Leprosy Fades to Painful Past Around Globe
Leprosy is one of the oldest known diseases and one of the most misunderstood. It has plagued humans since pre-biblical days, and victims have suffered not only the ravages of the disease but also severe social stigma.
Today the disease is close to elimination.
Until recent years, leprosy symptoms were often thought to be a punishment from God for a person’s sins, and no treatments were known. Victims--the “unclean”--suffered ostracism, inability to work and forced separation from their families. They had virtually no hope of cure or of a return to normality.
As recently as the 1960s, leprosy patients were still being segregated in isolated facilities--such as the now-closed leprosarium in Carville, La.--where they were cared for but not cured.
But the development of new antibiotics that target the leprosy bacterium changed the situation. In 1991, the World Health Organization set a goal of eliminating leprosy from the world within 15 years. The group recently announced that it had met the first major milestone in its quest, the elimination of 90% of all leprosy cases.
Already, the WHO program has cured 11 million leprosy patients, bringing the total number of cases worldwide down to around half a million. Nonetheless, because of continuing infections, researchers predict it will be necessary to cure 2.5 million more people by 2005 to come close to eradicating the disease.
“Never before have we had such an opportunity to eliminate leprosy,” says Dr. Klaus M. Leisinger, executive director of the Novartis Foundation for Sustainable Development, which is donating drugs for the program. “We can do it. We must do it.”
“Today no one should have to suffer the stigma, deformity and disability wrought by this curable disease,” added Dr. Gro Harlem Brundtland, WHO director-general.
The majority of the world’s remaining leprosy cases are found in only six countries: Brazil, India, Madagascar, Mozambique, Myanmar and Nepal. Nearly 70% of the cases are in India alone, and that country is committed to bringing it under control, according to Dr. Chandreshwar Prasad Thakur, union minister for health and family welfare. He predicts that the goal of dramatically reducing incidence will be met by 2005.
The United States had 108 cases of leprosy in 2000, according to the Centers for Disease Control and Prevention. Most of those cases were in immigrants, but some were caused by handling armadillos. That animal is the only wild species that carries the disease, and armadillos in Louisiana and East Texas are known to be infected.
With the newest antibiotic treatments, leprosy can be cured with a one-day treatment provided it is caught in its earliest stage, when there is no more than one blotch on the skin, according to Dr. Tore Godal of UNICEF in Geneva. But full use of the new treatment, he added, will require a much wider use of a new diagnostic procedure, similar to the tuberculin skin test, to identify infected individuals before the disease has progressed.
Leprosy is an infectious disease that affects principally the skin and the peripheral nerves. The most visible signs are white patches on the skin. People with the milder form of the disease, called paucibacillary leprosy, generally have fewer than six patches, while those with the more severe form, multibacillary leprosy, have six or more.
The disease can damage the lungs and other organs, but the major damage is to the nerves of the arms and legs. Because of lost sensation, victims often burn themselves severely or otherwise accidentally harm themselves. As many as 2 million people worldwide are considered permanently disabled as a result of the disease. Contrary to mythology, however, the disease does not cause arms and legs to fall off.
Leprosy is caused by a bacterium called Mycobacterium leprae , which is closely related to the bacterium that causes tuberculosis. M. leprae was identified in 1873 by the Norwegian physician Gerhard H.A. Hansen, making it the first bacterium known to cause disease. Consequently, leprosy is now more formally called Hansen’s disease.
But knowing what caused leprosy did physicians little good for 70 years. Only then did researchers develop dapsone, one of the first antibiotics and the first to kill M. leprae . But dapsone was mediocre at best. Patients had to take it for very long periods, often for life. Many patients missed doses or stopped taking it, and by the 1960s resistance to the drug began to develop in the bacterium.
The major breakthrough in treatment occurred in the early 1960s when Novartis Pharmaceuticals Corp. developed the antibiotics rifampicin and clofazimine, both of which are effective against M. leprae . A combination of the three antibiotics cures paucibacillary leprosy in six months and multibacillary leprosy in 12 months.
Patients lose their infectiousness as soon as they begin treatment, although the most infectious stage of the disease occurs before symptoms appear. There are few side effects to the treatment and virtually no relapses once treatment is halted. Researchers have seen little resistance developing to the new regimen.
Novartis also developed a blister pack for the antibiotics, which protects them from tropical humidity, allowing patients to take a supply of drugs home, which improves their adherence to the regimen.
The ability to cure the disease and the ready availability of the drugs have dramatically reduced the stigma associated with the disease, Godal said. People now come forward readily when they have symptoms, he said, and screening programs are widely attended.
Research continues with M. leprae , but it is a very difficult bacterium to work with. Bacteriologists have never been able to grow it successfully in a laboratory dish, so the armadillo has been a valuable laboratory animal. Researchers at the CDC also developed a technique for growing the bacterium in the rear footpads of mice.
One problem is its very slow growth rate, according to Dr. Arvind Dhople of the Florida Institute of Technology in Melbourne. The common laboratory bacteria Escherichia coli ( E. coli ), for example, replicates every 15 to 20 minutes. The tuberculosis bacterium replicates every five to seven hours. But M. leprae requires 21 to 28 days, greatly slowing any research projects.
Nonetheless, Dhople and others have found that newer antibiotics, such as minocycline and fluoroquinolones, are useful against the disease. The combination of rifampacin, minocycline and a fluoroquinolone is the therapy used to eliminate leprosy in its earliest stage.
One indicator of growing success is that not many researchers are studying leprosy anymore, said Godal. Many of those who were researching leprosy have now switched to tuberculosis because of the severe drug resistance problem that is developing with that disease.
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More information is available on the Internet at https://www.who.int and https://www.foundation.novartis.com.
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Maugh can be contacted at thomas.maugh@latimes.com.
