Nevertheless, scale-up of sputum smear microscopy has not succeeded in achieving dramatic declines in tuberculosis incidence.
Possible reasons for the lack of impact include the poor sensitivity of smear microscopy, particularly among HIV-infected persons and children, and the occurrence of many cases of transmission before people receive a tuberculosis diagnosis and treatment.
The infectiousness and duration thereof for a person with tuberculosis depend on host and bacterial factors.
Persons with smear-positive pulmonary tuberculosis are highly infectious, and the degree of infectiousness is thought to increase with the degree of smear positivity.
The lessons learned from studying tuberculosis transmission are also relevant to reducing transmission of other airborne pathogens. William Osler, in 1909, wrote that “all who mix with tuberculosis patients got infected, but remained well so long as they took care of themselves and kept the soil in a condition unfavorable for the growth of the seed” .
Over the intervening century of tuberculosis research, our understanding of tuberculosis transmission and disease progression has improved: in 1920, Devoto recognized that healthcare workers were at risk of developing tuberculosis; in 1934, Wells described the falling and evaporation times for droplet nuclei ; and Riley, in 1961, described the deposition of airborne bacteria in the lung  and, in 1960–1962, described aerial dissemination of in a tuberculosis ward [11, 12].f-Create a plan for follow-up and referral if needed.What Awaits you: On-time delivery guarantee Masters and Ph D-level writers Automatic plagiarism check 100% Privacy and Confidentiality High Quality custom-written papers Use the order calculator below and get started!Individuals with index tuberculosis cases who are HIV infected, particularly those with advanced immunosuppression, were hypothesized to be less likely than HIV-uninfected individuals with tuberculosis to transmit to household contacts, possibly because of a greater likelihood of having smear-negative tuberculosis and a shorter duration of infectiousness due to more rapid progression to death [18, 19].Antiretroviral therapy reduces the risk of tuberculosis among people with HIV infection (PLHIV) by 67% and, if scaled up, may contribute to a reduction in tuberculosis case rates at a population level [20, 21].Persons with active pulmonary or laryngeal tuberculosis generate droplet nuclei that contain through coughing, singing, shouting, sneezing, or any other forceful expiratory maneuver that shears respiratory secretions from the airways, with coughing being the most efficient at generating infectious aerosols .Appropriate treatment of individuals with infectious tuberculosis results in a rapid reduction in infectiousness .Tuberculosis case notifications among children infections to zero.The purpose of this article is to give a high-level overview of the discussion at the workshop regarding what is known about tuberculosis transmission and to set the scene for the articles that address specific aspects of tuberculosis transmission.In 2015, there were an estimated 1.8 million deaths due to tuberculosis, including HIV-associated tuberculosis deaths, making tuberculosis the leading cause of death from an infectious disease .Latent infection has recently been reestimated at 24% .