EPIDEMIOLOGY OF TUBERCULOSIS IN EUROPE

The risk of exposure to tuberculosis depends upon the incidence of inf ectious cases, the duration of their infectiousness, and the number of personal interactions an infectious case accomplishes per unit of tim e. The risk of infection, given exposure, depends on the density of in fectious particles in the ambient air x duration of exposure to that a ir, The risk of infection has rapidly declined in Europe for decades b y 10% or more annually, resulting in a shift of the infected to the ol dest generation, Thus, with the passage of time, cohorts are increasin gly replaced by successive cohorts with less and less infection. The r isk of progression from infection to tuberculosis depends largely on t he cellular immune system's capability to prevent tubercle bacilli fro m multiplication. The three most important risk factors for the progre ssion from subclinical infection to tuberculosis include: human immuno deficiency virus (HIV) infection, recency of infection, and fibrotic r esiduals from earlier tuberculosis, The number of tuberculosis cases h as rapidly decreased during this century, accompanied by an upward shi ft in the median age of patients, In recent years, tuberculosis among immigrants has gained in significance and is likely to continue to do so, while HIV infection has limited impact on the tuberculosis epidemi c in Europe. The risk of dying from tuberculosis is determined by form and site of disease, and patient's and doctor's delay, The number of deaths caused by tuberculosis in Europe is rapidly decreasing.