LONDON (Reuters)
- Researchers have discovered just how the malaria parasite feasts
on human blood cells in a breakthrough that could lead to new
treatments for the world"s most dangerous tropical disease. Malaria
kills more than a million people each year and researchers now
have a new understanding about how the parasite survives and grows
in its human host.
The scientists
found that up to 2,000 pore-like holes on the membranes of infected
red blood cells provide the nutrients needed for the hungry mosquito-borne
parasite, plasmodium flaciparum. Scientists at the U.S. National
Institutes of Health said the discovery of the so-called feeding
channels could lead to a new approach to combat the disease. "It
has been known for some 25 years that the parasites increase uptake
of certain nutrients but the mechanism was not known," Dr Sanjay
Desai said in a telephone interview. "With this information, researches
may be better able to develop drugs to cut off the parasite"s
nutrient supply."
The malaria
expert at the Laboratory of Parasitic Diseases at the National
Institute of Allergy and Infectious Disease (NIAID) in Bethesda,
Maryland, used a technique called electrophysiology to find and
study the channels, only present on infected red blood cells.
The holes are made by specialised proteins that allow just the
right nutrients for the parasite to come through. Scientists are
not sure if the parasite changes a protein in the cell membrane
to create the channel or if it brings in a new protein and incorporates
it into the cell membrane. If a new protein is added to the cell
surface it could be a good target for drugs designed to block
the feeding channels and starve the parasite to death.
IMPORTANT
STEP IN UNDERSTANDING MALARIA
Dr Anthony
Fauci, director of the NIAID, described the research in the science
journal Nature as a major achievement. "This discovery is an important
step forward in our understanding of malaria and the search for
new interventions to reduce the burden of this devastating disease,"
he said in a statement. Malaria is the most prevalent tropical
disease in the world with 300 to 500 million people being infected
each year. More than 40 percent of the world"s population live
in countries where malaria is endemic.
Ninety percent
of deaths from the illness occur in Africa. Two-thirds of deaths
are among children. Although drugs have been available for decades
to fight the disease, climate change, social instability, increased
travel and resistance to pesticides and drugs have increased the
death toll. The disease causes high fever, muscle stiffness and
sweating. Cerebral malaria, the most dreaded form, results in
death within 24 hours. In addition to malaria, Desai said the
research, a collaboration with scientists from The National Institute
of Child Health and Development in Bethesda, Maryland, could also
have implications for other parasitic diseases. "There is some
evidence that other related parasites use similar mechanisms,"
he said.
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