Tuberculosis continues to afflict millions | Science| In-depth reporting on science and technology | DW | 23.03.2012
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Science

Tuberculosis continues to afflict millions

As the world marks the discovery of what causes TB, the disease persists in underdeveloped regions. Tuberculosis has largely been eliminated from areas with better health care, due to vaccines and antibiotics.

On Saturday, the public health community marks World Tuberculosis Day; a commemoration held each year on March 24 in honor of German scientist Robert Koch, who discovered the bacterial cause of tuberculosis.

On March 24, 1882, Koch presented his findings to German scientists, and published them in a local medical journal the following month. This finding later earned him the Nobel Prize for Medicine.

Tuberculosis (TB) is a highly infectious and often deadly disease caused by bacteria that affect the lungs. In the late 19th-century, the disease was relatively common, even in Europe - Koch himself said during his famous 1882 presentation that one-seventh of all human beings die from tuberculosis.

However, since that time, TB has been both curable and preventable, although it continues to afflict and kill millions of people around the world.

Mortality rate falling

According to a March 19 report published by the Robert Koch Institute, the German federal institution responsible for disease control and prevention, there are currently nine million reported cases around the globe, with two million dying annually of the disease; a figure that has been diminishing over time.

The World Health Organization also reports that the TB death rate “dropped 40 percent between 1990 and 2010.”

A woman suffering from tuberculosis covers her face at a clinic in the township of Khayelitsha, on the outskirts of Cape Town, South Africa, Thursday, March 24, 2011. Over 2 million people will contract a form of tuberculosis by 2015 that is difficult to treat, the World Health Organization said Wednesday. (Foto:Schalk van Zuydam/AP/dapd)

Nine million people worldwide are affected by TB

The highly contagious infection frequently affects people suffering from malnutrition or poor hygienic conditions. The same is true for people with weakened immune systems - such as in HIV-infected people.

In its early stages, the Mycobacterium tuberculosis infection demonstrates symptoms similar to flu, with coughing and a fever. Fatigue, loss of appetite, swollen glands, fever and prolonged coughing are progressing signs of the disease.

Treatment is dependent on how far and how early the ailment was detected and how quickly it has spread. A cocktail of well-known antibiotics are often prescribed.

Multidrug-resistant bacteria

Many doctors, however, worry that research into fighting TB has become out of date. The commonly-used antibiotics date to the 1940s and 1950s. As a result there has been an increase in multi-drug resistant TB. As is the case with many bacterial infections, evolution has allowed organisms to adapt and resist attempts to destroy them.

"Treatment against MDR TB is very expensive, lasts over two years and costs 5,000 euros ($6,600) per patient in drug costs alone," says Dr. Sebastian Dietrich, a physician with Doctors without Borders, refering to the multi-drug resistant strains.

The fear is that, as multidrug-resistant tuberculosis bacteria spread, the number of infections could rise instead of fall.

Simplified diagnostic method

ARCHIV - Der Tuberkulose-Erreger Mycobacterium tuberculosis, aufgenommen unter dem Elektronenmikroskop (undatierte Aufnahme vom RKI). Die Zahl der weltweit neu an Tuberkulose erkrankten Menschen ist nach Angaben der Weltgesundheitsorganisation (WHO) 2010 erstmals gefallen. Zudem habe die Infektion im vergangenen Jahr so wenig Todesopfer gefordert wie seit einem Jahrzehnt nicht mehr, teilte die WHO am Dienstag (11.10.2011) in Washington mit. Seit 1990 sei die Zahl der Neuerkrankungen um 40 Prozent gesunken. Foto: Robert-Koch-Institut/Gudrun Holland - nur s/w +++(c) dpa - Bildfunk+++

The bacteria which causes TB was first isolated in 1882

While researchers are working to find appropriate treatments for multidrug-resistant forms of tuberculosis, diagnosing the disease could become a little easier. Today, doctors analyze sputum (a mucus coughed up from the lungs) from patients under a microscope - just like Robert Koch did some 130 years ago when he discovered the tuberculosis bacterium.

In 2010, the World Health Organization endorsed a new diagnostic tool that provides results in hours, rather than days, or weeks. Any technician can be trained in its use in a few short hours. The test uses molecular scanning to determine whether or not the sample is TB-positive.

Doctors without Borders says these new machines are in use in their clinics in Kenya, Malawi, Cambodia, Colombia, Abkhazia (Georgia) and other countries.

The ultimate hope, of course, is that fewer people will develop the disease over time, which can really only happen through vaccination. While there is no adult TB vaccine, many small children in the developed world are given a TB vaccine made from bovine cells - a technique that has been available for nearly a century.

Author: Gudrun Heise / Cyrus Farivar
Editor: Gregg Benzow

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