Today is World Tuberculosis Day. As we spare a thought for those affected, we also reflect on the countless animals who continue to suffer and die in cruel and fruitless research on this deadly disease.

Sadly, scientists have used animals in tuberculosis (TB) research for over a century. Yet we do not seem to be any closer to eliminating the disease than we were back then. We are still using the same vaccine that we had in the 1920s, and the same drugs that we had in the 1970s!¹

In 2014, there were 9.6 million cases of active TB infection. This resulted in 1.5 million deaths, mainly in underdeveloped countries such as India.²

Despite the development of a vaccine and various drugs to control the disease, TB remains a global threat to public health.  This is due to poor vaccine protection rates and increasing antibiotic resistance.

Much current research focuses on trying to improve the available treatments by:

• injecting animals with TB-causing bacteria, or
• forcing them to inhale it before attempting to treat them with various drugs.

Mice, guinea pigs, rabbits and monkeys are all used in TB experiments.

In 2014, we exposed cruel TB tests being carried out on monkeys at the UK Government owned Porton Down defence research laboratory. These experiments involved injecting monkeys with the BCG vaccine before sedating them and placing them inside chambers where they were forced to inhale the TB-causing bacteria. The animals were studied for months at a time and subjected to repeat blood sampling and sedation.

Those who did not receive the vaccine developed active TB disease and had to be killed early. And those who managed to survive until the end of the study period were killed anyway.³

No animal experiment is able to replicate TB infection and disease as it occurs in humans due to substantial differences in TB susceptibility and disease progression.⁴

Animals are not natural hosts for the TB-causing bacteria and therefore have to be artificially infected, which is not reflective of the human situation. For example, mice are generally resistant to TB infection when compared to humans and are able to tolerate a large amount of the bacteria without becoming unwell. This partly explains why we are still struggling to combat the disease.

Clearly animal experiments are the not the answer and if we hope to make any real progress in the future, a new approach is needed.

For example, researchers in the USA are exploring the use of the ‘lung-on-a-chip’ to study lung function and infections, including TB.⁴ This innovative little device was awarded Design of the Year 2015 by the London Design Museum and holds huge promise for providing a more humane and reliable way to study human disease.⁵

Sources

1. Animal models of tuberculosis. (2005). Tuberculosis, 85(5-6): 277-293.
2. Tuberculosis – Factsheet No 104. (2015). World Health Organisation: http://www.who.int/mediacentre/factsheets/fs104/en/
3. Evidence for a role for interleukin-17, Th17 cells and iron homeostasis in protective immunity against tuberculosis in cynomolgus macaques. (2014). PLoS One, 9(2): e88149.
4. What animal models teach humans about tuberculosis. (2008). American Journal of Respiratory Cell & Molecular Biology, 39(5): 503-508.
5. Novel in vitro respiratory models to study lung development, physiology, pathology and toxicology. (2013). Stem Cell Research & Therapy, 4(1):S7.
6. The end of animal testing? Human-organs-on-chips win Design of the Year. (2015). The Guardian, 22 June: http://www.theguardian.com/artanddesign/2015/jun/22/the-end-of-animal-testing-human-organs-on-chips-win-design-of-the-year 

Photo © Wyss Institute at Harvard University