26 April 2005
This parasite officially kills a million people a year,
especially in
Monday,
April 25, was chosen as African Malaria Day 2005, an opportunity to highlight
the ravages caused by this infectious illness caused by a parasite - of which
four forms exist, the main one of which is Plasmodium falciparum - transmitted
to humans by the bite of certain mosquitoes. There are ways to prevent the
illness and effective treatments; however, about 40% of the world's population
is exposed to malaria. Between now and 2010, half the planet's inhabitants, or
close to 3.5 billion human beings, will be in that situation. Dr. Wenceslaus
Kilama, President of the International Malaria Foundation, provided a measure of
the number of victims of this epidemic: "Seven Boeing 747s full of
passengers that crash into
Unfortunately,
the appearance of forms of the parasite, the plasmodium, resistant to
chloroquine has progressively posed a major public health problem.
"Today," explains Jean-Marie Kindermans of Doctors Without Borders (DWB),
"we count four times as many cases and three times as many deaths from
malaria as during the 1970s." The levels of resistance to chloroquine are
as high as 70% to 80% of cases, in some regions of
A
new set combination of amodiaquine and artemisinine in a single tablet should
come out in 2006, thanks to the joint efforts of the DNDi Foundation, created by
DWB and the Pasteur Institute and the Sanofi-Aventis laboratory (April 11
edition of Le Monde). Several clinical trials published in the April 23 issue of
Lancet, as well as in the April edition of the online magazine Public
Library of Science (www.plosmedicine.org)
attest to the effectiveness of the ACT. The only hitch is that if "about
fifty African countries have decided to change their treatment protocol to
include the ACT drugs, today only nine of them have taken any concrete steps
towards this change," rails Jean-Marie Kindermans.
The
supply of artemisinine is a problem that has not been resolved, and in spite of
the warnings coming from DWB for the last year and a half about the interruption
in raw material supplies, nothing has happened, and the available supply remains
well below the demand. Along with the use of mosquito netting soaked in
insecticides, new paths to prevention appear promising. In The Lancet,
David Schellenberg's team demonstrates that a "preemptive intermittent
treatment," which consists of administering a dose of
sulfadoxine-pyrimethamine to a child three times during vaccination sessions (at
2, 3, and 9 months) allows a reduction in the incidence of malaria by 59% during
the first year of life and by 36 % in the course of the first two years.
"That
could constitute one of the most effective methods in the fight against
malaria," comments Jean-François Trape - on the condition that a
mobilization commensurate to the stakes involved occurs. Both a health and a
development problem, malaria represents a loss of 12 billion dollars a year to
Africa's Gross Domestic Product (GDP), while three billion dollars a year would
suffice to control this disease world wide.
No
Vaccination for At Least Ten Years
"Research
into an anti-malarial vaccine has progressed rapidly the last few years. (...)
However, it will most likely take a decade before an effective vaccination is
available for wide usage in the countries where malaria is endemic," deem
the Lancet columns of Professor Bernard Greenwood of the prestigious
London School of Hygiene and Tropical Medicine. The realization of such a
vaccine slams up against the complexity of the parasite involved. The latter
takes successive forms inside the human organism, each of which differs at the
immunological level: immunity to one of these forms confers no immunity to other
forms, and it has not been possible to experimentally provoke immunity against
the plasmodium before its passage into the blood stream. Moreover, the parasite
provokes disorders in the human immune system. Nonetheless, the completion of
the complete genetic sequencing of the Plasmodium falciparum genome, as well as
that of the mosquito which is the vector between it and humans, could offer an
opportunity for research based on biotechnologies.
www.lemonde.fr/web/article/0,1-0@2-3244,36-643123@51-643252,0.html
