subject: Epidemiology of tuberculosis [print this page] EpidemiologyIn EpidemiologyIn
19th-century England one person in five died of Mycobacterium tuberculosis infection. The dramaticdecline in notifications and deaths reflects one of the greatmedical advances of that century. However, tuberculosis remains a common cause of death in the developing world. Eight million new clinical cases occur each year, leading to2 million deaths. One-third of the world's population isinfected with the bacterium that causes tuberculosis.
TBcan infect anyone, but there are well-recognized 'at-risk'population groups in the UK, and these include the elderly,migrants and refugees from countries with a high incidenceof the disease, as occurs in Africa and the Indian subcontinent,those in poor social circumstances, alcoholics,immunosuppressed patients andhospital employees. Tuberculosis is a common complication of HIV infection, and as a consequence the incidencehas increased substantially in some areas of the world.
Mycobacterium bovis was once a common cause ofhuman infection but has now been almost eradicated indeveloped countries by pasteurization of milk and skintesting of cattle, with tuberculin-positive animals beings laughtered.
Mycobacterium bovis was once a common cause of human infection but has now been almost eradicated indeveloped countries by pasteurization of milk and skintesting of cattle, with tuberculin-positive animals beingslaughtered.Mycobacteria other than M. tuberculosis or M. bovismay cause infection in humans, for example M. kansasii,M. xenopi, M. avium and M. intracellulare. The source ofinfection, unlike the droplet route of M. tuberculosis, isgenerally thought to be exposure of susceptible individualsto organisms in water, soil, dust and animals (particularly pigs, chickens, birds and monkeys). The organisms are not transmitted between humans.
