Mycobacterium tuberculosis (TB) ranks as the leading cause of death from an infectious disease worldwide, alongside the human immunodeficiency virus (HIV). There are approximately 10 million new cases of TB per year and 1.4 million people died from TB in 2015. In many developing countries, TB is still detected through microscopy. Although this method can be very precise it's also slow and between 20-80% of positives can be missed, depending on the limited resources available and the skills of the technician. APOPO's detection rats technology is a fast, accurate and cost-effective screening tool to accelerate effective tuberculosis (TB) control. Constrained resources are a prevalent issue in regions that tend to have a high TB burden and APOPO relieves these countries of their dependence on the expensive and often unavailable TB diagnostics. The animals' resilience and versatility help to overcome the lack of resources as they are able to adapt and work in any environment under a vast array of conditions. By engaging scent detection technology to identify TB in human sputum samples, APOPO saves lives and enables people to stay productive and support their households, a highly important factor given the poverty levels in Mozambique and Tanzania. Moreover, the Detection Rats Technology empowers local communities to tackle dangerous, expensive and expert dependent detection tasks more independently, while creating local expertise to curb global humanitarian detection problems.
APOPO's tuberculosis detection rats are at least as accurate as conventional routine microscopy, but much faster. A tuberculosis detection rat screens a hundred samples in 20 minutes, this would take a lab technician four days. Thereby APOPO has managed to increase the TB case detection rate of the collaborating TB clinics by an average of 40%.
In order to know what exactly the rats smell, we still need to do a lot of basic research. But, our experience in the landmine detection and a PhD work by one of our staff suggests that the detection rats smell a bouquet of odor which is specific for Mycobacterium tuberculosis. This odor comprises of a specific blend of volatile organic compounds which the rats can recognize.
If samples are indicated by the rats we confirm their findings with concentrated smear microscopy. In Tanzania those positives are tracked by our partner MKUTA, which is a local NGO staffed by former TB-patients. TB treatment is provided for free by the government.
At the moment, the detection rats technology is not endorsed yet by the World Health Organization, and therefore National Tuberculosis Programs have not adapted our technology in their TB diagnostic guidelines. Currently, the rats are an excellent add-on test to sputum smear microscopy: at a relatively low cost we increase the case detection of new TB patients with over 40% in collaborating health clinics. Because of the speed and the low cost of the detection rats, this technology has great potential to be the initial screening test when actively screening populations at high risk of TB. We aim to evaluate the performance of the detection rats as a screening test in the near future.
In many developing countries, TB is still detected through microscopy. Although this method can be very precise, (when a sample is diagnosed as “TB positive” by microscopy, it is almost always a true positive) it can also be slow and between 20-80% of positives can be missed, depending on the limited resources available and the skills of the technician. Constrained resources are a prevalent issue in regions that tend to have a high TB burden. Every year, 9 million people globally are infected with tuberculosis (TB) yet about 3 million of those are missed and consequently don’t receive the care they need. Most of the 3 million missed cases of TB are in sub Saharan Africa because of inadequate health systems that are often unable to correctly diagnose TB in their clinics. Furthermore, the high HIV epidemic has aggravated the TB situation in this region, as diagnosing TB among HIV positive individuals is very difficult with microscopy. APOPO’s successful TB program is a step towards addressing the millions of TB cases that go undetected and can lead to death, in Africa and throughout the world.