African Giant Pouched Rats: A Novel Approach to TB Diagnosis

African Giant Pouched Rats: A Novel Approach to TB Diagnosis

Sub :Sci

Sec :Health

Why in 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 annually.
• India accounts for 28% of global TB cases.
• Around 5 lakh deaths occur due to TB in India each year, equating to one death per minute.
• Refer: About Tuberculosis (TB)

Key challenges in TB detection:

• Difficulty in diagnosing TB in early stages and in children.
• Low bacillary loads (M. tuberculosis concentration in sputum) remain undetected.
• Reluctance for secondary testing after an initial negative result.
• Lack of accessible diagnostic facilities in rural and remote areas.
• High cost of travel despite 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 possess highly sensitive olfactory receptors, allowing them to sniff out TB with remarkable accuracy.
• Training Process of HeroRATS: The rats are bred and trained at a specialized facility starting at 2-3 months old.
• Identified samples undergo further confirmation using Ziehl-Neelsen (ZN) microscopy and fluorescent microscopy.

Disease Detection by Animals:

• Dogs: Have 125-300 million olfactory receptors and a Jacobson’s organ to detect pheromones and chemical signals. Used for detecting Parkinson’s disease and other illnesses.
• Ants: Quick learners and cost-effective for cancer detection. A French study (Science Direct) found ants detected cancer cells within three days using chemical cues and sugar rewards.
• Honeybees:Have highly sensitive olfactory lobes.Research from Michigan State University found they can detect lung cancer biomarkers with 88% accuracy.Can 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 part of the olfactory system and are linked to the brain’s olfactory bulb.
• Humans have around 400 types of olfactory receptors, while animals like dogs have up to 300 million.

African Giant Pouched Rats (HeroRATS):

• Scientific Name: Cricetomys ansorgei
• Native to sub-Saharan Africa.
• Large-sized rodents with highly developed olfactory senses.
• Used for detecting landmines in war-affected regions.
• Ongoing research on their potential for detecting drug-resistant TB.