Li Zhidi has lost most of her fingers. [Photos by Feng Yongbin / China Daily]

Many people mistakenly believe that leprosy has been eradicated. It has an almost historical aura and even the name suggests an ailment from an earlier era. But for sufferers, the disease is a reality they must live with every day.

Leprosy, also known as Hansen's disease, has afflicted humanity for more than 4,000 years. It is caused by bacteria, Mycobacterium leprae, that damage the skin, nerves, limbs and eyes. The disease can result in severe scarring, especially on the face and limbs.

The symptoms can take months or even years to appear. The limbs of the afflicted person lose all sensitivity, resulting in easy damage to extremities such as fingers and toes. Sometimes, tissue loss results in shortened fingers and legs.

The disease was first recorded in China 2,000 years ago, and as late as the 1940s it was endemic in some coastal areas and in the southwest of the country. Guangdong province was the epicenter, home to one in four of the country's lepers. In 1949, Guangdong had at least 40,000 sufferers and the disease was targeted by eight hospitals, most of which were founded by missionaries.

Like many countries in the 1950s, China viewed forced isolation as the best option to protect healthy residents from infection. However, since the 1980s, drugs have been developed to treat the disease.

At present, China has around 600 leper colonies, scattered across several provinces including Yunnan, Sichuan and Jiangxi. Most colonies are located on islands or mountaintops, places cut off from the rest of society, which can only be reached after strenuous effort. Between 25 and 100 people live in each village, in straw or mud-and-brick houses built around a central courtyard. The average age of the residents is 60. Conditions are usually harsh.

It is believed that around 95 percent of people are naturally immune to leprosy, and recent research suggests that a defect in cell-mediated immunity is responsible for susceptibility to the disease.

Those in areas where the illness is endemic are most at risk. The spread may also be exacerbated by contact with contaminated water, poor diet and other factors that can compromise the immune system. Some researchers have even argued that inadequate bedding may put potential sufferers at risk.

According to the World Health Organization, early diagnosis and treatment with multidrug therapy are among the most effective methods of preventing the disease and slowing its spread.

yangwanli@chinadaily.com.cn