Understanding and combating tuberculosis

Published on March 30, 2021   53 min

A selection of talks on Microbiology

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Hello, my name is David Russell. I'm a professor in the department of microbiology and immunology in the College of Veterinary Medicine at Cornell University. I'm going to talk about tuberculosis today. I've worked on TB for about 30 years. In today's talk, what I want to emphasize is our more recent work on understanding the biology of Mycobacterium tuberculosis within the context of its host, looking at the in vivo biology of the interplay between the pathogen and the host.
I'm sorry about this slide (it's a bit of a boring list), but it will give you the background information that you need to appreciate the significance of this infectious agent. TB is the single greatest cause of death by infectious disease, and there are approximately 1.2 million deaths per year. It's estimated that about a quarter of the human population is infected with this pathogen, and there's a lifetime risk of developing disease that's between 5 and 10 percent over the course of your lifetime. It's the single greatest cause of death in those individuals living with HIV. We have no effective vaccine against tuberculosis. Many people around the world are inoculated with BCG, which is an attenuated form of a related species of Mycobacterium, and this protects against the more severe forms of pediatric tuberculosis but it doesn't protect adults against infection. Effective chemotherapy is very long term, you require 8 to 9 months of treatment with a combination of at least three effective drugs, and there are many side-effects. Not surprisingly there's considerable non-compliance, and this leads to constant emergence of heritable drug resistance. We lack any biomarkers that are either predictive of disease progression or indicative of cure status, so we don't know if the drug treatment is actually working effectively to control or eradicate the disease.