A histopathological study of pulmonary infection of mice with Mycobacterium lepraemurium

Intranasal instillation of Mycobacterium lepraemurium (MLM) into mice produced pulmonary infection. MLM multiplied rapidly in the lung tissue during the first few weeks without involvement of other organs. The increase in number, size and confluence of lung granulomas paralleled the multiplication of MLM which could be found both intracellularly and extracellularly. It is postulated that extracellular bacteria may find their way to the bloodstream and thus spread to other visceral organs. Extensive destruction of alveoli and occupation of airspaces by lepra-like cells invariably occurred as the disease progressed.