
TB occurs more commonly when people live in conditions which promotes its spread. People living in poverty (which is associated with overcrowding), substance abuse, stress unemployment and malnutrition are more likely to get TB.
In an overcrowded, poorly ventilated home TB germs will spread more easily to other members of the household.
A patient suffering from HIV will "catch" TB more easily. In some clinics, more than half the TB patients also have HIV. Young children, especially babies, develop TB more easily and may get serious complications, e.g. TB meningitis. Preventative treatment is given where there is a possibility that a child under the age of five may be exposed to TB.