According to the World Health Organization, Tuberculosis is one of the top killers among infectious diseases: 1.5 million people died from TB in 2014. But many people who develop TB go undiagnosed, leading to millions of preventable deaths and allowing the disease to spread further each year.
The University of Washington is teaming up with the University of Cape Town’s South African Tuberculosis Vaccine Initiative (SATVI) for a long-term study of a new TB test, which would diagnose early-stage patients more easily and halt the spread of the disease. The project will be funded by a $1.02 million grant from the Bill and Melinda Gates Foundation.
Dr. Justin Shenje, a clinical researcher with the SATVI, explained that TB is a major public health concern in South Africa.
“In South Africa approximately 450,000 cases of active tuberculosis disease are diagnosed every year and this is responsible for 25,000 deaths annually,” he said. “This is despite availability of effective anti-TB drugs. Studies have shown cure rates above 90% when patients adhere to treatment.”
One hurdle to being treated is the current test that is used to diagnose TB. The test involves a patient going to a clinic and coughing up sputum, a sticky phlegm, which is then tested for the TB bacteria. But not all patients with the disease will produce sputum, particularly children, and even when it can be gathered, the test is not always effective.
Dr. Shenje added that sputum tests are also difficult to handle in a lab, and when patients attempt to cough it up there is a risk that they will infect healthcare workers. All of these factors prevent patients from being diagnosed, and allow the disease to spread further.
Instead of this complicated and risky test, UW researchers have developed a system that can diagnose TB through a simple swab of the patient’s mouth—think of the DNA tests done on crime shows, for example.
Dr. Gerard Cangelosi, a professor in the UW School of Public Health, is heading up the study. “Relative to sputum collection, oral swabbing is considerably easier for patients and clinicians alike,” he said.
Dr. Cangelosi’s team will work with Dr. Shenje and other researchers in Cape Town over the course of the two year study. They will test 245 South African adults and 100 children, some of whom are suspected of having TB, with both the swab and the sputum test.
“If oral swabs perform at least as well as sputum in terms of sensitivity and specificity, then we’ll be happy,” Dr. Cangelosi said. “If it performs better than sputum, we’ll be even more happy.”