Using Pouched Rats to Detect Landmines and Tuberculosis: Research Findings and Practical Applications

Transcription

1 Using Pouched Rats to Detect Landmines and Tuberculosis: Research Findings and Practical Applications Alan Poling, Ph.D., BCBA-D Western Michigan University and Anti-Persoonsmijnen Ontmijnende ProductOntwikkeling (Anti-Personnel Landmines Detection Product Development, APOPO) APOPO is a Belgian NGO Its strategic goal is to save lives through the deployment of scent-detection rats. Its specific goals are: To deploy cost-efficient mine action solutions. To accelerate tuberculosis (TB) diagnosis. To develop and deploy innovative detection-rats technology. Its success is substantial: About 26,500,000 square meters of land returned to locals. About 70,000 explosive devices located and destroyed. About 9,000 new cases of TB detected. Bart Weetjens, Founder of APOPO, with a Rat Christophe Cox, APOPO CEO, with a Rat Student Colleagues Amy Durgin, Ph.D. Tim Edwards, Ph.D. Kate La Londe, Ph.D. Amanda Mahoney, Ph.D. Erin Watkins, M.A. Members of the TB Research Team 1

2 Some Members of the Mozambique Demining Team Adult rats are about 45 cm long and weight 1-2 kg There are million landmines in 75 countries They kill or injure 15-20,000 people each year Minewolf Tiller Tuberculosis (TB): Still a scourge Tuberculosis, caused by Mycobacterium tuberculosis: Infects two billion people worldwide Infects nine million new people each year Causes two million deaths each year Responds favorably to antibiotics in most cases Poses a serious diagnostic challenges in developing countries, where it is most common (e.g., worldwide prevalence is 137 TB-positive cases per 100,000, Tanzanian prevalence is 465 per 100,000) Slide showing Mycobacterium tuberculosis 2

3 Steps in Training Landmine-detection Rats Clicker training One- and three-hole training to establish 2,4,6- trinitrotolune (TNT) as a discriminative stimulus Training with tea balls Training on the simulated minefield in Tanzania Early handling Training when the rat arrives in country Continuous testing and training of operational animals TB-Detection Apparatus APOPO Hero Rats Detecting Land Mines TB Detection Video The Mine Sniffing Rats of Tanzania 3

4 Three Questions worth Answering: 1. How good is current performance? 2. How can performance be improved? 3. How can applications be extended? Quality Control is Paramount In 2009, we conducted a large quality control operation where rats checked 93,400 m 2, finding 95 landmines and other ERW Humans using metal detectors found no additional mines in this area We just completed a quality control study where the rats found 58 mines and mine fragments in a 28,050 m 2 tilled area Humans using metal detectors found no additional mines in this area The false alarm rate in both studies was less than 0.5 per 100 m 2 A 2010 study involving sputum samples from 12,329 patients from DOTS centers revealed that: 1. DOTS centers found TB in 1,403 patients (13.3%) 2. Rats identified TB in 1,335 of those patients (95%) and in an additional 620 patients, increasing new-case detections by 44% A 2011 study involving sputum samples from 26,658 patients from DOTS centers revealed: 1. DOTS centers found TB in 1,671 patients (13.6%) 2. Rats identified TB in 1,547 of those patients (93%) and in an additional 716 patients, increasing new-case detections by 43% In another study: Culturing/PCR detected M. tuberculosis in 154 sputum samples from 100 patients Microscopy detected 58% of TB-positive patients On average, 10 individual rats detected 70.5% of TBpositive patients Detections increased when groups of rats were used Our TB research shows that: Rats can detect MTB in fixed microscope slides, but not well Adding more low-concentration MTB samples increases detection of such samples Adding a sodium phosphate buffer to sputum samples does not affect MTB detection Sensitivity and specificity of MTB detection can be altered by changing the criterion for rat indications Performance deteriorates when fewer than 2% of samples provide an opportunity for reward A reinforcement-for-agreement procedure may work Agreement is good within and between rats TB is more often detected in men than in women Intra-rat reliability is very high, inter-rat reliability is moderately high Male rats may be a bit more accurate than females 4

5 Cumulative Cases - Tanzania Cumulative Cases - Mozambique The TB-detection rats are of practical value Results from Maputo, Mozambique Clinic 1800 Clinic Clinic + Detection Rats 5000 Clinic + Detection Rats Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Our landmine-detection research shows that: A TNT soaking procedure is useful for maintaining performance Neutering does not affect performance Rats are great for technical survey Rats can work on a pole Rats Can Work on a Pole Other research shows that: The rats can detect salmonella in horse feces The rats can detect cigarettes and other tobacco products The rats can be taught to search for and find people We are investigating other potential uses of the rats: Detecting cancer (e.g., cervical cancer in underserved populations) Detecting PTSD, Alzheimer s disease, and Parkinson s disease A problem is that many training samples are needed, which poses a challenge with many difficult-to-diagnose diseases 5

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