MBI 121 Animal athogens

Soilborne
• Clostridium tetani
– 2nd most potent toxin known
• Anaerobic, Gram pos. rod
• Spores enter wound
• Treat with sedatives, antibiotics, antitoxin
• TDaP vaccine
– need tetanus booster every 10 years

• First pandemic : Africa, 542 BCE
• 60 years - millions died
• collapse of Roman Empire
• Second : Europe, 1300’s
• killed 1/3 of population
• “Black Death”
• Late 1800’s - early 1900’s: 10 million deaths in India alone
• Rodent disease
• flea bites infected rat & then bites human
• Public health changes
Enlarged lymphnodes (bubous)

Rickettsia species
Gram negative
– obligate intracellular bacterium
• Family of diseases
– Transmitted by ticks or lice (dep. on species)
• Typhus fever: “slate-wiper”
– R. prowazekii; head & body lice
– decimated Aztecs
– Russian defeat of Napoleon
– caused 3 million deaths in WW I & WW II

Called the “Great Pox”
First recorded European epidemic in 1400’s
Caused by Treponema pallidum
Number of cases increasing in North America

First symptom is “chancre”
Painless, circular, hard sore
Usually on genitals
Persists for 2-6 weeks, then disappears

Penicillin effective treatment in
primary & secondary stages

“Gummae” - lesions on blood vessels
burst in brain ® paralysis, insanity

Sharecroppers (600)
Study treatment of syphilis
Not informed of diagnosis
“bad blood”
– free treatment
– free ride to clinic
– one hot meal/day
– $50 for funeral
– Penicillin withheld
– 1972 - study halted
– One of greatest ethical breaches in US medicine
– New regulations
– 1973 - NAACP class action suit
– $9 million
– US gov’t free medical & burial service to living; health services to wives, widows, children infected

• 2nd most common reported microbial disease (aka “the clap”)
– 700K cases/yr in US
• N. gonorrhoeae: Gram neg diplococcus
• Symptoms: abdominal pain, burning sensation, discharge from urethra
• Infants get Gonorrhea as they pass thru birth canal
– grow in eyes & mouth
– blindness
• Most states require newborns to get silver nitrate or antibiotics in eyes
• Antibiotic resistant strains

• Most common reported microbial disease
– 2.8 million cases/yr
• Chlamydia trachomatis
– obligate intracellular bacterium
• Symptoms very similar to gonorrhea
– Can by “asymptomatic”
• Can cause infertility if untreated

Antiviral medications - side effects; high mutations
Prevention key
Stop/slow transmission

i. Teach immune system how to fight

English physician; 1798 landmark work
Milkmaids got cowpox, never smallpox
i. 3D shapes are similar
Napoleon ordered army inoculated
Thomas Jefferson pushed effort to vaccinate Americans

Attenuated
Inactivated
Recombinant

virus can still deuplicate, but at a much slower rate

No viral DNA is associated with virus

1 or more proteins injected into host