malaria in Africa

[Charlie Bell]

On 19/02/2008, at 3:44 AM, Dan M wrote:
>
> Which misleading comments were those?  IIRC, I was told by Charlie  
> that DDT
> was stopped because it lost its effectiveness.

In some areas, that is true, and DDT was replaced with pyrethroids.

"Resistance to DDT and dieldrin and concern over their environmental  
impact led to the introduction of other, more expensive insecticides."  
 From the WHO site.

>  The data from South Africa
> clearly showed that isn't true....

...in South Africa, where general spraying was not done to the extent  
that it was in India.

The article you linked to says this: "but the World Health  
Organization refuses to recommend DDT spraying." That's flat out wrong:

  "We must take a position based on the science and the data," said Dr  
Arata Kochi, Director of WHO’s Global Malaria Programme. “One of the  
best tools we have against malaria is indoor residual house spraying.  
Of the dozen insecticides WHO has approved as safe for house spraying,  
the most effective is DDT.”

That quote's from 2006.

 > Facts exist though,
>
>
> 1) Hundreds of thousands of people, if not millions, die each year  
> from
> Malaria

About a million.

>
>
> 2)  House spraying with DDT has a recent, multi-year record of  
> reducing
> these deaths _significantly_ in South Africa

True.
>
>
> 3) It is so much cheaper than other techniques.

Pyrethroid costs have dropped, and the cost difference is not as  
significant these days as it used to be (especially as some other  
chemicals can be used in lower dosage). But granted, it's among the  
cheapest methods.
>
>
> 4) There are multiple websites that attest to the EU's veiled threats
> against the use of DDT in Africa
>
> http://www.policynetwork.net/main/press_release.php?pr_id=92
> http://www.heartland.org/Article.cfm?artId=19127
>
> http://www.cbgnetwork.org/1180.html
>
> "While the EU fully acknowledges the urgent need to control malaria in
> Uganda, we are concerned about the impact the use of DDT might have  
> on the
> country's exports of food products to the EU," the European  
> Commission's
> Uganda delegation said last year.

Yes, they said that. And they're right to be concerned. Evidence must  
be produced that indoor spraying is being done in a controlled way,  
and constant monitoring must be done to ensure that levels of DDT do  
not increase in the wider environment.

Some other facts:

DDT is an irritant to insects, and increases their activity in the  
short term. DDT is not fast-acting, and this increased activity causes  
more bites in the short term from bed bugs (also disease vectors...).

DDT resistance in insects confers selective advantage *even when DDT  
is removed*, according to recent research ( http://www.scienceinafrica.co.za/2005/july/ddtinsects.htm 
  ). So DDT resistance will continue to spread, whether we use it or  
not.


> Let me ask a question I'm guessing you and Charlie find meaningless.

Why would I find it meaningless? Please tell me how that sentence is  
not incredibly patronising.
>  If
> millions are dying from malaria, and there is a cheap treatment that  
> has
> been proven, in the last few years, as well as in the past to cut  
> that death
> rate enormously....as the international funding to prevent that  
> disease
> doesn't pour most of the money into the most effective technique,  
> doesn't
> that indicate that there is something that is considered more  
> important than
> saving those people's lives?

The EU will, of course, do what it wishes right or wrong. Its up to  
people to make the right case, and with the WHO's backing for targeted  
indoor spraying including DDT where it is still efficacious, it's up  
in the air. There's private funding for spraying programs too.

As I have said, I support impregnated bed nets (and have done since I  
was convinced of their efficacy in 1992). I support very strictly  
monitored spraying indoors in the right dwelling types in areas where  
there is no resistance, and I have also said that before. But I  
continue to have reservations about DDT's long-term effectiveness, and  
the effects higher up the food chain are well documented, despite the  
recent media downplaying of it and the recent backlash against the DDT  
reclassification thanks to Silent Spring and Rachel Carson (who,  
incidentally, *SUPPORTED CONTROLLED INDOOR SPRAYING*).

But you're so busy banging on about it you can't even tell when people  
(well, me) agree with you, and what bits they agree with.

Charlie.