A selection of talks on Infectious Diseases
Welcome, this talk will provide a general overview of childhood Tuberculosis.
Robert Koch discovered Mycobacterium tuberculosis in 1882 and proved, through his now famous Koch's postulates, that this organism was indeed the cause of tuberculosis. The DOTS strategy that was developed to control the global TB epidemic relied heavily on sputum smear microscopy. To be able to see the organisms under the microscope, like Koch did, requires at least 10,000 organisms per/ml of sputum. Unfortunately, this excluded most children from care. Young children are unable to expectorate. While most children have pauci-bacillary disease and never reach these high organism loads.
Although Koch demonstrated that Mycobacterium tuberculosis is a necessary cause of disease, we know that it is not sufficient. Globally, up to a third of the world's population is infected. But very few of these people ever develop clinical tuberculosis. There are multiple factors that influence individual vulnerability, as demonstrated in this web of causation. At a global level, poverty and HIV, are probably the two factors that are most important.
This picture demonstrates the gross pathology of pulmonary tuberculosis in the adult lung. You can see multiple areas of caseating necrosis depicted in cavity of the lung apex. This cavity provides the perfect environment for M.tuberculosis to grow and multiply. You can see how the cavity communicates directly with the airway, allowing an escape route for the organism. Tuberculosis is spread by aerosol transmission.