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By Kayi Ntinda: Assistant Tutor, University of
Botswana.
Malaria! Malaria!
Africa!
Of late AIDS has attracted more concern and attention of
people than any other disease in the world, most particularly in the sub-Saharan
tropical Africa. The reason isn't far to see.
Potentially, it is the single most dangerous disease to ever
threaten the political,socio-economic structures and status quo of most
countries in Africa, not excluding Botswana. This is so because statistics
show that the most affected and infected sector of the population by the disease
are the youth. These are the most sexually active people in any population
and are aged between 18 and 49 years. Incidentally besides being sexually
active, they double as the most productive sector of any given economy.
They are ones in which governments; the private sector and families in general,
have invested so much in terms of money, education and training. One can
therefore understand the alarm, uproar and general concern attributed to this
disease, which is now not only an epidemic but pandemic. In countries such
as Botswana 35% of the population is HIV positive, the concern by the people and
government is very understandable.
Malaria, on the other hand, lurks as ever in Africa as it's
done for centuries. To date, it's the only disease that claims more lives
in sub-saharan Africa than AIDS. *** Every second in Africa 6 babies die of
malaria***Malaria doesn't pose as much threat as AIDS to the political and
social economies of African countries for the simple reason that although it
kills more people in sub-saharan Africa than AIDS, it's geographically confined
to only certain parts of Africa which are wet and hot. Malaria is mainly
caused by the mosquito parasite plasmodium ( usually falcipaarum). The
anopheline mosquito is the vector or carrier of the parasite. Its
elimination can practically end or wipe out Malaria from the face of the African
continent. The irony, however, is that despite technological advances made
in the medical field in general including the introduction of effective cure of
the disease by drugs such as quinine, chloroquine, nivaquine and the like, the
disease remains as potent and a threat as it was in the nineth centuries when it
devastated missionaries, explorers and the like who first came to Africa.
Although many people develop immunity from malaria, their
immunity is often not complete and they often lose it when they travel in and
out of affected parts of the continent. The disease is therefore recurrent
and science has failed to find permanent immune treatment for it. The good
news's that it's curable while AIDS isn’t, at least for now. ** the mosquito
kills more people in Africa than the lion**
As more attention is focused on AIDS, there is likelihood
that Malaria will receive less attention and therefore escalate. While
it's easy in theory to wipe out Malaria because the vector or carrier is an
insect, practically it's proved impossible.
Actually, AIDS is easier to control than Malaria as Uganda
and Senegal have already demonstrated. Infection rates there have
dramatically dropped. The reason is that the carriers of HIV are humans
and they can easily be educated. One hopes that technological means would
be available to '' educate the anopheline mosquito" Uganda's not stopped Malaria
for centuries. Why?
Education seems to me the effective tool of combating both
diseases. In the case of Malaria where populations are isolated and
geographically wide-spread and diverse the problem becomes real. It's
compounded by poverty and AIDS. HIV positive people are most likely to die of
AIDS when they have or develop malaria. That's why there's need for a
two-pronged attack.
Actually, in the final analysis the solution to both problems
lies in the elimination of ignorance and poverty. Poverty in Africa's the
single most threatening disease.
******* while there's no cure for AIDS yet, Uganda and
Senegal have managed to lower HIV infections but lamentably failed to lower or
eliminate deaths from Malaria!! And yet there's cure for Malaria! Is
it lack of political will?**********
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August 12, 2003 by Nicholas Wade: Source New
York Times. Posted by Ed Gragert.
Researchers racing to develop new
treatment for malaria, a disease now resurgent in Africa, have found a
peculiarity in the parasite's molecular machinery that may make it vulnerable to
the biological equivalent of a computer crash.
The parasite, a single-cell organism
known as a protozoan, goes through different phases in both its mosquito and
human hosts. Yet it has developed a very simple control system for governing at
least part of this complex cycle. It this system could be disrupted, the
parasite's thousands of genes would lose their tightly choreographed
coordination.
Last year biologists determined the
full sequence of DNA units in the microbe's genetic playbook. It has a
genome of 22.8 million units, coding for more than 5,400 genes. Two teams
of researchers, led by Dr. Joseph De Risi at the University of California at San
Francisco, and Dr. Elizabeth Winzeler of the Scripts Research Institution in San
Diego, have now made significant advances toward the next goal, that of finding
out what all these genes do. The teams have rival forms of expression chips,
devices that track what genes are active at a given time in the parasite's
life cycle.
The parasite spends the
proliferative phases of it's life cycle in the red cells of human blood,
feasting on hemoglobin and breaking out to infest further cells. The
successive rounds of infection cause the 48-hour cyclical fever of
malaria.
Dr. DeRisi' team cultured the
Plasmodium falciparum, the most deadly of the four forms of malaria, in vat
containing some five quarts of his own and other's' blood. In an article
being published online later this month in the Public Library of Science, a new
open access journal, lest in its blood-living stage, follows a just-in-time
inventory system. Each gene is switched on just before its product is
needed, Dr. DeRisi said. The genes turn on and off throughout the blood
infection cycle in a smooth cascade as regular as clockwork.
Most microbes have elaborate control
systems that engineer a response to every change in the environment. The
malaria parasite has been able to dispense with these complex controls, Dr.
DeRisi said, probably because it lives in the highly controlled environment of a
human blood cell. Less than 10 of the master regulatory genes known as
transcription factors have been detected in the malaria parasite's genome,
compared with the 141 reported in yeast and the thousand or so that control the
operations of a human cell. The simplicity of the parasite's control
system, Dr. DeRisi said, may open it to sabotage. "If you disrupt just one
of the regulatory program genes, you may disrupt hundreds of genes downstream
and cause the whole system to crash," he said.
The usual target of anti malaria
drugs until now have been the metabolic enzymes the parasite uses to digest
hemoglobin or synthesize building blocks of DNA. But the microbe can develop it
sidestep these one-target drugs. A drug that damaged it's control system,
however, might present a quite different problem.
Dr DeRisi's team tracked the
expression of the genes in the malaria parasite with a device of their own
design, a glass slide spotted with an array of short DNA segments that can
recognize and bind to every gene in the organism's genome. The technique
for building these DNA micro arrays, developed by Dr. DeRisi and Dr. Pat Brown
of Stanford University, has been made available to researchers. Dr
Winzeler's group used a commercial chip system, developed by Affy metrix, that
has a very different design but performed the same task, that of signaling when
a given gene is active in the parasite.
Thanks to Ed for
posting this to our www forum.
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