An Indian tuberculosis patient sits with his brother at the Rajan Babu Tuberculosis Hospital in New Delhi Getty

World Tuberculosis Day is marked every year on 24 March, highlighting one of the world's top health challenges. With nine million new cases and 1.5 million deaths each year, tuberculosis is an ongoing epidemic.

For World TB Day 2015, the United Nations, the Stop TB Partnership and the World Health Organization are calling on all governments and health organisations to mobilise political and social commitment for further progress towards eliminating the disease as a public health burden. The theme this year is "Reach the 3 Million: Reach, Treat, Cure Everyone" – aimed at securing care for the three million who fail to be treated every year.

The date commemorates the day in 1882 when Dr Robert Koch, the German physician and pioneering microbiologist, announced to the University of Berlin's Institute of Hygiene that he had discovered the cause of tuberculosis. His discovery marked a turning point in the story of the virulent human infectious disease.

tuberculosis in Russia
An information board is on display on the fence of a tuberculosis hospital in Russia's Siberian city of Krasnoyarsk Reuters

Modern problem

Yet over a century on, the disease continues to be a public health problem, with the highest rates in Sub-Saharan Africa. A report by the European Centre for Disease Prevention and Control and WHO found that 1,000 people a day throughout Europe develop the disease and although the continent has experienced an annual 6% decline, Europe will not be TB-free until the next century.

There has been a sustained decline in cases over the last decade but rates of multi-drug resistant tuberculosis, MDR-TB, remain at very high levels.

WHO regional director for Europe, Zsuzsanna Jakab, said only 50% of an estimated 75,000 multi-drug resistant TB patients were found in 2013 and just half were successfully cured.

"Multi-drug resistant TB is still ravaging the European region, making it the most affected area of the entire world," he said.