Leprosy: the ancient disease scientists can’t solve

If an effective rapid diagnostic test were available – one that was non-invasive and effective, many of these missing cases of leprosy and close contacts of patients could be diagosed, without the need for blanket prescriptions of rifampicin to potentially healthy individuals. The good news is that these diagnostic tests are currently under development – though they may not be available for some time.  

To study the disease and its progression and develop diagnostic tests, scientists often need to inject M. leprae into armadillos, a technique that was first attempted in 1971. “The fact that we cannot culture [grow] this bacteria so easily in laboratory settings is another factor hindering the progress of developing these tests,” says Sunkara. 

New horizons

Since 2000, Novartis Foundation has partnered with the WHO, supplying drugs free of cost globally for multi-drug therapy. In February 2022, they partnered with Fiocruz for a study that uses artificial intelligence (AI) to accelerate leprosy diagnosis. “I call it applying state-of-the-art technology to an ancient disease,” says Sunkara.  

There are at least 20-30 other skin diseases that present as white patches on the skin, says Sunkara. Using the AI algorithm to analyse the way light reflects differently off the surface of each skin disease, it’s possible to identify leprosy cases, distinguishing them from other similar conditions with far more accuracy. Their study, published in Lancet Regional Health, pegged the accuracy at 90% – but with 1,229 skin images, the data set remains small at the moment.  If it succeeds on a larger scale, it might one day be a useful tool to help speed up diagnosis and treatment. 

Continuing stigma

While modern advances in the treatment and diagnosis of leprosy have been life-changing for many patients, there’s one problem that has never quite gone away: relentless discrimination. 

“Leprosy remains a deep-rooted human rights issue,” says Alice Cruz, the UN Special Rapporteur on the elimination of discrimination against persons affected by leprosy, a role she’s held since November 2017. There are more than a hundred laws that discriminate against people with leprosy worldwide, creating a strong stigma that can act as a barrier for getting treatment, she says. 

In some countries, leprosy is grounds for divorce. In India, this was the case until laws were amended in 2019. Many people affected by the disease still struggle to get jobs, and the disease can hinder their access to healthcare and education.

“Countries should do everything in their power to have discriminatory laws abolished and to put in place policy that can guarantee economic and social rights to people affected by leprosy,” says Cruz. “Going forward, we should ask ourselves the question: are our healthcare systems working to afford full accessibility to persons affected by leprosy? This is because leprosy is much more than a disease, it became a label that dehumanises people who are affected by it.”

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