Acid-fast
Not grown in vitro; in the lab, it's often grown in mouse footpads.
14-day doubling time.
Human pathogen; also been found in armadillos and some other non-human primates.
Route of transmission is not entirely established.
Long-term contact is necessary; it is thought that respiratory, and possibly skin secretions, transmit the bacteria.
Prefers cooler temperatures:
— Tends to infect superficial structures such as the skin and peripheral nerves.
— In some individuals, the anterior eye chambers and nasal cavities are also affected.
Long incubation period: typically between 3-10 years.
Intracellular pathogen:
— Macrophages and the Schwann cells of peripheral nerves.
— In the histology image, we see foamy macrophages infected with
Mycobacterium leprae
— Schwann cell invasion causes demyelination and reduced conduction.
— In the histology image, we see an example of a cutaneous nerve invaded by Mycobacterium leprae.
Leprosy in cutaneous nerve (CDC/Arthur E. Kaye).
Foamy macrophage w/Mycobacterium leprae (Wikipedia; Author Dr. Roshan Nasimudeen).
