The end of leprosy: a new test could save millions of lives

Published: Saturday, Feb. 23 2013 2:00 p.m. MST

A new test for leprosy could be the end of a disease that has plagued humanity for more than 4,000 years.

Leprosy, which is also called Hansen's disease, is a chronic infectious disease caused by acid-fast, rod-shaped bacteria, according to the World Health Organization.

The disease mainly affects the skin, peripheral nerves, upper respiratory tract and eyes. The World Health organization notes that skin lesions are the primary external sign of advanced leprosy. A person may be infected with the bacteria for 10 years before any symptoms appear.

Leprosy can be cured with multidrug therapy. Infected persons can avoid disability and disfigurement provided they receive treatment in the early stages of infection, according to the WHO. But until recently, diagnosing leprosy has been extremely difficult.

"The disease has historically been hard to diagnose, despite the popular, but inaccurate, image of fingers and toes dropping off victims," reported the New York Times. It added, "The disease is commonly misdiagnosed, and a person with leprosy may squander critical months, even years, getting useless treatments. By the time a clinician clues in, the patient may be disfigured, blind, maimed or crippled."

The standard diagnostic procedure is to cut open nodules, often in the earlobe, and look for the bacteria under a microscope, according to a Slate report. In addition to being time-consuming and expensive, "trained microscope diagnosticians are rare in the rural areas where the disease persists," the report said.

The new test is fast, simple and inexpensive: one drop of blood goes into a well on a plastic test strip followed by three drops of solution. Within 10 minutes, the results are back.

“It works like a pregnancy test and requires just one drop of blood,” said test developer Malcolm S. Duthie in an interview with the New York Times. “I can teach anyone to use it," he added.

Perhaps the most important aspect of Duthie's innovation, however, is that it can detect infections as much as a year before symptoms appear. The earlier the treatment begins the better the outcome, the New York Times reported.

"The test … come(s) at a critical time for the disease, which has been on the wane thanks to massive public health campaigns to distribute free multidrug therapy," according to Slate. Since 1991, there has been a 90 percent decrease in leprosy prevalence, according to the World Health Organization. Still, active leprosy cases and leprosy-related disabilities affect more than 4 million people worldwide. Since around 2000, the number of new cases reported each year is around 200,000.

However as Slate reports, some experts dispute those figures, arguing they are far too conservative. “I believe that the problem is as large as 1.5 million to 2 million cases, Duthie said in an interview with Slate. "Another reason experts believe the actual number of cases may be higher than WHO claims is that the age-old stigma of the disease, long considered a curse, deters people from seeking medical help. Patients who are cured but disfigured often remain ostracized, even from their own families," they said.

In countries where leprosy is a problem, such as India and Brazil that have fast growing populations, experts worry the floodgates of disease are about to bust open, according to Duthie.

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