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I’ve just come across a really interesting project that I think we can all get behind: tuberculosis-sniffing rats.
It started with land mines. In many war-torn regions in Africa, people cannot access their land for agriculture because it is riddled with mines left over from previous conflicts. Bart Weetjens, a Belgian product development engineer with some experience of the difficulties of living in rural Africa, came across American experiments from the 1970s using gerbils to sniff out explosives. This inspired him to look into using rats to sniff out land mines. In 1997, he founded a nonprofit called Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling (APOPO) and received funding from the Belgian government to pursue his research.
Weetjens settled on using African giant pouch rats to sniff out land mines. The rats were inexpensive, intelligent, plentiful, sociable, trainable, and, most importantly, light enough to not set the land mines off. In 2003, they first tested the rats on real fields with real land mines in Mozambique. Now, they’ve received the backing of international peace agencies and have, to date, rendered safe 2.5 million square-meters of land area in Mozambique, effectively returning 100,000 people to their lands.
Given the success of this project, and the prevalence of pulmonary tuberculosis (TB) in the same communities affected by land mines, Weetjens thought of expanding the project into detection of tuberculosis from sputum samples. The premise is that Mycobacterium tuberculosis emits volatile organic compounds that the rats, with more genetic material dedicated to olfaction than any other mammal, might be able to detect.
It’s a fascinating demonstration of the intersection between science fiction and reality. You have to watch the videos to believe it, but the organization has trained several dozen rats in Tanzania and Mozambique to sniff out TB. It takes the rats 20 msec to sniff out and correctly identify a sample. The rats are able to process in 7 minutes the number of samples that a lab technician (or a lab "rat," if you will) would take a day to process using conventional light microscopy methods. In Dar es Salaam, using samples from more than 10,500 people from five hospitals, they increased the case detection rate by 44% over that of conventional microscopy. This method has a sensitivity of about 85% and a specificity of 90% – about the same rates as a 10-mm positive tuberculin test (Am. J. Trop. Med. Hyg. 2010;83:1308-10). It is even able to distinguish between M. tuberculosis and other mycobacterial species.
According to the World Health Organization, people with active tuberculosis can spread the disease to 10-15 close contacts in a year. WHO also says that TB is the second biggest infectious killer (behind HIV) worldwide, with over 1.3 million deaths in 2012. If these rats can really detect patients with TB at a much higher rate and with a greater sensitivity than standard microscopy, imagine the impact they would have on reducing the number of deaths worldwide from TB, especially in African nations where TB and HIV often co-occur, and access to health care is difficult.
APOPO’s project is a wonderful example of how simple innovations in science can have such a large footprint on global health. If you’re interested in learning more about APOPO, visit their website. You’ll find interesting videos and links to publications, plus ways to donate.
Dr. Chan practices rheumatology in Pawtucket, R.I.
I’ve just come across a really interesting project that I think we can all get behind: tuberculosis-sniffing rats.
It started with land mines. In many war-torn regions in Africa, people cannot access their land for agriculture because it is riddled with mines left over from previous conflicts. Bart Weetjens, a Belgian product development engineer with some experience of the difficulties of living in rural Africa, came across American experiments from the 1970s using gerbils to sniff out explosives. This inspired him to look into using rats to sniff out land mines. In 1997, he founded a nonprofit called Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling (APOPO) and received funding from the Belgian government to pursue his research.
Weetjens settled on using African giant pouch rats to sniff out land mines. The rats were inexpensive, intelligent, plentiful, sociable, trainable, and, most importantly, light enough to not set the land mines off. In 2003, they first tested the rats on real fields with real land mines in Mozambique. Now, they’ve received the backing of international peace agencies and have, to date, rendered safe 2.5 million square-meters of land area in Mozambique, effectively returning 100,000 people to their lands.
Given the success of this project, and the prevalence of pulmonary tuberculosis (TB) in the same communities affected by land mines, Weetjens thought of expanding the project into detection of tuberculosis from sputum samples. The premise is that Mycobacterium tuberculosis emits volatile organic compounds that the rats, with more genetic material dedicated to olfaction than any other mammal, might be able to detect.
It’s a fascinating demonstration of the intersection between science fiction and reality. You have to watch the videos to believe it, but the organization has trained several dozen rats in Tanzania and Mozambique to sniff out TB. It takes the rats 20 msec to sniff out and correctly identify a sample. The rats are able to process in 7 minutes the number of samples that a lab technician (or a lab "rat," if you will) would take a day to process using conventional light microscopy methods. In Dar es Salaam, using samples from more than 10,500 people from five hospitals, they increased the case detection rate by 44% over that of conventional microscopy. This method has a sensitivity of about 85% and a specificity of 90% – about the same rates as a 10-mm positive tuberculin test (Am. J. Trop. Med. Hyg. 2010;83:1308-10). It is even able to distinguish between M. tuberculosis and other mycobacterial species.
According to the World Health Organization, people with active tuberculosis can spread the disease to 10-15 close contacts in a year. WHO also says that TB is the second biggest infectious killer (behind HIV) worldwide, with over 1.3 million deaths in 2012. If these rats can really detect patients with TB at a much higher rate and with a greater sensitivity than standard microscopy, imagine the impact they would have on reducing the number of deaths worldwide from TB, especially in African nations where TB and HIV often co-occur, and access to health care is difficult.
APOPO’s project is a wonderful example of how simple innovations in science can have such a large footprint on global health. If you’re interested in learning more about APOPO, visit their website. You’ll find interesting videos and links to publications, plus ways to donate.
Dr. Chan practices rheumatology in Pawtucket, R.I.
I’ve just come across a really interesting project that I think we can all get behind: tuberculosis-sniffing rats.
It started with land mines. In many war-torn regions in Africa, people cannot access their land for agriculture because it is riddled with mines left over from previous conflicts. Bart Weetjens, a Belgian product development engineer with some experience of the difficulties of living in rural Africa, came across American experiments from the 1970s using gerbils to sniff out explosives. This inspired him to look into using rats to sniff out land mines. In 1997, he founded a nonprofit called Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling (APOPO) and received funding from the Belgian government to pursue his research.
Weetjens settled on using African giant pouch rats to sniff out land mines. The rats were inexpensive, intelligent, plentiful, sociable, trainable, and, most importantly, light enough to not set the land mines off. In 2003, they first tested the rats on real fields with real land mines in Mozambique. Now, they’ve received the backing of international peace agencies and have, to date, rendered safe 2.5 million square-meters of land area in Mozambique, effectively returning 100,000 people to their lands.
Given the success of this project, and the prevalence of pulmonary tuberculosis (TB) in the same communities affected by land mines, Weetjens thought of expanding the project into detection of tuberculosis from sputum samples. The premise is that Mycobacterium tuberculosis emits volatile organic compounds that the rats, with more genetic material dedicated to olfaction than any other mammal, might be able to detect.
It’s a fascinating demonstration of the intersection between science fiction and reality. You have to watch the videos to believe it, but the organization has trained several dozen rats in Tanzania and Mozambique to sniff out TB. It takes the rats 20 msec to sniff out and correctly identify a sample. The rats are able to process in 7 minutes the number of samples that a lab technician (or a lab "rat," if you will) would take a day to process using conventional light microscopy methods. In Dar es Salaam, using samples from more than 10,500 people from five hospitals, they increased the case detection rate by 44% over that of conventional microscopy. This method has a sensitivity of about 85% and a specificity of 90% – about the same rates as a 10-mm positive tuberculin test (Am. J. Trop. Med. Hyg. 2010;83:1308-10). It is even able to distinguish between M. tuberculosis and other mycobacterial species.
According to the World Health Organization, people with active tuberculosis can spread the disease to 10-15 close contacts in a year. WHO also says that TB is the second biggest infectious killer (behind HIV) worldwide, with over 1.3 million deaths in 2012. If these rats can really detect patients with TB at a much higher rate and with a greater sensitivity than standard microscopy, imagine the impact they would have on reducing the number of deaths worldwide from TB, especially in African nations where TB and HIV often co-occur, and access to health care is difficult.
APOPO’s project is a wonderful example of how simple innovations in science can have such a large footprint on global health. If you’re interested in learning more about APOPO, visit their website. You’ll find interesting videos and links to publications, plus ways to donate.
Dr. Chan practices rheumatology in Pawtucket, R.I.