New diagnostic tests: Do not be surprised if a lab technician asks for a stool sample for a malarial tes

Syed Akbar
Hyderabad: Do not be surprised if a lab technician asks for
a stool sample for a malarial test. Researchers have now found that
the malarial parasite, Plasmodium, is capable of penetrating into the
digestive tract in human beings.

Earlier, the malarial parasite was found in the faeces of apes.
Research studies have now shown that human beings too shed this
parasite through the faeces. This makes the malarial test quite easier
if the patient is an infant. A sample of faecal matter can be tested
for the presence or otherwise of Plasmodium.

Though it has created a new avenue for Plasmodium testing, human
beings shedding the parasite through faeces may raise new challenges
for health experts and planners. According to a research report
released by the Centres for Disease Control and Prevention, United
States, scientists have found that similar to apes; infected humans
shed a detectable amount of Plasmodium falciparum in their feces. The
researchers have correlated the finding with results obtained by
special (polymerase chain reaction or PCR) tests. “Faeces are as
suitable as blood for malaria diagnostics for humans,” said Dr Milan
Jirku, one of the researchers.

“Our results show that in humans, P. falciparum efficiently penetrates
the faeces at levels detectable by PCR. Use of humans as proxies in
our study validates previous estimates of malaria infection rates
determined from faeces of great apes. The diagnostic method is
suitable in situations in which faeces are easier to obtain than blood
and for use with small children,” he pointed out.

A good correlation was observed between intensity of PCR products
obtained from blood and faeces, indicating that low parasitemia levels
result in poor amplification regardless of the biological material
used. In this dataset, the ability of blood and faeces to accurately
diagnose malaria was equal.