Leprosy

Treatments for leprosy have improved considerably over the past 40 years. In fact, some experts believe that the drug regimens being tested in various trials throughout the world (including the United States) may eradicate leprosy completely by the year 2000. Beginning in the 1950s, an antibiotic called dapsone was used to treat leprosy, offering the first hope of a cure for persons with the disease. Dapsone's main disadvantage was that the patient had to take the medication daily throughout his or her lifetime. In addition, the M. leprae in some patients underwent genetic mutations that rendered it resistant to the antibiotic. In the 1960s, the problem of resistance was tackled with the advent of multidrug therapy. Bacteria are less likely to become resistant to several drugs given in combination. The new multidrug treatment time was also considerably shorter-typically about four years. Currently, researchers are experimenting with a new drug combination which includes an antibiotic called oflaxicin. Oflaxicin is a powerful inhibitor of certain bacterial enzymes that are involved in DNA coiling. Without these enzymes, the M. leprae cannot copy the DNA properly and the bacteria die. The treatment time for this current regimen is about four weeks—the shortest time so far.

One risk of treatment, however, is that antigens—the proteins on the surface of M. leprae that initiate the host immune response—are released from the dying bacteria. In some people, when the antigens combine with antibodies to M. leprae in the bloodstream, a reaction called erythema nodosum leprosum may occur, resulting in new lesions and peripheral nerve damage. Some leprosy experts are experimenting with the drug thalidomide to treat this reaction, with good results. But because thalidomide causes severe birth defects, women of childbearing age must be carefully monitored while taking the drug.