Tuberculosis (20th Century-Present)

Global Threat

Worldwide, approximately 9 million people were diagnosed with TB each year in the 21st century, with more than half the cases occurring in Asia and approximately one-third in Africa. More than one million people continue to die of TB annually, with an estimated half-million more succumbing to TB in the context of human immunodeficiency virus (HIV) infection. The ongoing HIV epidemic presents a significant barrier to TB control: resultant immunodeficiency predisposes to developing active TB infection, but many TB patients continue to be untested and untreated for HIV, most often due to lack of resources. Although the current burden of disease is carried primarily by developing nations in Asia and Africa, prior to 1900s, illness and death from TB (often referred to as consumption) was widespread in Europe and North America. Evidence of TB epidemics in multiple regions of the globe hundreds and thousands of years ago has been documented. Although rates of infection briefly declined at the turn of 20th century (likely due improved living conditions), the devastation of World War I contributed to a resurgence in cases. Fortunately, several scientific advances occurred early in the 1900s, and permitted greater public health measures to control and treat TB.

Discovery of the pathogen causing TB played a key role in subsequent disease detection, prevention, and treatment. Robert Koch, a German physician and scientist, was able to identify the infectious organism that caused the disease at the end of the 19th century, receiving the Nobel Prize in 1905 for his discovery. He also created tuberculin—a fragment of the pathogen that produced a strong immune response when injected into an animal or human already infected with TB. Attempts to use tuberculin as treatment and preventative vaccination for TB failed, but the substance became useful in screening cattle for the disease.

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