AFRICAN
GIANT POUCHED RATS: SCIENCE & TECHNOLOGY
NEWS: Could African giant
pouched rats offer a solution to the challenges of TB diagnosis?
WHAT’S IN THE NEWS?
A non-profit organization,
APOPO, based in Tanzania, has successfully trained African giant pouched rats
to detect tuberculosis (TB) as a secondary diagnostic tool. Recent studies
indicate that these rats can detect TB twice as effectively as conventional
testing methods, particularly in children.
Global and Indian TB Burden
- Tuberculosis (TB) is one of the deadliest
infectious diseases globally, with over 10 million new cases reported
annually.
- India accounts for 28% of the global TB cases,
making it a significant public health challenge.
- Around 5 lakh deaths occur due to TB in India
every year, equating to one death per minute.
Key Challenges in TB Detection
- Difficulty in diagnosing TB in early stages,
especially in children.
- Low bacillary loads (M. tuberculosis
concentration in sputum) often go undetected in conventional tests.
- Many individuals do not opt for secondary
testing after receiving an initial negative result.
- Lack of accessible diagnostic facilities in
rural and remote areas.
- High cost of travel to healthcare centers,
despite the availability of free treatment.
The Role of African Giant
Pouched Rats in TB Detection
- APOPO, a Tanzanian non-profit, trains African
giant pouched rats (nicknamed HeroRATS) to detect TB in sputum samples.
- These rats have highly sensitive olfactory
receptors, enabling them to identify TB with high accuracy.
- Research indicates that these rats can detect
TB at twice the efficiency of conventional testing methods.
Training Process of HeroRATS
- The rats are bred and trained at specialized
facilities, beginning their training at 2-3 months of age.
- The training involves exposure to TB-positive
and TB-negative sputum samples, rewarding correct identification.
- Once trained, the rats analyze sputum samples
rapidly and indicate TB-positive samples by scratching at them.
- Identified samples undergo further confirmation
using Ziehl-Neelsen (ZN) microscopy and fluorescent microscopy.
Disease Detection by Animals
- Dogs: With 125-300 million olfactory receptors
and a Jacobson’s organ, they are used for detecting diseases like
Parkinson’s.
- Ants: Quick learners and cost-effective for
cancer detection. A French study found ants detected cancer cells within
three days using chemical cues and sugar rewards.
- Honeybees: Research from Michigan State
University found they can detect lung cancer biomarkers with 88% accuracy
and distinguish between small-cell lung cancer (SCLC) and non-small cell
lung cancer (NSCLC).
Olfactory Receptors
- Olfactory receptors are specialized protein
molecules found in the sensory neurons of the nose.
- They detect and respond to chemical odorants in
the air, enabling the sense of smell.
- These receptors are linked to the brain’s
olfactory bulb and play a crucial role in detecting diseases.
- Humans have around 400 types of olfactory
receptors, while animals like dogs have up to 300 million, making them far
superior in scent detection.
African Giant Pouched Rats
(HeroRATS)
- Scientific Name: Cricetomys ansorgei
- Native to sub-Saharan Africa and known for
their exceptional sense of smell.
- Large-sized rodents with highly developed
olfactory senses, making them suitable for scent-based detection tasks.
- Used for detecting landmines in war-affected
regions, proving their effectiveness in life-saving missions.
- Ongoing research explores their potential for
detecting drug-resistant TB, which poses a significant challenge to global
TB control efforts.
Source: https://www.thehindu.com/sci-tech/health/could-african-giant-pouched-rats-offer-a-solution-to-the-challenges-of-tb-diagnosis/article69265333.ece