Discrimination comes in many different forms - but the discrimination we are addressing in London today concerns a disease, leprosy, which goes back to biblical times and, until the early 1980s, was - like HIV AIDs - thought to be incurable.
In the Middle Ages in Britain, there may have been 10,000 leprosy-affected people - isolated, shunned and persecuted. Yet, while leprosy is now completely curable, this age-old discrimination against leprosy-affected people has not changed in many parts of the world.
Leprosy is now not considered a major threat to public health. Only Brazil has not yet achieved the World Health Organisation's elimination target of less than one case per 10,000 people. The number of new cases of leprosy, detected worldwide in 2011, was a little over 219,000.
If the battle to eliminate leprosy is being won, widespread discrimination against leprosy-affected people and their families is still an abuse of their basic human rights. This is why my eighth Global Appeal to end this stigma and discrimination is being launched in London to coincide with the sixtieth anniversary of World Leprosy Day on Sunday.
Helping to perpetuate this discrimination are various existing laws and regulations in many countries of the world. It may be that these laws are not deliberately kept up, but have remained on the statute book, largely forgotten. Some of these laws also date back to a time when public health policy called for the segregation of people with leprosy. This was seen as the only way to protect the health of a nation. But while they exist, these laws help to fan the flames of prejudice and discrimination.
It is therefore significant that the Global Appeal is being launched in London in collaboration with the UK-based International Bar Association (IBA), the world's leading organisation of international legal practitioners, bar associations and law societies - with a global membership of more the 45,000 lawyers and 200 bar associations and law societies.
The IBA will urge its members to help us tackle these discriminatory laws - in countries like Singapore, Nepal, Malta, Thailand and India, where such laws still apply in areas such as contesting elections, marriage and divorce, residential eligibility and employment. On immigration, the United States, China and other countries still refer to leprosy as a reason for declining entry. In fact, only in June last year did the UK Border Agency amend its policy advice to make it clear that having leprosy is not grounds alone for visa refusal.
While India has achieved the WHO's elimination target, because of its population it still accounts for over half of new cases of leprosy. At present there are over 850 colonies in India where people affected by the disease, and their families still live - often in abject poverty.
In London, we are being joined by Vagavathali Narsappa and Guntreddy Venugopal - two leprosy-affected people from India who work tirelessly for the National Forum India of people affected by leprosy, which my organisation, The Nippon Foundation, has helped to fund. Mr Narsappa speaks movingly about the discrimination he has faced after being rejected by his own family as a boy. He recalls the dislike and hatred in the faces of friends and village elders, once he had been diagnosed. People shut their doors when he walked down the street. These attitudes - sadly - still prevail.
In 2010, my campaign received a significant boost when the United Nations General Assembly unanimously adopted a resolution calling for the elimination of discrimination against persons affected by leprosy and their family members. It is now beholden on member nations to ensure that this resolution is enforced.
Of course, I cannot pretend that UN resolutions, however binding, and overturning antiquated legislation, will reverse a discrimination that has lasted for centuries. But at least it gives us a foundation for positive action. Which is why I believe our London Global Appeal is an historic opportunity - and, if we listen to what people affected by leprosy have to say, look inside our hearts and share the pain, we will succeed.
Follow Yohei Sasakawa on Twitter: www.twitter.com/NipponZaidan