Context: 

To address the limitations of conventional TB diagnostics, APOPO, a non-profit organization based in Tanzania, has pioneered an innovative approach—training African giant pouched rats (Cricetomys ansorgei), commonly known as HeroRATS, to detect TB. These rats possess highly sensitive olfactory receptors, allowing them to accurately identify TB-positive samples, particularly in cases where traditional methods fall short.

Scientific Validation

A study published in BMC Infectious Diseases (April 2023) examined 35,766 patients in Tanzania. Of these, 5.3% (1,900 cases) were smear-positive, while 94.7% (33,866 cases) were smear- or Xpert-negative.

The rats detected an additional 2,029 TB cases, which would have otherwise gone unnoticed. The study also found that the rats could detect TB at twice the rate of conventional testing in children and were six times more effective in identifying low bacillary loads (scanty or 1+) compared to higher bacillary loads (2+ or 3+).

One of the key advantages of this method is speed. HeroRATS can screen 100 samples in just 20 minutes, whereas a human technician using conventional sputum-smear microscopy requires three to four days to process the same number of samples. This rapid detection method enhances early diagnosis, allowing for quicker treatment initiation and reduced transmission rates.

Animals in Disease Detection beyond TB

• • Dogs: With 125–300 million olfactory receptors and a specialized Jacobson’s organ for detecting pheromones, dogs have been trained to identify diseases such as Parkinson’s disease through scent-based analysis.
  • Ants: A French study (published in Science Direct) demonstrated that ants can detect cancer cells within three days using chemical cues and a sugar reward system. Their ability to distinguish between different cancer types highlights their potential in cost-effective, rapid diagnostics.
  • Honeybees: Research conducted by Michigan State University revealed that honeybees can detect lung cancer using synthetic biomarkers. Changes in neural activity in their antennal lobes allow them to differentiate between small-cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) with 88% accuracy.

Challenges

·        Regulatory approvals and government collaboration with APOPO to ensure program viability.

·        Adaptation of logistics and infrastructure to accommodate rat-based screening within diagnostic centers.

·        Public awareness campaigns to address cultural and ethical concerns regarding the use of animals in disease detection.

·        Further validation through pilot programs in select high-TB burden states to assess feasibility and effectiveness.

About Tuberculosis (TB):

 Tuberculosis (TB) remains a major global health concern, with over 10 million new infections annually. India bears a significant burden, accounting for 28% of the world’s TB cases, with approximately 500,000 deaths per year—equivalent to one TB-related death every minute. Despite medical advancements, early detection remains a challenge, particularly in remote and underserved populations.

·         The National TB Elimination Programme (NTEP) aims to eradicate TB in India by 2025, five years ahead of the global target of 2030. While the India TB Report 2024 shows a 16% decline in TB incidence and an 18% reduction in TB-related deaths since 2015, complete elimination remains elusive.

Conclusion

India continues to struggle with high TB prevalence, particularly in rural and underserved areas where early detection remains a challenge. While TB treatment is free, the cost of travel to healthcare facilities remains a significant barrier to timely diagnosis. Traditional diagnostic methods are slow and often unreliable, making alternative approaches essential. HeroRATS, with their proven efficiency in TB detection, could serve as a valuable secondary screening tool.