China
Africa
Explore chapters and articles related to this topic
Antibiotics: The Battle with the Microbes
Published in Richard J. Sundberg, The Chemical Century, 2017
One of the bacterial infections against which penicillin is ineffective is tuberculosis (TB). TB has been present in man throughout recorded history. It is estimated that the disease caused a billion deaths in the nineteenth and 20th centuries. It is a contagious infection that can be transmitted by contaminated materials such as aerosols from a cough or sneeze. The bacterium can survive for some time in dust. Tuberculosis can also be acquired from contaminated food, in particular milk from tubercular cows. Not everyone exposed to the bacterium develops tuberculosis. The estimated rate of infection is 10%. In some individuals exposure results in control of the bacteria by encapsulation into tubercles. Such individuals give a positive skin test for exposure, but do not develop the disease unless the latent bacteria are activated. Tuberculosis was a major disease in the United States and the world through the first half of the 20th century. The most common infections were in the lung and in the early 20th century as much as a third of the population had been exposed. The only treatment was isolation and rest. There were sanatoriums for tuberculosis patients throughout the country. The mortality rate in the United States is thought to have been about 50%. The patients who survived often harbored residual pockets of dormant bacteria that could be reactivated, resulting in a relapse years after the initial infection. Currently, there are an estimated 8 million new cases and about 2 million deaths annually, most in the developing world.
Dynamics of cough and particulate behaviour in the human airway
Published in Mathematical and Computer Modelling of Dynamical Systems, 2021
Olusegun J. Ilegbusi, Don Nadun S Kuruppumullage, Bari Hoffman
Cough is an airway protective mechanism resulting from a coordinated series of respiratory, laryngeal, and pharyngeal muscle activity and serves both preventative and corrective roles in pulmonary health [1]. It is a response to the presence of unwanted penetrants such as virus-laden droplets and particulates in the lower airways. This function is performed through the generation of high-velocity explosive cough airflow that clears the aspirate and mucus from the airway. The objective of this study is to apply computational fluid dynamics model to characterize the flow and penetrant behaviour under cough in the human airway, and assess the clearance capacity of cough relative to prescribed penetrant properties