Hello,
Harry, in my first email about this topic I specifically said that the
use of mosquito nets is very effective, yet is under employed because
such NGO's as UNICEF charge the recipients $5.00 US for each, making
them cost prohibitive to millions.
I have duplicated p.59-60 of the case studies from the IOMC report,
specifically on Sri Lanka's successes in malaria vector control because
of focusing on water management schemes. The first little bit summarizes
cost benefits pertaining to the Kheda, Gujarat district of India, where
bio-environmental management was found cheaper than DDT, and as
effective in terms of saving lives, without unnecessary harm to
environment and mammalian health.
Read the case studies. Occasional spraying is recommended in dire
circumstances, but it is stressed that it should be limited and other
avenues must be immediately initiated to avoid the trap of pesticide
dependence. Pesticide does not prevent recurrence, it merely stifles for
a short term what will come back with a vengeance. Root causes must be
addressed.
Being sensible and caring hardly means coming up with a better
insecticide. IPM/IVM is far more sensitive, caring and effective.
Returning totally to bio-dynamic methodology would be best.
Natalia
59
spraying (IRS) and under the innovative programme of intensified case
detection/
treatment and bio-environmental vector control (EMVC) were very similar
- about
two cases annually per 1000 persons. A cost-effectiveness analysis was
carried out in
1989, comparing the two programmes.
The per capita cost was Rs 5.5 in the IRS programme and Rs 4.5 in EMVC
programme.
The cost-effectiveness analysis took into account only the direct costs
of the
two programmes. Variables that could not be expressed in monetary terms,
such as
the environmental benefits of not using pesticides, were not included.
Additional
side benefits of the integrated programme, such as fish production, were
not included,
either. Including these benefits into the analysis would further enhance the
cost-effectiveness of the the integrated approach of case
detection/immediate treatment
and bio-environmental management for vector control.
4.2. Water management for
malaria control in Sri Lanka1
Sri Lanka is among six countries in the world,
outside of Africa South of the Sahara, which
share a third of the remaining global burden
due to malaria. The number of deaths is relatively
low, partly because of the quality of
health services and partly because P. vivax still
is the predominant parasite species, although
the trend is towards an increased share of
P. falciparum parasites. Transmission occurs in
the dry (<2000mm rain/year) and intermediate
zones (between 2000 and 2500 mm) with perennial transmission showing
seasonal
peaks linked to rainfall patterns. Great epidemics occur after droughts,
when the
southwest monsoon fails, because of the ecology of the local vector,
which breeds
profusely in rockpools remaining in dry rivers. The intensity of
transmission facilitates
conclusive studies on the effectiveness of different vector control options.
Malaria has been a serious public health problem in much of the
North-Central
Province of Sri Lanka for decades. A multi-disciplinary research team
with expertise
in vector biology and control, parasitology, health care, social
science, economics
and irrigation engineering (representing the International Water Management
Institute, the University of Peradeniya and the
Anti-Malaria Campaign of the Ministry of
Health) spent five years investigating the
malaria problem in the Huruluwewa watershed,
located within the North-Central Province.
The watershed has a 20 000 hectares catchment
area of mixed forest and agricultural land,
irrigated by an ancient tank-irrigation system,
which more recently has also been receiving
Water management
schemes based on
focused studies
lead to reductions
in vector incidence
1 Adapted from a contribution by Dr Felix P. Amerasinghe, Department of
Zoology, University of
Peradeniya, Sri Lanka; a useful up-to-date reference is Konradsen, F. et
al., 2000. Malaria in Sri Lanka:
current knowledge on transmission and contro l . International Water
Management Institute (IWMI),
Colombo, Sri Lanka
Case studies
60
Alternatives to POPs pesticides - a guidance document
water issued from the Mahaweli System. The Yan Oya stream is the feeder
canal to
the Huruluwewa watershed. The main malaria vector in this area is Anopheles
culicifacies. The main breeding habitats are the stream-bed pools that
remain when
water levels are low.
A significant risk determinant of malaria transmission is the distance
between
houses and the stream. At a system-wide level, villages closer than 500m
to the
stream had higher vector densities and a higher incidence of malaria.
The study
showed a relation between the stream water depth and vector breeding. When
water levels in the stream are low, more stream-bed pools form and once
the water
level is below 20 cm, the number of larvae increases significantly.
Detailed analyses
of the water dynamics of the entire watershed area followed. Models
showed that
with the current flow in the stream, water levels are low during two
periods of the year,
resulting in high densities of mosquito larvae. If the stream would be
flushed
regularly during these dry periods, breeding habitats of mosquitoes would be
disturbed, reducing larval densities. The most viable management option
was a
redistribution of existing water flows in order to maintain a water
depth sufficient to
discourage the breeding of the vector.
Cost analyses were done comparing the water management measures with vector
control interventions such as indoor residual spraying, mosquito nets
and chemical
larviciding, as well as with curative measures (hospitals, mobile
clinics, village-level
treatment centres) in the area. These showed that flushing streams
through seasonal
water releases from upstream reservoirs would be the most efficient
malaria control
measure.
Harry Pollard wrote:
Pete.
Natalia wrote about DDT being used directly on the
environment.
The WHO campaign sprayed the living quarters of people. As
DDT was fortunately persistent, only two sprayings a year
were needed.
Anyway, it worked with particularly spectacular results in
Sri Lanka where the existing hundreds of thusands of cases
dropped to fewer than 20 - until they stopped spraying.
Then, it surged into the hundreds of thousands again.
It wasn't stopped because of diminished ability to handle
the mosquitos - though that woud be inevitable.
However, if we had been sensible and caring we should have
been wotking on a replacement - DDX or DDY, or something.
But the environmental outcry turned scientists away from
the chemical.
Something I didn't put into paper was that a scientist in
PA followed up on the tests at Montrose Chemical plant that
found that DDT might be a) a fertility drug, and b) a
cancer inhibitor. His experiments seemed to confirm these
effects, but he stopped bothering with a dead end situation
and went on to other things.
Harry
**********************************
Henry George School of Social Science
of Los Angeles.
Box 655 Tujunga CA 91042
818 352-4141
**********************************
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:futurework-
[EMAIL PROTECTED] On Behalf Of pete
Sent: Sunday, May 27, 2007 6:40 PM
To: [EMAIL PROTECTED]
Subject: Re: [Futurework] Silent Spring is a case study
in the tragedy
of good intentions
On Sun, 27 May 2007, Harry Pollard
<[EMAIL PROTECTED]>
wrote:
How many will die until then?
Better resume spraying huts until the new ideas bear
fruit.
Harry
Simply spraying has the problems Natalia has noted,
unless it is
done intelligently. One very effective procedure is to
impregnate
mosquito nets with DDT. It selectively kills those bugs
which
have the tendency to seek out people, while not
compromising any
natural predators. There are probably lots of other
strategies.
As activists have noted, the problem is that as most of
the people
who suffer the infestations are poor, there is no
motivation for
big multinationals to expend any money on researching and
devising
solutions. In this regard, global warming may be a
blessing:
as climate warms, malaria may once again become a problem
for
wealthy societies. Then watch how fast new strategies
appear.
-Pete
**********************************
Henry George School of Social Science
of Los Angeles.
Box 655 Tujunga CA 91042
818 352-4141
**********************************
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:futurework-
[EMAIL PROTECTED] On Behalf Of pete
Sent: Friday, May 25, 2007 6:27 PM
To: [EMAIL PROTECTED]
Subject: Re: [Futurework] Silent Spring is a case study
in the tragedy
of good intentions
On Fri, 25 May 2007, Lawrence de Bivort
<[EMAIL PROTECTED]> wrote:
Does anyone know if malaria can be stopped by any
means
other
than
stopping DDT?
Currently, work is proceeding on identifying genes for
agents which
can identify and attack the blood flukes which cause
malaria. These
are not intended for use in human vaccines, though that
is also an
option. The grander plan is to develop either breed of
mosquito,
or a strain of gut bacterium which coexists in the
mosquito digestive
system, which is intolerant of the malarial flukes,
which
also
live in the mosquitoes gut. A malarial resistant
mosquito
is
also a stronger and healthier mosquito, which will
easily
outcompete
infected mosquitoes, and supplant them. It is
tentatively
estimated
such work may yield results in ten years, possibly
sooner.
-Pete
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