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Hello, my name is David Dowdy.
I'm an associate professor in the Department of Epidemiology at the Johns Hopkins
Bloomberg School of Public Health.
It's my pleasure today to give you an introduction to the epidemiology of tuberculosis (or TB).
TB is the leading single-agent cause of infectious deaths worldwide,
or at least was before the COVID-19 pandemic.
Over time, it is estimated that TB has killed over one billion people since 1800.
Every year, TB continues to cause an estimated 1.4 million deaths every year,
despite being fully curable in at least 95 per cent of all cases.
The epidemiology of TB reflects a series of unique characteristics, that include those of the pathogen,
those of the host, and those of the environment.
From a pathogen perspective, TB is one of very few diseases that are truly airborne,
so everyone is at risk, because everyone has to breathe.
From a host perspective, most people who are infected with TB are able to contain this infection
without developing disease, but a number of people do develop disease,
and this so-called 'reactivation' can occur many years after the initial infection.
From an environmental perspective, there are a number of environmental factors that raise
the risk of TB progression and of TB infection, including poverty,
but also things such as crowding and malnutrition.
All three of these components - the pathogen, host, and environment -
contribute to the epidemiology of tuberculosis worldwide.