A new study has shown that probably one in four people in the world carry the tuberculosis bacterium in the body. 

The study was published in the 'European Respiratory Journal.' It has previously been estimated that somewhere between one-third and one-fourth have latent tuberculosis, but the new study, which is based on tests from 351,811 individuals, indicated that it is between one-fifth and one-fourth, depending on the test method used. The disease tuberculosis is caused by the bacterium Mycobacterium Tuberculosis, which affects more than 10 million people every year, and kills up to 2 million, making it the most deadly of infectious diseases. 

In addition, many are infected with the tuberculosis bacterium without having active disease, which is called latent tuberculosis. 
The researchers have reviewed 88 scientific studies from 36 different countries, and on the basis of this epidemiological evidence they have estimated a prevalence also in those countries where no studies are available, additionally, they have calculated the approximate total global prevalence. The study emphasized that it will be extremely difficult to reach the goal of eliminating tuberculosis by 2035, which is the aim of the World Health Organization. 

At any rate, the objective cannot be achieved without treating the large incidence of latent tuberculosis, since all infected people are at risk of developing active tuberculosis disease later in life, said Christian Wejse, an infectious disease specialist at Aarhus University Hospital.