Plasmodium falciparum, a causative
agent of Malaria :
Malaria is caused by one of four species
of Plasmodium (falciparum, vivax,
malariae and ovale). Of these P. falciparum
is the most lethal being estimated
to cause 200 million clinical cases,
and 1-3 million deaths (including
many children) every year world-wide. There
are approximately half a billion new
cases of Malaria every year. The genome
sequence of Plasmodium falciparum
was published in Nature Magazine in
October of 2002.
The parasite has a complex life cycle
and is transmitted to humans by the
female anopheles mosquito and goes
through the life cycle shown in the
two figures below.
Courtesy of
http://post.queensu.ca/~forsdyke/images/pfalcip04.gif
Detection
of Plasmodium falciparum:
In many
endemic countries, the diagnosis
of malaria is made on the basis
of clinical symptoms. However,
the diagnosis of malaria is
complex because the symptoms
overlap with other diseases
endemic to the same regions
known to have malaria endemics. This
often results in treatment with
anti malarial drugs of patients
that do not have malaria and
others that have malaria are
misdiagnosed and left untreated. The
emergence of drug resistance
is a common problem in african
countries due to poor diagnostic
methods.
Peripheral
smear microscopy remains the
"gold standard" for the diagnosis
of malaria and it should be
used whenever possible. However,
it is hard to maintain the standards
required for good microscopy. Thick
malarial smears require skilled
technologists to evaluate the
slides. Another reliable method
for detection that may be a
little more costly is the detection
of parasite HRP2 protein or
plasmodium lactate dehydrogenase,
released by the infected red
cells.
Detection of Plasmodium falciparum
DNA by Polymerase Chain Reaction
is a highly sensitive approach
to diagnosing the disease in
a short time. Because
of the high specificity and
sensitivity of the test, it
is being used more commonly
especially in countries that
do not have the malaria endemics.
Sample
required
Turnaround
Fresh
whole blood collected in EDTA
tube and shipped cooled overnight.
