[The history of leprosy and its countermeasures in Norway]

The breakout of leprosy in the history of Norway was influenced by two factors at least. It was partly because Norway was ruled by neighbouring countries for a long time so was underdeveloped, and partly it was a country with temperate marine climate. Leprosy came from Western Europe to Norway during the Viking Age (790-1066 CE) and peaked in the 13^th century when Norway was christianised and fully integrated with Europe with its participation in the crusades. At that time, the Christian Church cared for leprosy patients through its affiliated leprosariums. Leprosy nearly disappeared in Norway in the following two to three centuries because of the effects of the Black Death and the Little Ice Age. In the 19th century, Leprosy peaked again. The Norwegian government began its investigation and scientific research in this period, built up modern leprosariums, developed a leprosy registration system, and implemented strict and legal quarantine measures. Leprosy disappeared in Norway in the first half of the 20^th century. The history of leprosy in Norway showed its protracted and arduous nature, and the great achievements made by the Norwegian government in terms of constructing modern and scientific systems and the prevention and control practices to counter leprosy. This provides experiences and lessons for epidemiology.