Leprosy in 2018: an ancient disease that remains a public health problem today

World Leprosy Day. Image courtest of Wellcome Collection.

28 January 2018 is World Leprosy Day

I have always found leprosy a fascinating disease. It is an incredible example of how microbiology, immunology, and social sciences can collide and impact significantly on human health.

Leprosy has been affecting humans for at least 4000 years. It has played a huge part in teaching us about disease caused by bacteria. In 1873 when Hansen discovered Mycobacterium leprae in tissue samples from patients with leprosy, this became the first bacteria to be directly linked to causing disease in humans. Since then we have developed an understanding of the complex range of types of leprosy that occur depending on how an individual’s immune system responds to the challenge of infection with Mycobacterium leprae. We have also observed the consequences of the deformities and disability caused by the body responding to Mycobacterium leprae, which favours human nerves and skin. In turn, we have seen how the appearance of individuals with disability and disfigurement from leprosy has driven stigma, misinformation, and the discrimination of those affected by the disease.

For many people in the UK and around the world, leprosy, or Hansen’s disease, is an ancient condition of our ancestors. It is something that we hear about in religious scripture or watching films like Ben-Hur or the Life of Brian.  Associated with exile from communities, deformity, and poverty. Something that no longer affects the modern world that we now live in.

Leprosy is often referred to in Sanskrit from around 1400 BC, with the term “kushtha” used to describe it. This translates to “eating away”. Courtesy of Wellcome Collection.

In 2000, the World Health Organisation (WHO) made an announcement that leprosy had been eliminated as a public health issue, with the global prevalence finally falling below one case per 10,000 people. This was the culmination of many years of identifying and treating patients with leprosy. This included the development of multi-drug therapy – a real game-changer in the treatment of Hansen’s disease. In total, over 16 million people affected by leprosy were treated, often free of charge. This was a great success.

And so for the elephant in the room. If we have eliminated leprosy as a public health problem, why do we still need to worry about World Leprosy Day?

(more…)