Tuberculosis - INTRODUCTION

TRANSMISSION AND INFECTION

Primary and Secondary TB

DIAGNOSIS OF INFECTION AND DISEASE

TREATMENT AND PREVENTION

HISTORY

CURRENT PREVALENCE OF TB



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CURRENT PREVALENCE OF TB Tuberculosis




Global Spread of TB | Tuberculosis Public Health Systems

As the incidence of TB continued to decline in the early 1980s, most medical experts expected that the disease would be completely eliminated in industrialized nations by the year 2010. But by the mid-1980s, the number of TB cases began to increase—between 1985 and 1991, the number of reported cases in the United States increased 20 percent. Worldwide the incidence also skyrocketed in this period, and by the year 2000, the TB bacteria had infected more than one-third of the world’s population. (CURRENT PREVALENCE OF TB - Tuberculosis, Global Spread of TB, Tuberculosis Public Health Systems)

Multiple factors contribute to the global increase in TB. Infection with the human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS), is the single greatest risk for progression of TB infection to disease. People with HIV have weakened immune systems that increase their susceptibility to TB, and in these people, TB often progresses rapidly from the primary to the secondary stage. The increase of TB incidence is highest in Africa and Asia, areas with the highest number of people infected with HIV. (CURRENT PREVALENCE OF TB - Tuberculosis, Global Spread of TB, Tuberculosis Public Health Systems)

A second factor contributing to TB resurgence is the failure of patients to complete the full six to nine months of antibiotic therapy required to cure the disease. Many people stop taking antibiotics when they begin to feel healthier, but successful treatment of TB requires therapy beyond the period of obvious symptoms. When patients fail to follow the prescribed treatment, they may become actively infectious, spreading the disease to others. An infected person may infect as many as 10 to 15 other people in a single year. Failure to complete the full round of treatment also can cause the emergence of TB bacterial strains with acquired drug resistance, further complicating treatment by increasing the length and cost of therapy. (CURRENT PREVALENCE OF TB - Tuberculosis, Global Spread of TB, Tuberculosis Public Health Systems)

The emergence of strains of bacteria that are resistant to multiple drug therapy is a serious problem, particularly because no ready drug treatment is available to combat newly emerging strains. To improve compliance, the WHO strongly recommends that all countries, especially those in Africa and Asia, adopt a program called directly observed treatment, short-course (DOTS). DOTS requires health workers to monitor patients to make sure that they follow the complete course of treatment. The success rate and the cost effectiveness of this program have been proven around the world. Epidemics in New York City, Tanzania, Peru, and China in the early 1990s were brought under control using DOTS. (CURRENT PREVALENCE OF TB - Tuberculosis, Global Spread of TB, Tuberculosis Public Health Systems)

Migration, international air travel, and tourism also have contributed to the global spread of TB. The extreme difficulty of screening immigrants and travelers for TB allows the disease to cross international borders easily. The substantial increase in homelessness, and the related circumstances of poverty, crowding, and malnutrition, also contributed to the increased incidence of TB in the United States and other industrialized countries during the early 1990s. (CURRENT PREVALENCE OF TB - Tuberculosis, Global Spread of TB, Tuberculosis Public Health Systems)

While industrialized nations with good public health systems have been able to control the recent TB resurgence, curbing the spread of TB on a global scale will require ongoing international efforts. In the future, combating TB throughout the world will require advances in molecular biology, research into the genetics of TB in order to understand drug resistance, and the continuous development of new drugs, as well as the prospect of synthesizing additional vaccines. (CURRENT PREVALENCE OF TB - Tuberculosis, Global Spread of TB, Tuberculosis Public Health Systems)

CURRENT PREVALENCE OF TB (Tuberculosis) | Global Spread of TB | Tuberculosis Public Health Systems