Malaria and the Plasmodium parasite
Malaria
is an infection of the blood caused by the tiny protozoan Plasmodium
falciparum or Plasmodium vivax. The Plasmodium parasite is carried by certain species of mosquitoes
found in tropical regions across the world. The bite of the mosquito delivers the parasite into the
human blood stream, where the parasite grows first in the liver and then inside
the red blood cells. Soon the
infected person has a fever that comes in waves with joint pain, nausea, and
eventually may suffer organ failure and secondary brain infection that can be
fatal, particularly for small children.
Three hundred million people are infected and more than a million die
each year from malaria, most of them children in poor countries.
The parasite is becoming resistant to treatment
Malaria can be prevented or treated in a
number of ways. One of the best
methods is to avoid being bitten by mosquitoes that carry Plasmodium by using mosquito nets in combination with other
mosquito control methods. For
someone already infected, newer drugs are available, but in the countries where
malaria is prevalent, the medical system is challenged to deliver these new
treatments. The old treatments
with single drugs such as chloroquine have limited effectiveness because drug
resistant strains of Plasmodium
have now spread around the world.
Genomic technology and malaria
Genomic technologies developed by studying
simple organisms like BakerŐs yeast, the fruit fly, and the nematode worm, as
well as more complex organisms like mouse and humans are being applied more and
more to parasites that cause disease.
There are good reasons for this.
By learning all about the genes of the Plasmodium parasite we will learn new ways to foil its
growth. To help learn about the
genes of Plasmodium, many of
which are unknown or only poorly understood, students in the Ares lab have
adapted the UCSC genome browser technology to display information about Plasmodium genomes.
We are using the data in our "baby browser" to identify new genes and to make
better gene predictions.
Looking for new drugs against malaria
We are also about to begin screening small
molecules (chemicals) for their ability to inhibit growth of Plasmodium, in an effort to find new potential drugs. We collaborate with UCSC Professor
Scott Lokey on this project, which involves growing many tiny cultures of Plasmodium, each in the presence of a tiny droplet of a
different chemical. We have a
collection of more than 10,000 different chemicals to test, some of which may
kill the parasite. If we find such
chemicals, more testing will be needed to determine whether they are toxic to
human cells in culture, and then animals like mice or rats and then ultimately,
if successful, if they are tolerated by humans. It is a long road and many chemical candidates will fall by
the wayside. But we must look for
new treatment methods if we hope to slow or stop this parasite.
This project has been funded
by a grant from the Howard Hughes Medical Institute to develop new ways to
combine research and teaching in the undergraduate curriculum. Funding for this project is scheduled
to end in summer of 2006.