Health researchers from the University of Otago, Christchurch's Department of Pathology are investigating a unique breath test for tuberculosis (TB).

TB is still a serious disease worldwide, killing more than two million people every year, and is again getting a foothold in New Zealand because of household overcrowding and immigration from countries with high rates of the disease.

In a study, published in the international journal Tuberculosis, Dr Mona Syhre and infectious diseases specialist Professor Steven Chambers have identified a number of volatile TB biomarkers which could be used to diagnose TB much more quickly than current laboratory-based tests.

For the past century it has been a long process to confirm if someone actually has TB. It is still done by direct microscopic examination of sputum and then culturing of bacteria in the laboratory to confirm the initial diagnosis - a process which can take up to two months. PCR (polymerase chain reaction) testing has improved some aspects of diagnosis, but there are still many delays within the diagnostic process.

Syhre visited Tanzania earlier this year to carry out preliminary investigations into this new method. The scientists wanted to confirm if their TB biomarkers could be detected in real-life situations. This was achieved by using a type of large African "sniffer" rat, called Giant Gambian rats which are owned and trained by APOPO, a Belgian Humanitarian Organisation (

"Our visit to Tanzania was quite successful as we showed that the rats are able to identify which samples had been spiked with TB biomarkers," says Syhre. "This was the first time our results were tested outside the lab and it means we can go onto the next stage of the investigations."

African "sniffer" rats were able to identify TB biomarkers.

This will entail visiting another developing country where there are many TB patients, and testing breath and sputum samples for the presence of the biomarkers using a special GC/MS machine. Syhre says using "sniffer" rats is not practical long-term in relation to developing a simpler TB test, and the lab tests will provide more confirmation.

The encouraging results so far are supported by a $50,000 Proof of Concept grant from the University of Otago's commercialisation arm, Otago Innovation Limited. The aim of the grant is to encourage researchers to think about possible commercial applications of research, including the end product and its potential market.