KEY POINTS:
Health researchers from the University of Otago, Christchurch, are working on a breath test for tuberculosis - with the aid of rats in Tanzania.
The large rodents have exceptionally powerful noses and have been trained to sniff out land mines in Africa.
Scientists from the university's Department of Pathology are about to visit Tanzania to check progress in studies there on diagnosing TB with the help of the Giant Gambian rat, a type of large African "sniffer" rat.
In a recent study, published in the international journal Tuberculosis, the researchers described the discovery of a number of what they called volatile bio-markers.
Such markers could be used to identify the disease much more quickly using a breath test, rather than current laboratory-based tests.
Here's where the rats come in.
After being taught to detect mines, the animals are now learning to detect tuberculosis bacteria in human saliva with the help of a grant from the World Bank.
The rodents can sniff 120-150 human saliva samples in lab dishes in 30 minutes compared with the day's work it takes for a human technician to analyse 20 samples.
The rats stop in front of samples that smell like TB and wait to be rewarded but walk past samples where TB is not present.
Said scientist Mona Syhre: "The rats are a robust real-life test of these potential bio-markers for TB."
Dr Syhre said her team wanted to find out if the rats did in fact sniff the bio-markers they had discovered.
She told NZPA today that if the rats verified her compounds as important for the diagnostics of TB in sputum samples, the next step would be to have a sensor company build a super sensitive and specific sensor - an electronic nose in other words - to detect the bio-markers.
"We can then try to detect these compounds in breath of TB patients on the spot. That is the long term goal."
Dr Syhre added the main difficulty was the extremely low quantity of the marker compounds.
The current lab process used to determine if someone has TB is still long and complicated.
Dr Syhre and infectious diseases specialist Professor Steve Chambers are basically trying to find a quicker, cheaper and simpler breath test.
"If [the work is] successful this will make a huge difference in speeding up diagnosis and treatment," Prof Chambers said.
The New Zealanders' work is supported by a $50,000 proof-of-concept grant from the university's commercial arm, Otago Innovation Limited, and the Health Research Council and Lotteries Health Research.
TB continues to kill more than two million people every year worldwide and is again becoming more prevalent in developed countries like New Zealand.
* Monday is World TB Day.
- NZPA
