Researchers at the University of Washington School of Public Health helped develop a protocol to test for TB in easy-to-obtain oral swab samples, greatly improving upon existing detection methods.

"One of the main limitations with diagnosing TB is that you have to analyze a sputum sample," said Gerard Cangelosi, professor of environmental and occupational health sciences at Washington and corresponding author on a paper in Scientific Reports that details the new detection method. He collaborated with other UW scientists as well as researchers at the South African Tuberculosis Vaccine Initiative and the University of Cape Town, South Africa.

Working with sputum samples is challenging due to the material's highly viscous nature, scientists say. Sputum can hide pathogens from pathologists because it is difficult to dislodge bacteria from within the mucus' milieu. Patients must also cough to produce a sample, putting public health workers at risk for contracting the disease.

Determined to develop a better approach, the researchers found inspiration in veterinary medicine, where technicians test for pathogens in oral swab samples. Lisa Jones-Engel, a research scientist in the UW National Primate Research Center, advised the study team in applying the method to human disease.

Scientists swabbed the mouths of 20 TB patients as well as 20 healthy individuals. Samples from patients with confirmed TB were taken in a clinic in South Africa. Control samples were taken from healthy individuals living in Washington state.

Rachel Wood (MS, Environmental Health '14) and other researchers detected TB in oral swabs taken from 18 of the 20 confirmed patients. None of the samples from healthy volunteers tested positive.

Cangelosi says "an oral swab is a very simple, non-invasive sample to take" and that the use of oral swabs "could be a real game changer for TB control because it could make diagnosis cheaper and easier." TB claimed the lives of about 1.5 million people in 2013, according to the World Health Organization.