Country of Operation
Target income level
- Bottom 20%
- Lower-middle income (20-40%)
- Middle-income (40-60%)
- Higher middle-income (60-80%)
- High-income (80-100%)
SummaryAPOPO is a social enterprise that researches, develops, and deploys detection rat technology for humanitarian purposes. APOPO's HeroRATs provide second-line screening of TB samples from collaborating DOTS Centers.
Tuberculosis (TB) is a widespread disease. 1.7 million people die from TB each year. Only 50% of the patients with TB are diagnosed. Left untreated, a person with active TB can infect 10-15 new people each year. A faster, more accurate diagnostic technology is needed to help curb the spread of this deadly disease.
To address this need, APOPO developed a unique diagnostic technology reliant on the olfactory capacity of trained giant African Pouched rats. APOPO uses operant conditioning to train the rats to detect TB from human sputum samples. Briefly, the rats are taught to indicate samples that contain TB bacilli and not to indicate those not containing TB bacilli. APOPO aims to expand implementation of this technology.
Key program components
Trained HeroRATs can quickly and accurately sniff out TB in human sputum samples. Trained rats can evaluate 40 sputum samples in just seven minutes, equal to what a skilled lab technician will do in a full day’s work.
In Tanzania, APOPO’s trained TB detection rats are used as a second-line screening to TB clinics. APOPO collects samples that have been evaluated by technicians at the clinics and processes them for a second evaluation by the rats. Rat indications over samples found positive by the TB clinics are rewarded with food. The samples found negative at the TB clinics are considered suspect for TB. Rat indications on these samples are not rewarded, but a smear is prepared from those samples and checked by FM microscopy in APOPO’s laboratory. APOPO’s technicians then send back to the TB clinics a list of new patients confirmed by microscopy. In this second-line screening capacity, APOPO has increased the detection rate of the collaborating TB clinics by 30%. To-date, the rats have detected more than 3,800 TB patients that were missed by conventional microscopy, thereby preventing tens of thousands of potential infections.
Similar operation was launched in Maputo, Mozambique in January 2013. As of July 2013, 273 TB patients were detected by APOPO’s TB detecting rats that were already missed by the conventional methods in the eight collaborating TB centers.
In 2011, the rats’ diagnostic capabilities were scientifically evaluated relative to culture, the current “gold standard” diagnostic tool. In this study, Dar es Salaam technicians found 48% of culture-positive patients while a single rat, on average, found 67%. When used as a group of four, the rats’ patient detection increased to 78%.
One of the WHO requirements for a new TB diagnostics registration is its cost-effectiveness documentation. Cost-effectiveness analysis is usually done against a certain reference such as routine microscopy. However, rigorous analysis may require employing different reference methods such as GeneXpert, LED microscopy, and culture. APOPO recently launched this study which will also evaluate the social impact of the TB detection technology.
Active case finding among high risk population such as prison inmates, miners in remote mining camps, slum dwellers, refugees, etc. is a key component in the fight against TB. This requires screening a substantial number of sputum samples collected from these high-risk populations. Currently available methods are very slow to handle such large numbers in a short period of time. Both operational and research results strongly suggest that rats could be used for screening of such large populations. A single team of rats can process 200 samples per day, if not more, for 200 days per year, which would be sufficient to evaluate more than 40, 000 samples. Therefore, APOPO will further develop the method for deployment as first-line screening tool.