In cases of pulmonary tuberculosis, it is possible to isolate these bacteria in the sputum in 86% of patients. Every third person in the world is said to have suffered a tuberculosis infection which in roughly 10% can arise again.
Three million people die of tuberculosis every year. The rate of persons with and without infected disease TB is on average higher among the poor than the well-off. In some states of African and Asia, 50% of the inhabitants are said to have indications to be afflicted with outbreaks of TB or have just recently gotten over the illness.
In the states of Europe and North America, the rate is roughly 5%. There, 90% of tuberculosis is reactivations of dormant infections.
In the continent of Africa, there was an almost total absence of tuberculosis, despite lively trade relations with dealers from states where there was rampant tuberculosis, and this right up until colonial times.
In conjunction with the conquest of these states by Great Britain, France, Germany, and Belgium, particularly virulent forms of tuberculosis were introduced in Tanganyika, South Africa, Egypt, Sudan, Zanzibar, the French colonies, and the Congo.
Congo/Zaire was tuberculosis-free still at the beginning of the 20th century but was plagued with tuberculosis in 1921. In 1953, in the United States of America, black people were infected 2.9 times more frequently with tuberculosis than white people.
In 1985, non-whites in the USA were infected 5.2 times more frequently than white people, in relation to their proportion of the population. In 1985, aged between 25 and 44 years, the ratio was 9.1 times more frequent and black people died 16.2 times more frequently from tuberculosis than white people.
The geographical distribution of tuberculosis cases among blacks is largely focal and represents unnecessary disease and death.