Tuberculosis in a low prevalence country: A wolf in sheep's clothing.

In low prevalence countries group epidemics or "micro-epidemics" of tuberculosis behave as a point-prevalence epidemic. Contact tracing follows the "Stone-in-the-Pond Principle", persons belonging to the inner circle of a source of infection being examined first. Important factors contributing to the occurrence of a micro-epidemic are prolonged patient's and doctor's delay and the dark damp atmospheres of discotheques.