Malaria Breath Test Shows Promise


(Partly adapted from Michelle Roberts – BBC Health)

By  Victor Mwila

Researchers from Washington University in the United States have started trying out a new and exciting malaria diagnostic test that uses breath odours. They have already tried out a crude prototype breathalyser in Africa. The test was reasonably good at detecting cases in children, but needs developing to become a routine device. Although the test needs perfecting, it could offer a new cheap and easy way to help diagnose malaria, the researchers say.

The researchers state that a person with malaria gives off distinct breath odours, and one of the odours given out is identical to a natural smell that attracts insects that spread malaria. Pine trees and conifers emit chemicals called terpenes to summon mosquitoes and other pollinating insects, say the researchers. They believe people with malaria who have this odour in their breath may also attract mosquitoes and infect insects that bite them. The infected insects can then spread the disease to other people they bite. The prototype breath test detects six different odours or volatile organic compounds to detect cases of malaria.

The researchers tried it on breath samples from 35 children in Malawi who had fever, some with malaria and some
without. The results were impressive; the test gave an accurate result in 29 of the children, meaning it had a success rate of 83%. However, this is still too low for the test to be used routinely, and the researchers hope they can improve its reliability and develop it into an off-the-shelf product. Simple, rapid blood tests for malaria are already available, but they have limits. Testing blood can be expensive and technically challenging in rural areas. So a non-invasive method of detection that does not require blood samples or technical expertise could be of great benefit.

Prof James Logan from the London School of Hygiene and Tropical Medicine said: “The rapid detection of asymptomatic malaria is a challenge for malaria control and will be essential as we move towards achieving the goal of malaria elimination. A new diagnostic tool, based on the detection of volatile chemicals associated with malaria infection is exciting.” He said more work was now needed to see if it could be made into a reliable test. The findings are being presented at this year’s annual meeting of the American Society of Tropical Medicine and Hygiene.