Did you know leprosy is a disease as old as civilisation itself? First noted in the literature of ancient civilisations, leprosy has plagued communities and families worldwide for thousands of years – leaving those inflicted with leprosy ostracised and casted away from their families and community; hence, birthing the term lepers. Modern medicine only finally caught up in the 20th century, bringing the global spread of the disease to an end – just as with small pox. Nevertheless, if Mother Nature has ever taught us anything, it would be to never underestimate biology. Like a stain which would never wash away, leprosy still persists even till today.

The origin and evolution of leprosy

The first records of leprosy date back to more than 3000 years ago from the early literature of ancient civilisations. Leprosy, though without a uniform term, was recognised by various civilisations around the globe – with its disfiguring outcomes and segregated infected communities. Some interpreted the disease as a curse of the gods; some as a form of punishment of sin; while others as a hereditary disease. Truth be told, no one really knew. Not for another three millennia, at least.

Leprosy, or Hansen’s Disease, often leaves the infected with permanent disfigurement and nerve damage.
Leprosy, or Hansen’s Disease, often leaves the infected with permanent disfigurement and nerve damage.

Believed to have originated from either the African or Asian continent, leprosy spread throughout Europe due to the conquering armies of Alexander the Great. Ever since then (300BC), leprosy continued to spread throughout the communities of Europe and the Middle East. In major hubs of civilisation, overcrowding, poor sanitation and malnutrition only served to proliferate the spread of leprosy. Without any cure at hand, the incurable and disfigured sufferers of leprosy were often isolated to other communities of lepers in order to quell the spread of the disease.

What about the other side of the globe? During the uprising of colonialism and slavery, leprosy then spread to South America from the African slaves who were transported into the country. With that, leprosy soon became the global pandemic that etched its indelible name into the pages of history.

Gerhard Hansen, the Norwegian physician, who discovered the causative agent of leprosy. Photo credit: US and Culture
Gerhard Hansen, the Norwegian physician, who discovered the causative agent of leprosy. Photo credit: US and Culture

Finally, in 1873, Norwegian physician Gerhard Hansen visualised the presence of leprosy bacillus under a light microscope, effectively proving that leprosy was an infectious disease and not a curse. In light of the discovery, the disease was named after him hence, the name Hansen’s disease.

The next breakthrough would not come until the 1940s where the development of the antibiotic, dapsone, provided the first cure for leprosy. The treatment of leprosy was further refined in the 1960s with the addition of rifampicin and clofazimin. By 1981, the World Health Organisation (WHO) began recommending a multidrug therapy (MDT) consisting of dapsone, rifampicin and clofazimin. With a proven and effective cure at hand, in 1995, the WHO pledged to make MDT treatment free for all leprosy patients worldwide. Two decades have passed since then, and the commitment holds true till today.

Ancient plague in today’s society

Medical textbooks will tell you that leprosy is the result of a chronic infection of mycobacterium leprae which primarily affects the skin, peripheral nerves, mucosa of the upper respiratory tract and the eyes. While the symptoms make take several years to manifest, they are often progressive and permanent.

Because of its debilitating outcomes, early diagnosis and treatment are of paramount importance. More than just MDT, vaccines too have a role to play providing early protection against the disease. For example, the Bacillus Calmette-Guerin (BCG) vaccine confers a degree of protection and is often administered to children. Meanwhile, a new leprosy vaccine developed in India is awaiting approval with hopes to turn the tables on the war against leprosy.

"We do know that it's not highly contagious. You need prolonged contact with an untreated individual," says Ramanuj Lahiri, microbiologist with the US Department of Health and Human Services' National Hansen's Disease Programme. According to Lahiri, 95% of the human population is naturally resistant to leprosy and won't catch it no matter how long they're exposed.

Till date, more than 16 million leprosy patients have been treated with MDT and leprosy was no longer designated as a public health problem (with a prevalence of less than 1 in 10,000 persons) in the year 2000. Despite that, more than 200,000 new cases of leprosy are reported every year with half of these new cases originating from India. If anything, the global combat on leprosy is far from over.

Recognising this, WHO launched the “Global Leprosy Strategy 2016 – 2020: Accelerating towards a leprosy-free world” in 2016. The organisation hopes to double down on their efforts to eradicate leprosy; especially among children affected by the disease in endemic countries. Working together with the Novartis Foundation, they are committed to providing free MDT medication to leprosy patients with a focus on endemic nations. "Transmission seems to go on. The number of new cases has remained stable for the past 10 years," expresses Dr Ann Aerts, Head of Novartis Foundation, reassuring the need to continue the battle on leprosy spread.

Digital technology is also beginning to play a role with early diagnosis of leprosy. Health care workers are able to take pictures of skin patches and send them in for visual diagnosis. This negates the need for a specialist on-site while, allowing for earlier diagnosis. This is absolutely pivotal in the war against leprosy, as if detected early, the disease is very much curable with little major damage having set in yet. Patients who are treated early are able to return to their daily lives quicker with less disabilities bringing a higher quality of living and generating positive boost for the country’s economy.

The bottom line

Getting rid of leprosy is not going to be easy – and it will require a global effort in order to eradicate the disease. Treatment and diagnosis have come a long way. But, there’s still a lot of work to be done – for instance, in strengthening the outreach and community awareness (especially in endemic areas) towards leprosy – as we power our way through in eradicating this ancient disease from the global community. MIMS

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