disease (leprosy) program Retrieved from There is no recommended test to diagnose latent leprosy in people without symptoms. Few people with latent leprosy test positive for anti PGL-1. The presence of M. leprae bacterial DNA can be identified using a polymerase chain reaction (PCR)-based technique. This molecular test alone is not sufficient to diagnose a person, but this approach may be used to identify someone who is at high risk of developing or transmitting leprosy such as those with few lesions or an atypical clinical presentation. Classification Several different approaches for classifying leprosy exist. There are similarities between the classification approaches. The World Health Organization system distinguishes "paucibacillary" and "multibacillary" based upon the proliferation of bacteria. ("pauci-" refers to a low quantity.) The Ridley-Jopling scale provides five gradations. The ICD-10, though developed by the WHO, uses Ridley-Jopling and not the WHO system. It also adds an indeterminate ("I") entry. In MeSH, three groupings are used. Leprosy may also occur with only neural involvement, without skin lesions. Complications Leprosy may cause the victim to lose limbs and digits but not directly. M. leprae attacks nerve endings and destroys the body’s ability to feel pain and injury. Without feeling pain, people injure themselves on fire, thorns, rocks, and even hot coffee cups. Injuries become infected and result in tissue loss. Fingers, toes, and limbs become shortened and deformed as the tissue is absorbed into the body. Prevention Early detection of the disease is important, since physical and neurological damage may be irreversible even if cured. Medications can decrease the risk of those living with people who have leprosy from acquiring the disease and likely those with whom people with leprosy come into contact outside the home. The WHO recommends that preventive medicine be given to people who are in close contact with someone who has leprosy. The suggested preventive treatment is a single dose of rifampicin (SDR) in adults and children over 2 years old who do not already have leprosy or tuberculosis. Preventive treatment is associated with a 57% reduction in infections within 2 years and a 30% reduction in infections within 6 years. The Bacillus Calmette–Guérin (BCG) vaccine offers a variable amount of protection against leprosy in addition to its closely related target of tuberculosis. It appears to be 26% to 41% effective (based on controlled trials) and about 60% effective based on observational studies with two doses possibly working