Photo: Gary Hampton/World Lung Foundation
Innovative TB technology
JOHANNESBURG, 28 March 2011 (PlusNews) - In keeping with the focus on innovation as part of World Tuberculosis (TB) Day in March 2011, IRIN/PlusNews brings you a wrap of some of recent developments in TB technology.
1. GeneXpert: The two-hour TB test released in 2010 is a joint project by Cepheid, a diagnostic products manufacturer, the Foundation for Innovative New Diagnostics (FIND), a non-profit organization, and the University of Medicine and Dentistry of New Jersey, in the US.
The desktop computer-based system, approved by the World Health Organization, shaves three weeks off the usual waiting time for diagnoses and can test for TB and drug-resistant TB. Tests cost about US$20 each and are said to be more accurate than previous tests. The system was recently introduced in South Africa.
2. One-hour rapid test: The United Kingdom's Health Protection Agency (HPA) reported it had developed the test shortly after GeneXpert was announced. The one-hour test focuses on detecting a single DNA molecule in TB and expected to be more sensitive than most other rapid tests that look for a sequence of DNA, which may not be present in newer TB strains of TB.
HPA spokesperson Georgina Fletcher said the test did not yet have a name. Clinical trials are to start in the United Kingdom this year and it was too early to say what the cost per test would be.
3. TMC207: The only drug on our list represented a breakthrough in the treatment of TB as well as multidrug-resistant TB when successful trial results were published in the New England Journal of Medicine in the US in 2009. The as yet experimental drug does not need to be refrigerated, potential dosing could be as low as three times a week, and there are only mild side effects. Tibotec, the manufacturers of TMC207, started working with national regulatory authorities in March 2011 to determine the requirements for approval. Tibotec indicated that it might be able to provide some countries, such as South Africa, with accelerated access to the drug.
4. Signature Mapping TBDx: Created by the Aurum Institute, a South African health NGO, imaging specialists Guardian Technologies International, and South Africa's national health laboratory services, the TBDx diagnostic system takes digital pictures of sputum samples and searches them for TB's structural "fingerprint."
In much the same way that airport x-ray machines detect bombs, TBDx uses digital microscopes to detect TB microbes by their shape. After positive results from initial testing in the national health laboratory services, the system is now in the final stages of an independently controlled clinical study in South Africa. Results are expected in April 2011 and tests are expected to cost around $5 each.
5. The 30-minute, "bacteria counter" test: Researchers at Massachusetts General Hospital in Boston and Harvard University, both in the US, developed a half-kilogram hand-held device in 2009 that counts even low levels of TB in sputum samples, using small, iron particles and radio waves. The test is said to be as sensitive as those using TB cultures, which can take weeks to grow in a lab.
At the time of publication, IRIN/PlusNews had received no response to requests for information on whether or not the test had been evaluated in large-scale trials.
6. Computer-aided diagnostics: The Zambia AIDS Related Tuberculosis (ZAMBART) project has partnered with Delft Diagnostic Systems and University of Cape Town Lung Institute to install an easy-to-use digital chest x-ray machine in one of the busiest clinics in Lusaka, the Zambian capital.
Student radiologists take the x-rays, which are stored in an electronic database until a clinical officer can read them. The images in the database are being used to develop a computer-aided diagnostic programme that in the future could help diagnose TB without the help of a trained radiologist.