G-

aerobic coccobacillus

intracellular pathogen

Causes "Undulant Fever"

G-

aerobic coccobacillus

intracellular pathogen

Causes Tularemia, "Rabbit Fever"

Capsule inhibits phagocytosis

G+

bacillus

facultative anaerobe

endospore-forming

Endospores taken up by macrophages and releases two exotoxins (edema and lethal toxin)

1. Cutaneous: least serious due to blackish area that prevents systemic infection - 20 % fatality IU
2. GI: 50 % fatality IU
3. Inhalation/Pulmonary (Woolsorter's disease): Most serious - 100% fatality IU

G-

bacillus

facultative anaerobe

Causes the Plague, "Black Death"

Vector: Fleas

Rodent reservoirs

1.  Bubonic

flea bite --> blood and lymph --> proliferate in phagocytic cells --> fever, enlarged lymph nodes (buboes)

50-70% mortality IU

2.  Septicemic

inhalation --> high numbers in blood (septic shock)

3.  Pneumonic

Yersinia in lungs; airborne droplets

100% mortality IU

Aerobic spirochete

Causes leptospirosis

• Infects animals (dogs, cats, rats, horses) --> sheds bacterium in urine for extended periods --> human contact with urine contaminated water --> pathogens enter abrasions or ingested
• Usually not fatal, kidney failure is most common cause of death

Causes:

chills, fever, headaches, aches

G-

obligate aerobe

bacillus

intracellular pathogen

Causes Psittacosis, "Ornithosis"

Bird reservoir

Transmitted through air

20% fatality IU

Signs:

Subclinical to fever, headache, chills, delirium, atypical pneumonia

1.  Metabolically inactive:

infectious (elementary bodies)

2.  Metabolically active:

non-infectious (reticulate bodies)

• Ulcer at site of infection --> lymph node swelling --> can be systemic via lymphatic system
• Most cases due to rabbit contact
• If animal infected dust inhaled, can lead to pneumonia
• Small infective dose needed: 100% IU