes have already adapted to tolerate DDT.’  Also, DDT won’t work in some places where mosquitoes already are resistant to a range of insecticides. 
So what we’re doing is putting Africans at risk, well aware of the fact that this parasite will probably become resistant to this supposedly fool proof chemical…so in 10 or so years not only will Africa be reeling from the effects of DDT (see below) we will also be living with killer- strong parasites and mosquitoes resistant to DDT.
We therefore would have spend money on doing the DDT operations in our country, then be hit again as Africans continue to die against a parasite that is even stronger. But by then the North (since the Northern institutions are the ones that are always ‘inspired’ to THINK on Africa’s behalf and find solutions for us) would have come up with another brilliant idea to end malaria forever-for real this time. Brilliant plan!
3) What are the effects of DDT?
Right now we are being told, in very rational and scientific language, that DDT is not a problem and that, ‘Regarding the possible dangers of DDT to humans, studies of (DDT) spray-men in India and Brazil and workers in DDT factories in the U.S.A. showed elevated levels of DDT in serum or body fat, but medical follow-up showed that this did not appear to have done them any harm.’ 
Statements such are these are dangerous and misleading because there IS evidence that DDT is harmful. For those interested in looking at the environmental effects look here (scroll down http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/ddt-ext.html) and here (http://www.eco-usa.net/toxics/ddt.shtml ) . (Mind you, while reading the link I think we should keep in mind that humans ARE A PART OF THE ENVIRONMENT. It’s hilarious how science encourages us to distinguish the effects of chemicals into ‘human’ and ‘environment’ effects. Yeaaaahhh ooo-k. If we let toxins accumulate in the environment and adversely affect the ecosystem, of COURSE we’ll be adversely affected as well….no rocket science required to understand that- I hope. Anyway in this part we will focus on the effects on humans.
Effect on humans
DDT is an organochlorine that persists in the environment long after use, accumulating in the food chain and in fatty tissues of animals and humans.
On the mental functioning in children
A study published in The American Journal of Epidemiology found that the higher the concentration of DDT to the child in pregnancy to lower the child’s verbal, memory, quantitative, and perceptual-performance skills at age 4 years. It indicated that pre natal exposure to background, low-level concentrations of DDT was associated with a decrease in preschoolers’ cognitive skills.  Add to this the fact that DDT is concentrated in breast milk because it is lipophilic and the secretion of stored DDT into milk is the main route for excretion of DDT in lactating women.
On reproductive health
A study done by the Centre for Research on Women’s and Children’s Health at the Berkeley Public Health Institute found that, ‘(T)he higher the concentrations of DDT in their mother’s blood, the longer it took the daughters to become pregnant. The daughters’ probability of becoming pregnant fell by 32% for each 10 microgrammes of DDT per litre of blood.’ 
Research done by scientists at the National Institute of Environmental Health Sciences, the National Institute of Child Health and Human Development, the University of North Carolina and the Centres for Disease Control and Prevention shows that, ‘DDT increases the risk of pregnant women having their babies before 37 weeks of gestation…DDT use increases pre-term birth, which is a major contributor to infant mortality.’
A chemical derivative of DDT (DDE)·, mimics the effects of the oestrogen hormone, which plays an important role in controlling sexual development. A three year study in the US, 20 years ago, found that the children of pregnant mothers whose blood and breast milk contained high levels of DDT, reached sexual maturity earlier.
The US Department of Health and Human Services (DHHS) has determined that ‘DDT may reasonably be anticipated to be a human carcinogen’. Work carried out by the US National Cancer Institute correlates breast cancer in women with increased levels of DDE in blood serum. From 14,290 women monitored in the New York University Women’s Health Study, researchers selected 58 women who had developed breast cancer and 171 matched controls without cancer. After adjusting for participants’ childbearing and breast feeding histories, and for family history of breast cancer, researchers found a four-fold increase in relative risk of breast cancer for women with elevated levels of DDE in the blood.
On the nervous system
Acute effects likely in humans due to low to moderate exposure may include nausea, diarrhea, increased liver enzyme activity, irritation (of the eyes, nose or throat), disturbed gait, malaise and excitability; at higher doses, tremors and convulsions are possible.
In humans, blood cell cultures of men occupationally exposed to DDT showed an increase in chromosomal damage. In a separate study, significant increases in chromosomal damage were reported in workers who had direct and indirect occupational exposure to DDT. Thus it appears that DDT may have the potential to cause genotoxic effects (toxic effects to genes) in humans, but does not appear to be strongly mutagenic (cause mutations).
The way forward
There are other options to DDT that are effective and safer, ‘Deltamethrin and cyfluthrin were found to be much superior to DDT, HCH or malathion in vector control in trials in India.’Can we PLEASE look into these other options before jumping on the DDT band wagon.
DDT is not the magic bullet that will eradicate malaria. We need to refocus resources and attention on something most Africans do not have: basic malaria education, and prevention with insecticide-treated bed nets while at the same time spending as much effort exploring other compounds that can be used for indoor-spraying.
If we are going to use DDT, then we MUST use it as PART of a larger malaria plan and NOT tout it as the answer to malaria. We must also KNOW that we may be putting ourselves in harms way in the process.
· Note: DDT is degraded DDE and DDD when metabolised