[MPWG] DDT use in global health initiatives

Fri Mar 21 11:31:12 CDT 2008

Transforming the malaria commodities market: the need for
interdisciplinary research and development of alternatives to synthetic
pesticide applications for disease vector control

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Jennifer Chesworth, founding director, Herbalists
Without Borders

info at herbalistswithoutborders.org

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Keywords: malaria, vector control, insecticidal
toxicity, DDT, biopesticides

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ABSTRACT

In recent years, global initiatives and multilateral
partnerships for prevention and treatment of malaria have taken great strides,
in reduction of malaria deaths, in garnering a strong funding base, and in
identifying regimes and products that are effective in disease vector
control.? In order for these regimes and
products to reach full coverage of malaria-vulnerable populations, global
initiative partners emphasize demand creation among consumers of malaria
commodities, along with subsidy and pricing structures that work for villagers
living in poverty while providing a reasonable profit margin for private sector
suppliers (1).? Effective social
marketing of approved technologies depends on wide acceptance and persistent
use of a variety of synthetic insecticidal treatments (1 through 6).? However, installation of new and emerging
markets for approved malaria commodities, while proven to reduce child deaths
from malaria (1, 2), creates new disparities between developed and developing
nations, since only a few, large multinational manufacturers are capable of
producing approved technologies (7). Meanwhile, concerns over potential
long-term health and environmental effects of insecticidal toxicity remain
largely unaddressed.? Funding is needed
for research and development of alternatives, such as biopesticidal
plant-derived essential oils, and for capacity-building that enables
village-level production of malaria commodities.? Supporting such initiatives may ultimately prove to be a greater
social good than building consumer demand for imported products that
potentially create new health and environmental risks.? 

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INTRODUCTION

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Roughly 3.2 billion people live in areas at risk of
malaria transmission.? At least one
million deaths from malaria occur annually, and malaria is the fourth cause of
death in children under the age of five. ?While some 60% of malaria cases and more than 80% of deaths from
malaria worldwide occur in sub-Saharan Africa (3), the geographic distribution
of the disease includes most tropical and subtropical regions, where factors
such as temperature, humidity, altitude, and rainfall are conducive to
proliferation of Anopheles mosquitoes and completion of extrinsic
incubation periods for malaria parasites.?
In cooler regions, transmission is less common and more seasonal.? The most malaria-vulnerable groups in high-transmission
areas are: young children, who have not yet developed immunity to malaria;
pregnant women, whose immunity is decreased during pregnancy; and travelers and
migrants from areas with little or no transmission, who lack immunity (3, 5).? 

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In poverty-stricken areas where economic development
and treatment options are limited, vector control, or prevention measures that
reduce contact with mosquitoes and kill adult mosquitoes and larval
populations, is the front-line defense against malaria.? Vector control measures identified as
priorities by global malaria initiative partners include insecticide-treated
bed nets (ITNs), indoor residual spraying, and source reduction (larval
control) largely depend on insecticidal applications.? Permethrin-treated nets and nets coated with longer-lasting
chemical insecticides (LLINs or long-lasting insecticidal nets); indoor
residual spraying using DDT and other potent contact insecticides; and a
variety of source reduction methods including insect growth regulators and
chemical insecticides applied directly to larval habitats, are currently
recommended and promoted by the World Health Organization (WHO), the Centers
for Disease Control and Prevention (CDC), and other global organizations
concerned with reduction and eradication of malaria (2, 4, 6).

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Malaria exacts a substantial social and economic toll
on both individuals and governments, including the financial, health, and
environmental burdens of insecticide applications and toxic waste disposal;
public health education and social marketing expenses; procurement,
distribution, and pesticide reapplications of ITNs and LLINs; costs of drug
treatments; maintenance of public health facilities; travel expenses to
hospitals and clinics; lost days of work and school; and loss of lives.? In light of these significant burdens,
debate over who should pay for commodities and services associated with malaria
treatment and vector control has focused on whether they should be considered a
public good, provided free of charge via the public sector with generous donor
assistance, or paid for by villagers with limited government subsidies, so as
not to decrease already low profit margins and thus, discourage participation
by the private sector (1, 2, 6, 7).?
Distribution of discount vouchers that separate the delivery of
subsidies and receipt of malaria commodities is encouraged to stimulate local
trade by building countrywide commercial outlets (1).? Production, demand forecasting, marketing, procurement, delivery,
and other supply chain operations are largely managed with heavy reliance on
international task force initiatives, dependent on existing regional health
services including immunization and antenatal care services, campaign-like
delivery of malaria commodities as part of relief efforts, and local and
national media campaigns.? Vector
control of malaria requires persistent outreach efforts and repeated
insecticidal applications.? To reach
global goals in malaria reduction using currently WHO-approved methods, it
further requires escalated and consistent donor assistance, and an
"enabling environment" for generating new local markets, through
"vigorous public and privately funded demand creation" (1).

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CHALLENGES IN CONVENTIONAL MALARIA VECTOR CONTROL

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Creation of demand among malaria commodity consumers
is problematic, since villagers living in poverty have little or no resources
even to purchase already-identified basic necessities.? This simple fact dramatically limits
participation by the private sector in international malaria prevention and
treatment initiatives.? According to the
Roll Back Malaria Partnership, additional factors that limit private sector
participation in the malaria commodities market include: inability to
accurately project scale of operations in light of uncertainty of future
demand; difficulty of meeting timing requirements of customers; costs of timely
production and delivery that lead to either decreased profit margins for
suppliers or increased costs for consumers; and uncompetitive bidding amongst a
small number of sizable players (7).?
Approved technologies for international vector control initiatives limit
who can participate in the market; anyone who might wish to participate must
have substantial available capital resources along with the technological
know-how for producing malaria commodities to required specifications.? The bottom line remains a profit margin that
is not high enough to attract more large multinational players.? This creates a monopoly of suppliers, one
which participating companies themselves find unacceptable (7).

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Another challenge that compromises the potential for
sustainability of approved vector control methods is insecticidal resistance.
Agricultural insecticide use may boost pests' resistance to health-related
insecticide applications, and vice versa. Resistance to every chemical class of
insecticides, including growth regulators and microbial drugs, has been
documented (8).? Because insecticidal
resistance is chaotic, determined by locally-specific variables that may be inconsistent
from one area to the next, and because disease vector mosquitoes may adapt
rapidly, having as many as 4 or more life cycles per year, the impacts of
insecticidal resistance on vector control and disease prevention is unknown
(8).? Along with careful monitoring and
evaluation of insecticidal resistance, global malaria partners and chemical
companies emphasize developing longer-lasting insecticide treatments for robust
polymer netting that combine pyrethroid and non-pyrethroid insecticides, as well
as production of a new generation of contact insecticides (1).? Development of genetically modified
mosquitoes that are refractory to malaria parasites is also underway (6).

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Along with difficulties in monitoring and addressing
insecticidal resistance, the human health effects of daily exposure over time
to insecticides in enclosed spaces, from treated bed nets and residual spraying
in homes and other buildings, as well as human and environmental health effects
of source reduction using insecticides applied directly to larval water
habitats and of waste disposal of old or damaged nets and empty insecticide
containers, may be poorly understood or overlooked in local and national
malaria vector control initiatives.? Point-
and non-point source contamination of water supplies from health-related
insecticide applications may be difficult to quantify or may elude water
resource managers' ability to differentiate between agricultural and
non-agricultural sources.? 

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Symptoms in humans of acute and chronic insecticidal
poisoning can be masked by symptoms of other diseases prevalent in
malaria-vulnerable communities, including malaria itself.? In high transmission areas where increased
incidence of malaria and intensified vector control measures are both present,
symptoms like vomiting and nausea, diarrhea, dizziness, headaches, malaise,
long term neurological impairment, and even infant deaths could potentially
result from either the disease or from insecticidal toxicity, or a combination
of both.? Children under five and
pregnant women, who are most vulnerable to malaria, are also most vulnerable to
the effects of systemic poisoning.?
Exposure in enclosed spaces to the least toxic insecticides used in
malaria vector control, the pyrethrins, still has documented health effects
which include dermatologic and ocular irritation, respiratory problems such as
coughing, dyspnea, pleuritic and upper respiratory pain, gastrointestinal
irritation, nausea and vomiting, headaches, dizziness, anxiety, tingling
sensations in the face and hands, and heart palpitations (9).? Where villagers are already weakened by
persistent health problems such as malnutrition, anemia, HIV/AIDS, and multiple
episodes of malaria, insecticidal toxicity from the combined use of
agricultural and disease vector control applications is potentially a high risk
to public health.? If, in light of the
need to control malaria, potential insecticidal toxicity in human beings is
deemed a reasonable risk for the time being, the long-term effects of
insecticides released in the environment, especially in areas with scarce
drinking water supplies, are unknown factors left for future generations to
address.

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TRANSFORMING THE MALARIA COMMODITIES MARKET: IS IT TOO
LATE?

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International malaria partnership members acknowledge
the need for equitable delivery of malaria commodities; that the approved
technologies themselves may be problematic is a sore subject of debate.? The fact is, current vector control methods
have successfully and dramatically reduced child deaths from malaria in
sub-Saharan African regions (1, 2).?
Requesting research and development of less toxic alternatives to
approved vector control technologies may be perceived as counterproductive,
taking the wind from the sails of global campaigns and compromising
relationships with current malaria initiative partners, many of which possess
formidable political power and financial resources. Governments of
malaria-endemic countries and charitable relief agencies risk alienating
themselves from existing donors and multilateral and private sector partners by
questioning the long term impacts of current malaria vector control initiatives
on public health, the environment, and on future generations.? Especially in light of aggressive campaigns
to create consumer demand, civil servants who speak out with concerns or
dissent risk going against the will of their own newly-educated people.

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While progress in the short term may cause the
concerns of organic advocates to fall on deaf ears, the future of
malaria-endemic regions is worth considering.?
Malaria has so far been eradicated only in temperate regions where
climatic conditions do not support year-round incubation periods of malaria
parasites.? In light of global warming,
those conditions may soon change.? Short
of causing the extinction of Anopheles mosquitoes and the parasites
responsible for malaria, do the great strides in reducing their populations
today guarantee sustained reduction of malaria vector insects and parasites in
the future?? For how long can large
donors support levels of giving for persistent and escalated purchase and
subsidy of malaria commodities and services??
If malaria commodities represent a new basic necessity for impoverished
villagers, how will steadily increasing indigent populations augment their
incomes to afford this rise in the cost of living?? With unprecedented shortages of water expected to worsen in the
all-too-near future, and given the difficulty and uncertainty of appropriate,
long term toxic waste disposal, where exactly will residual sprays and
long-lasting insecticidal treatments cycle through the environment before
ending up in what little drinking water there is?? Is it irresponsible to ask these questions, or to remain silent?

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CONCLUSION: THE NEED FOR RESEARCH AND DEVELOPMENT OF
ALTERNATIVES

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Given the dire need for sustainable economic
development in malaria-endemic nations around the world, the installation of
new and emerging markets for imported necessities, life-saving though they may
be, inadvertently broadens the economic divide between rich and poor and
creates new dependencies between developed and developing nations.? Capital and expertise for establishing
domestic commodity suppliers of approved technologies who can compete with
large multinational players is lacking in malaria-endemic nations (7).? Ultimately, creation of new high-demand
malaria commodities markets, whether production occurs within the borders of
endemic nations or not, comes with the social, environmental, and fiscal
burdens of toxic waste management and disposal.? The transfer of technologies to produce robust polymers and DDT
or other potent, long-lasting synthetic pesticides, while creating both point
source and non-point source toxic waste disposal issues, is not likely to
provide socially equitable employment and income for a broad sector of society
in malaria endemic nations.? Although a
large and generous body of donors has stepped forward to help end the suffering
in malaria endemic regions, sustainable and socially equitable economic development
that strengthens regional self-reliance and prudent local resource management
and protection are also needed to support viability and success of malaria
control and prevention in the long run.?

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Fair trade and organic product development in malaria
commodities markets is unlikely, though perhaps, not impossible.? For example, the African native
chrysanthemums used as source material for pyrethrum could be farmed
organically under fair trade cooperative management, and developed for vector
control use domestically, if intellectual property and patented technologies
allowing for effective product manufacture are equitably shared.? If a new generation of insecticides must be
developed, produced, and broadly adopted as a public good for malaria control,
biopesticides may provide effective solutions that more equitably support
sustainable regional economies and environmental protection.? 

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Botanical raw materials and plant-derived essential
oils known to be insecticidal via traditional knowledge and showing promise for
malaria vector control -- including lemongrass, eucalyptus, galangal, tea tree,
peppermint, thyme, oregano, rosemary, citrus species, citronella, rosewood,
geranium, and cinnamon, among others (10, 11) -- can be grown and processed by
agrarian villagers for their own local and regional malaria commodities
markets, if appropriate intellectual property rights are secured for villagers,
for the common good.? Though these
substances may be highly toxic in the concentrations needed for effective
disease vector control, requiring great care in handling along with educational
outreach in village settings to ensure safe application and waste disposal,
several traditional personal protection and fumigation methods have
complimentary medicinal properties (11) that may help counter persistent health
problems found in malaria endemic regions.?
Technologies for application and endurance of biopesticide mosaic
formulas, their effectiveness in malaria vector control, toxicity, agricultural
uses, complimentary medicinal benefits, and cost-effectiveness, have not been
adequately investigated and are likely to remain so until funding is allocated
by the international donor community.?
If global malaria initiatives aimed at high transmission areas are
deemed too important to halt in their tracks, at the least, village settings in
malaria-endemic regions of low transmission might be the testing grounds for
research and development of biopesticide alternatives in disease vector
control.?? These alternatives are worth
pursuing, if we wish to protect the environment and roll back poverty with the
same dedication we devote to our other worthy causes.

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REFERENCES

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(1)? World
Health Organization Global Malaria Programme (2007): Insecticide Treated Nets:
A WHO Position Statement, http://www.who.int/malaria/docs/itn/ITNspospaperfinal.pdf

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(2) World Health Organization (2005): WHO/UNICEF Joint
Statement: Protecting vulnerable groups in malaria-endemic areas in Africa
through accelerated deployment of insecticide-treated nets, http://www.who.int/malaria/rbm/Attachment/20050318/RBM-UNICEF-english3.pdf?? 

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(3) World Health Organization (2005): World Malaria
Report 2005, http://www.rbm.who.int/wmr2005/html/exsummary_en.htm? (accessed 2007-10-18)

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(4)? World
Health Organization (2007): WHO recommended insecticides for indoor residual
spraying against malaria vectors, http://www.who.int/malaria/cmc_upload/0/000/012/604/IRSInsecticides.htm? 

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(5) Centers for Disease Control and Prevention (2004):
The Impact of Malaria, a Leading Cause of Death Worldwide, http://www.cdc.gov/malaria/impact/index.htm? (accessed 2007-10-18)

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(6) Centers for Disease Control and Prevention (2006):
Vector Control,? http://www.cdc.gov/malaria/control_prevention/vector_control.htm? (accessed 2007-10-18)

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(7) Boston Consulting Group (2006): Roll Back Malaria
Partnership Procurement and Supply Management: Private Sector Diagnostic,? http://rbm.who.int/changeinitiative/PrivateSectorsNeeds.pdf? (accessed 2007-10-18)

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(8) Brogdon, W., and McAllister, J. (1998):
Insecticide Resistance and Vector Control. Emerging Infectious Diseases.
4:605-610.

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(9) Das, R., et. al. (1996): Pyrethroid Pesticide
Illnesses in Occupational Settings http://www.dhs.ca.gov/ohb/ohsep/pyrethro.pdf
(accessed 2007-10-18)

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(10) Tawatsin, A., Thavara, U., and Chompoosri, J.
(2002): Field Evaluation of Mosquito Coils Derived from Plants against
Night-Biting Mosquitoes in Thailand. Proceedings of the 3rd International
Conference on Biopesticides, Kuala Lumpur, Malaysia. 214-220.

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(11) Essential Science Publishing, 2004: Essential
Oils Desk Reference, 3rd ed. 

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