infected with malaria produce a distinctive breath or a "breathprint" that has
allowed a new study to develop a novel breath test to identify infected
individuals and diagnose malarial infection.
- People infected with malaria
exhale a distinct "breathprint" that was used by a research team to
develop a diagnostic test for malaria.
- The test identifies a set of 6
compounds in the human breath that can serve to identify malaria.
- The study also found that terpenes
released by infected humans are similar to a plant-produced molecule that
attracts mosquitoes, carriers of malarial parasites.
The diagnostic test was a success in diagnosing malaria in a group of
African children, says the study that was presented at the American Society of
Tropical Medicine and Hygiene (ASTMH) Annual Meeting.
For the first
time the study was able to identify a set of compounds in the human breath
that could serve as markers to diagnose malarial
infection. This study is also the first to discover that
infected people have a distinct breath, they call the "breathprint."
like the DNA blueprint inside of us gives information on the genetic level, the
breathprint gives information on whether the person is affected with malaria or
team identified malaria as the target for breath-based analysis as previous
studies showed that the malarial parasites were capable of altering compounds
that humans exhale.
from Africa aged 3 to 15 were recruited out of whom 17 were previously tested
positive for malaria and 18 tested negative. The objective of the study was to
check if the breath test they developed could correctly identify the infection
status of these previously tested children.
‘People who are infected with the malarial parasite release a compound called terpenes which is the same compound produced by certain plants to attract mosquitoes.’
The children were asked to blow into a
balloon like bag that contained an absorbent material to trap the vapor. This
was further sent into the laboratory in Washington University in St. Louis for
analysis. Here it was discovered that malarial infections altered
concentrations of 6 different compounds that naturally occur in human breath.
concentration measure was used to distinguish infected and uninfected breath
samples. The test was accurately able to determine the malarial infection
status in 83% of the children that gave the samples.
"We were able to determine whether the children were infected
or not based on the composition of six different compounds that were detectable
in a sample of their breath," said Chad Schaber, who presented the results
of the study, produced by a team of biologists and bioengineers from Washington
University in St. Louis. "We took breath samples from 35 children and we
correctly determined the malaria status--whether they had malaria or not--for
29 of them, which is an 83 percent success rate."
Problem with current
diagnostics for malaria
While there are
several diagnostic tests for malaria including the rapid diagnostic tests
(RDTs) which are finger prick tests, these continue to provide positive results
even when the infection has subsided. Moreover, the deadliest malarial
parasite, Plasmodium falciparum, does not produce the protein that
most of these tests
rely on, making the malarial parasite undetectable.
Future prospects for
breath-based malaria detection
The research team hopes to improve the
diagnostic method by combining it with the latest technology. They hope to develop
electronic noses or eNose which are pocket size devices that can be designed to
detect specific smells.
There is already a prototype eNose that is under
development to diagnose tuberculosis
with a breath sample.
Spread of malaria through
When the breath samples of children
were analyzed, the research team discovered two types of compounds called
. One of these terpene compounds was identified to be the same as
the one produced by certain plants to attract mosquitoes to feed on nectar.
"The terpene is probably a
survival mechanism for the parasite, but this compound also might be useful in
boosting the effectiveness of mosquito traps used in malaria control
efforts," said Audrey Odom John, principal author of the study and
associate professor of Pediatrics and of Molecular Microbiology at Washington
University School of Medicine.
The research team believes that the
malarial parasite is "hijacking" the mosquito's in built attraction to odor.
This encourages mosquitoes to bite infected people who release mosquito
attracting compounds in their breath.
"The malaria parasite has been
outwitting human interventions for thousands of years, which is why we need
these innovative collaborations between biologists and engineers to develop new
tools that can give us the upper hand," said Patricia F. Walker, MD,
DTM&H, FASTMH, and President of the American Society of Tropical Medicine
and Hygiene. "It sounds almost like something from science-fiction, but
the ability to detect disease with a breath test may be closer than we ever
could have imagined or hoped for."