Africa Water, Sanitation & Hygiene Africa water, Sanitation May-June2015 Vol. 10 No.3 | Page 37

Water & Health

The research was conducted by CNRS, INSERM,
Université Paris Descartes at the Institut Cochin and the
Institut Pasteur in partnership with the London School of
Hygiene & Tropical Medicine.
Plasmodium falciparum has a complex developmental
cycle that is partially completed in humans and partially in
the mosquito. When in humans, the parasite inhabits red
blood cells (erythrocytes) in an asexual form.
These blood cells burst and some of the parasites continue
infecting and bursting more cells (causing the symptoms
of malaria), while others re-enter red blood cells to develop
in to male and female forms known as gametocytes. These
gametocytes deform the blood cell into a crescent shape
which slips undetected past the spleen’s blood filter. When
they mature they are then free to circulate in the blood and
can pass back to the mosquito when it bites an infected
human to take a blood meal.
Current treatments for malaria target the asexual forms of
the parasite which cause the symptoms of malaria, but have
little or no effect on the sexual forms that are responsible
for transmission to mosquitoes.
To tackle this problem, the researchers looked for a way
to change the shape of the deformed gametocyte-infected
blood cells so they were captured in the spleen. They found
that by using sildenafil citrate – better known as Viagra –
they were able to affect a molecular signal which stiffened
the shape of the parasite so that the rigid infected blood
cells would be detected and trapped in the spleen.
Study co-author David Baker, Professor of Malaria Parasite
Biology at the London School of Hygiene & Tropical
Me