The document describes three pathogens: Mycobacterium leprae, Bacillus anthracis, and Herpes simplex virus 1. M. leprae causes Hansen's disease (leprosy) and targets areas of lower body temperature like skin and nerves, manifesting as mild or severe skin lesions. B. anthracis infects livestock through spores in soil and humans through contact with infected animals, causing mild to severe and sometimes fatal skin, gastrointestinal, or pulmonary anthrax. Herpes simplex virus 1 causes cold sores via the trigeminal nerve and establishes latency in nerves, periodically reactivating and traveling back to the skin, usually during stress.

1. Mycobacterium
leprae
• Gram +, rod
• Animals with lower temperature are
the natural reservoir ‐ armadillos
• Pathogen (latent, symptoms absent un<l a=er 1 year) targets skin,
peripheral nerves and mucous membranes (areas with lower body
temperature), transmission is not well‐understood
• Causes Hansen’s disease (renaming of leprosy due to s<gma)
• Tuberculoid – mild, few skin lesions, less common disease
• Lepromatus – severe, more than 6 skin lesions, skin numbness &
weak muscles, claw‐shaped thumbs (neuropathy), renal failure,
glaucoma
• Numbness leads to repeated, undetected injuries and loss of
digits or tes<cles
• Treated with rifampin, dapsone (life<me an<bio<c treatment)
• 250,000 cases world‐wide annually (100 in the U.S.)

2. Bacillus anthracis
• Gram +, rod
• Pathogen infects livestock that inhale spores, soil
harbors spores that become airborne. Humans usually
become infected by contact with infected animals
(contact with an open wound or consump<on of
contaminated meat), and very rarely by inhaling spores
• 3 forms of anthrax
• Mild skin lesions, swollen lymph nodes
• GI anthrax – nausea, fever, bloody diarrhea and vomi<ng,
swollen lymph nodes
• Pulmonary anthrax – flu‐like symptoms, high fever,
meningi<s, usually fatal

3. Herpes Simplex I virus
• Member of Herpesviridae – double‐stranded DNA, polyhedral
protein capsid, lipid envelope
• Causes cold sores (oral herpes), but only because the virus
“prefers” the trigeminal nerve – can infect any part of the body
(skin)
– Transferred by contact with an infected person, virus present
even when lesions are absent
• Latent and recurrent virus – causes lesions
– Symptoms may not show up for weeks or years
– Virus migrates to the nerves and travels back to the skin,
usually associated with stress
• OTC – lysine (amino acid) supplementa<on, Abreva
• An<viral treatment – Famvir, Valtrex